diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..f7c1500 --- /dev/null +++ b/.gitignore @@ -0,0 +1,12 @@ +*.a +*.so.* +*.1 +*.o +*.bak +*.exe +examples/read +examples/write +examples/write2 +examples/version +examples/unicode +html diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..94a9ed0 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Makefile b/Makefile new file mode 100755 index 0000000..07aa4b0 --- /dev/null +++ b/Makefile @@ -0,0 +1,65 @@ +# tinyclipboard - a cross-platform C library for accessing the clipboard. +# +# Copyright © 2016 Marvin Gülker +# +# All rights reserved. See the README and LICENSE files for the +# licensing conditions. + +CC := cc +AR := ar +INSTALL := install +CFLAGS := -Wall -Wextra -pedantic -Wno-unused-parameter -g +LDFLAGS := -g +DESTDIR := +PREFIX := /usr/local + +sonum := 1 +sominnum := 0 +soname := libtinyclipboard.so.$(sonum) +realname := $(soname).$(sominnum) + +all: compile + +tinyclipboard.o: src/tinyclipboard.c include/tinyclipboard.h + $(CC) $(CFLAGS) $< -c -o $@ +tinyclipboard.fpic.o: src/tinyclipboard.c include/tinyclipboard.h + $(CC) $(CFLAGS) -fPIC $< -c -o $@ +libtinyclipboard.a: tinyclipboard.o + $(AR) rcs $@ $< +$(realname): tinyclipboard.fpic.o + $(CC) $(LDFLAGS) -shared -Wl,-soname,$(soname) -o $@ $< + +compile: libtinyclipboard.a $(realname) + +examples_x11: compile + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include read.c ../libtinyclipboard.a -lX11 -o read + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include write.c ../libtinyclipboard.a -lX11 -o write + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include write2.c ../libtinyclipboard.a -lX11 -o write2 + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include version.c ../libtinyclipboard.a -lX11 -o version + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include unicode.c ../libtinyclipboard.a -lX11 -o unicode + +examples_win32: compile + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include read.c ../libtinyclipboard.a -o read + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include write.c ../libtinyclipboard.a -o write + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include write2.c ../libtinyclipboard.a -o write2 + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include version.c ../libtinyclipboard.a -o version + cd examples && $(CC) $(CFLAGS) $(LDLFLAGS) -I../include unicode.c ../libtinyclipboard.a -o unicode + +install: compile + $(INSTALL) -m 0644 -D include/tinyclipboard.h $(DESTDIR)$(PREFIX)/include/tinyclipboard.h + $(INSTALL) -m 0644 -D libtinyclipboard.so.1.0 $(DESTDIR)$(PREFIX)/lib/libtinyclipboard.so.1.0 + $(INSTALL) -m 0644 -D libtinyclipboard.a $(DESTDIR)$(PREFIX)/lib/libtinyclipboard.a + for manpage in `ls man/*.3` ; do \ + $(INSTALL) -m 0644 -D $$manpage $(DESTDIR)$(PREFIX)/share/man/man3/`basename $$manpage` ; \ + done + +clean: + rm -f *.o *.a *.so.* + rm -f examples/{read,write,write2,version} + rm -rf html + +htmlman: + mkdir -p html + for manpage in `ls man/*.3` ; do \ + groff -k -T html -m mandoc $$manpage > html/`basename $$manpage | sed s/\\\./_/`.html ; \ + done diff --git a/README.md b/README.md new file mode 100644 index 0000000..3d4c6f5 --- /dev/null +++ b/README.md @@ -0,0 +1,170 @@ +tinyclipboard +============= + +tinyclipboard is a cross-platform C library for accessing the +operating system’s clipboard. It is intended to be as standalone as +possible and not depend on any external libraries except those +absolutely required for clipboard access (e.g. libX11 for X +servers). Especially it is independant from any large GUI toolkit +libraries. + +tinyclipboard gives access to read and write text strings from and to +the clipboard. Images and other nontextual data formats are not +supported. + +The library puts a strong focus on UTF-8 text. Any string you retrieve +from the clipboard will be returned to you in UTF-8, and any string +you pass is expected to be encoded in UTF-8. Under the hood, +tinyclipboard takes care of converting the UTF-8 string into the +encoding used by the underlying clipboard system. + +Supported systems +----------------- + +These operating systems and graphics stacks are supported currently: + +* Linux systems using X11 +* Windows + +Building +-------- + +You can build and use the tinyclipboard library in one of three ways: + +1. Compile and use it as a static library as part of your project + (recommended) +2. Compile and use it directly in your project +3. Compile and use it as a dynamic library + +The tinyclipboard library consists of one header file and one C +sourcecode file. It is recommended to build tinyclipboard as part of +your project and link it into your executable as a static library +(option 1 above). Since it is such a small library, you might also +consider to simply drop the two files directly into your project +without a separate library step (option 2, see below for more +information). Finally, tinyclipboard’s Makefile also builds a dynamic +library (option 3). + +To build the static and dynamic library files, issue + +~~~~~~~~~~~~~~~~~~~~ +$ make +~~~~~~~~~~~~~~~~~~~~ + +in the project directory. You will be left with both a `.a` file +(static library) and a `.so` file (dynamic library) in the project +root directory. + +If you wish to install the tinyclipboard library to your system +instead of building it as part of your project, you can issue the +usual + +~~~~~~~~~~~~~~~~~~~~ +$ make install +~~~~~~~~~~~~~~~~~~~~ + +command. The `install` task understands the usual `PREFIX` and +`DESTDIR` variables in case you need them. + +If you want to build the tinyclipboard library as part of your +project, simply drop the header and C source code file into your +source tree and have your preferred build system compile and link them +in. The only thing to consider here is that you need to link in libX11 +(`-lX11`) when you build your program for an X11 system. If you are +building an application with a graphical user interface, chances are +high that you need to link in libX11 anyawy. + +Examples +-------- + +There are some examples of use provided in the `examples/` directory +in the source tree. To build them, issue one of: + +~~~~~~~~~~~~~~~~~~~~ +$ make examples_x11 # X11 systems +$ make examples_win32 # Windows systems +~~~~~~~~~~~~~~~~~~~~ + +in the toplevel directory. The different commands are to accomodate +the different linking needs (X11 systems need `-lX11` to be linked in). + +Usage +----- + +The tinyclipboard library provides three main functions: + +* `tiny_clipread()`, which returns the content of the clipboard. +* `tiny_clipwrite()`, which replaces the content of the clipboard. +* `tiny_clipnwrite()`, which is the same as `tiny_clipwrite()` with + the exception that it allows to embed NUL bytes into the clipboard + on X11. + +For version information, the `tiny_clipversion()` function is +available. + +Minimal example of how to read from the clipboard: + +~~~~~~~~~~~~~~~~~~~~ c +#include +#include +#include + +int main() +{ + char* str = tiny_clipread(NULL); + if (str) { + printf("The clipboard contains: '%s'\n", str); + free(str); + } + else { + printf("No text in clipboard.\n"); + } + + return 0; +} +~~~~~~~~~~~~~~~~~~~~ + +Writing is a little more difficult especially on X11 systems. Refer to +the tiny_clipwrite(3) and tiny_clipnwrite(3) manpages. + +Documentation +------------- + +Full and detailed documentation of the functions provided by the +tinyclipboard library is available in form of manpages in the `man/` +directory of the source tree. Each function is described in detail, +usually with examples. + +Contact information +------------------- + +The tinyclipboard library was written by Marvin Gülker +. + +If you find any bugs or want to contribute to the tinyclipboard +library, feel free to contact me under this email address. + +Licensing +--------- + +For normal use, I offer the tinyclipboard library under the terms of +the GNU GPLv3+ license. For other licensing options, please contact me +under the email address mentioned above. + +### GPL statement + +tinyclipboard is a cross-platform clipboard library written in C. +Copyright © 2016 Marvin Gülker + +This program is free software: you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation, either version 3 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program. If not, see . diff --git a/examples/read.c b/examples/read.c new file mode 100755 index 0000000..ef54789 --- /dev/null +++ b/examples/read.c @@ -0,0 +1,38 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include +#include "tinyclipboard.h" + +int main() +{ + /* Full example with length query */ + int len = 0; + char* str = tiny_clipread(&len); + + if (str) { + printf("The clipboard contains %d bytes: '%s'\n", len, str); + free(str); + } + else { + printf("No text in clipboard or no clipboard owner.\n"); + } + + /* Query for a NUL-terminated string only */ + str = tiny_clipread(NULL); + if (str) { + printf("The clipboard contains: '%s'\n", str); + free(str); + } + else { + printf("No text in clipboard or no clipboard owner.\n"); + } + + return 0; +} diff --git a/examples/unicode.c b/examples/unicode.c new file mode 100644 index 0000000..6400b02 --- /dev/null +++ b/examples/unicode.c @@ -0,0 +1,32 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include +#include "tinyclipboard.h" + +int main() +{ +#ifdef _WIN32 + /* Fix buffer problem with mintty. */ + setvbuf(stdout, NULL, _IONBF, 0); +#endif + + /* If your editor does not display all these Unicode characters, + * you need to switch to a font that contains them. Similaryly, + * if the application you paste this text into does not display + * the characters, you need to set it to use a different font that + * contains the glyphs in question. */ + tiny_clipwrite("Umlaut ü, Buckel-ß, greek β. This is cool™. More‽ ☺\n"); + + /* Clipboard may vanish on X11 if we exit, so don't. */ + for(;;) + sleep(1); + + return 0; +} diff --git a/examples/version.c b/examples/version.c new file mode 100644 index 0000000..a2a029d --- /dev/null +++ b/examples/version.c @@ -0,0 +1,16 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include "tinyclipboard.h" + +int main() +{ + printf("%s\n", tiny_clipversion()); + return 0; +} diff --git a/examples/write.c b/examples/write.c new file mode 100755 index 0000000..c021cb4 --- /dev/null +++ b/examples/write.c @@ -0,0 +1,27 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include +#include "tinyclipboard.h" + +int main() +{ +#ifdef _WIN32 + /* Fix buffer problem with mintty. */ + setvbuf(stdout, NULL, _IONBF, 0); +#endif + + tiny_clipwrite("This is a test.\n"); + + /* Clipboard may vanish on X11 if we exit, so don't. */ + for(;;) + sleep(1); + + return 0; +} diff --git a/examples/write2.c b/examples/write2.c new file mode 100644 index 0000000..6a105f7 --- /dev/null +++ b/examples/write2.c @@ -0,0 +1,40 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include +#include +#include "tinyclipboard.h" + +int main() +{ +#ifdef _WIN32 + /* Fix buffer problem with mintty. */ + setvbuf(stdout, NULL, _IONBF, 0); +#endif + + printf("Writing 'This is a test' to the clipboard.\n"); + if (tiny_clipwrite("This is a test.") != -1) + printf("Success.\n"); + else + printf("Failure.\n"); + + sleep(10); + + printf("Writing 'another test' to the clipboard.\n"); + if (tiny_clipnwrite("another test", strlen("another test")) != -1) + printf("Success.\n"); + else + printf("Failure.\n"); + + sleep(10); + + printf("Exiting.\n"); + + return 0; +} diff --git a/include/tinyclipboard.h b/include/tinyclipboard.h new file mode 100755 index 0000000..2e7adf5 --- /dev/null +++ b/include/tinyclipboard.h @@ -0,0 +1,19 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#ifndef TINYCLIPBOARD_H +#define TINYCLIPBOARD_H +#define TINYCLIPBOARD_VERSION 20160100L +#define TINYCLIPBOARD_VERSION_POSTFIX "" + +const char* tiny_clipversion(); +char* tiny_clipread(int* len); +int tiny_clipwrite(const char* text); +int tiny_clipnwrite(const char* text, int len); + +#endif diff --git a/man/tiny_clipnwrite.3 b/man/tiny_clipnwrite.3 new file mode 100644 index 0000000..0351331 --- /dev/null +++ b/man/tiny_clipnwrite.3 @@ -0,0 +1,254 @@ +.\" tinyclipboard - a cross-platform C library for accessing the clipboard. +.\" +.\" Copyright © 2016 Marvin Gülker +.\" +.\" All rights reserved. See the README and LICENSE files for the +.\" licensing conditions. +.TH tiny_clipnwrite "3" "January 2016" "Marvin Gülker" "tinyclipboard" +.SH NAME +tiny_clipwrite, tiny_clipnwrite \- Write to the OS clipboard + +.SH SYNOPSIS +.nf +.B #include +.sp +.B int tiny_clipnwrite\fR(\fBconst char*\fR \fItext\fR, \fBint\fR \fIlen\fR); +.B int tiny_clipwrite\fR(\fBconst char*\fR \fItext\fR); + +.SH DESCRIPTION +.PP +The \fBtiny_clipnwrite()\fR function reads \fIlen\fR bytes from the +string buffer pointed to by \fItext\fR and writes them to the +underlying graphics stack’s clipboard. There are no size checks +performed while reading from the buffer, so that this function allows +you to embed \fBNUL\fR bytes into the clipboard. It is your +responsibility to set the \fIlen\fR argument accordingly. \fItext\fR is +expected to be encoded in UTF-8 regardless of the current locale’s +encoding. + +.PP +The \fBtiny_clipwrite()\fR function behaves like the +\fBtiny_clipnwrite()\fR function, except that it determines the length +of the string to write to the clipboard by utilising the \fBstrlen(3)\fR +function on its \fItext\fR argument. It is thus not possible to copy a +string containing \fBNUL\fR bytes into the clipboard using this +function; use \fBtiny_clipnwrite()\fR if you need to do this. + +.SH RETURN VALUE +.PP +The \fBtiny_clipnwrite()\fR and \fBtiny_clipwrite()\fR functions +return 0 if the data was written successfully into the operating +system’s clipboard. Otherwise they return -1 and set \fIerrno\fR to +indicate the error. + +.SH ERRORS +.SS X11 systems +.PP +This function indicates the following errors on systems using an X11 +server for graphics management: + +.TP +.BR ECHILD +Error when trying to create the child process (see \fBNOTES\fR below). +.TP +.BR ECONNREFUSED +Failed to connect to the X server. This most likely means that your +program is not run in a graphical environment (for example, it may be +run from the Linux virtual console). +.TP +.BR EPIPE +Child process pipe creation failure (see \fBNOTES\fR below). + +.SS Win32 systems +.PP +This function indicates the following errors on Windows systems: + +.TP +.BR EAGAIN +Another process has opened the clipboard currently. +.TP +.BR ECANCELED +Unexpected function failure after using a Windows API function as +advertised by a prior return value. Encountering this \fIerrno\fR +value might indicate a bug in \fItinyclipboard\fR. +.TP +.BR EINVAL +The \fItext\fR argument was not valid UTF-8. +.TP +.BR ENOTSUP +Creation of the invisible GUI window (see \fBNOTES\fR below) failed. + +.SH EXAMPLES +.SS Writing a string into the clipboard + +.PP +This example writes a static string into the operating system’s +clipboard. + +.sp +.RS 4 +.nf +\fB +#include +#include +#include + +int main() { + if (tiny_clipwrite("This is an example.") < 0) { + perror("Failed to write clipboard"); + return 1; + } + else { + printf("Wrote clipboard successfully.\\n"); + } + + /* Keep program running so it also works on X11 systems without + * a clipboard manager. */ + getchar(); + + return 0; +} +\fR +.RE + +.SH NOTES +.PP +The clipboard is a highly operating-system specific resource. The +\fItinyclipboard\fR library strives to hide the complexities of +certain system’s clipboard systems (especially X11’s) behind a set of +simple, highlevel functions that allow the programmer to uniformly +access any supported operating system’s clipboard system. This +highlevel interface sacrifices access to some more granular features +each of the respective systems provides, but if you need these, you +should probably not be using a cross-platform clipboard library +anyway. + +.PP +Across all operating systems and graphics stacks, the +\fBtiny_cipnwrite()\fR and \fBtiny_clipwrite()\fR functions do not +require your application to be a GUI application. However, they open +invisible windows to interact with the clipboard if it is +required. From this follows that while you do not have to create your +application as a GUI application, you have to link in your system’s +native graphics library (e.g., \fB-lX11\fR on Linux) and your users +must be running your program in their graphical environment. Running +your program from a Linux virtual console will not work (the functions +will return -1 and set \fIerrno\fR to \fBECONNREFUSED\fR). + +.PP +What follows are descriptions of certain problems that arise with any +one supported operating system’s clipboard system. + +.SS X11 systems +.PP +The X11 clipboard system is really complex. It consists of three +so-called “selections” that can be “owned” at any time by any X +client. The owner of such a selection is responsible for serving the +requests other X clients make to him for access of the clipboard’s +content. As a consequence, \fIthe clipboard’s content is not a global +resource on X11\fR. Global is only the knowledge of the client owning +the selection. Due to this ownership system, the content of any +selection vanishes if the owner X11 connection dies (= the window +closes). + +.PP +The three selections are called \fBPRIMARY\fR, \fBSECONDARY\fR, and +\fBCLIPBOARD\fR. The first two are unique to X11 and have no +counterpart on other graphics systems; the \fBPRIMARY\fR selection can +be set in most applications by marking text with the mouse cursor, and +retrieved by pressing the middle mouse button. The \fBSECONDARY\fR +selection is not used by anybody. The \fBCLIPBOARD\fR selection is +usually accessed via pull-down menus or the well-known key +combinations \fBCTRL+C\fR and \fBCTRL+V\fR; this is the only selection +\fItinyclipboard\fR gives you access to for the sake of simplicity. It +is also the only selection that ordinary users know about. + +.PP +The \fBtiny_clipwrite()\fR and \fBtiny_clipnwrite()\fR functions on +X11 first try to communicate with a special X11 background program +called a “clipboard manager”. This is a program intended to solve the +vanishing problem indicated above; an example for such a program is +the \fBxclipboard(1)\fR application. These programs announce their +existance to the X11 server, and capable clients — like +\fBtiny_clipwrite()\fR and \fBtiny_clipnwrite()\fR — query this +information. If these functions find a clipboard manager exists, they +will write their \fItext\fR argument into the clipboard manager and +then return immediately. The clipboard manager takes over ownership of +the \fBCLIPBOARD\fR selection and from now on serves the requests of +other X clients. + +.PP +While most major X desktop environments come with a clipboard manager +program this is not necessaryly true for small desktop environments or +individual program combinations. Even experienced Linux users do not +know about the existance of a clipboard manager, and every once in a +while they wonder why their clipboard content vanishes on their own +system, while for example it doesn’t do that on a major Linux +distribution. The \fBtiny_clipwrite()\fR and \fBtiny_clipnwrite()\fR +functions thus do not give up if there is no clipboard manager +available. Instead, they call \fBfork(2)\fR to create a subprocess, +have this subprocess create an invisible X11 client window, and set +this window to be the owner of the \fBCLIPBOARD\fR selection. They +then communicate the desired content of the selection via a pipe to +the child process. Any further calls to the two functions will skip +the call to \fBfork(2)\fR if the child process still exists and instead +write the clipboard data directly onto the pipe, where the child +process notices it. When the child now receives a clipboard access +request, it replies with the current “content” of the clipboard, +i.e. the \fItext\fR argument of the last call to one of the two +functions. + +.PP +As soon as the parent process finishes or the clipboard ownership is +taken away from the child process (e.g., by hitting \fBCTRL+C\fR in +another window and thus making that window the owner of +\fBCLIPBOARD\fR), the child process exits. As the child does not +decouple from the parent process, \fBtiny_clipwrite()\fR and +\fBtiny_clipnwrite()\fR install an \fBatexit(3)\fR handler that sweeps +the process so that a zombie process is prevented. + +.SS Win32 systems +.PP +The clipboard system on Windows is modelled around a global pointer as +a resource shared between multiple applications. When an application +wants to write to the clipboard, it first opens the global clipboard +resource, excluding everybody else from accessing it (even for read +access). It then empties the clipboard, which causes the Win32 +system's OS kernel to free the previous global pointer (yes, the +pointer is freed by the kernel, not by the application). The kernel +immediately afterwards assigns ownership of the clipboard to the calling +process, which is now obleged to allocate a new buffer, store its data +in it, and hand the pointer to this buffer over to the clipboard +system. When done, the process closes the clipboard, but formally +remains owner of the clipboard until another process wants to write +into the clipboard or it exits. As far as I was able to see, this +ownership does not involve any duties if one does not use delayed +rendering (which \fItinyclipboard\fR does not do). + +.PP +Since the OS kernel manages the memory of the clipboard content, the +content does not vanish if the application closes as it does with +X11 (see above). Still, to write to the clipboard a temporary +invisible window is required, which is created by +\fBtiny_clipwrite()\fR and \fBtiny_clipnwrite()\fR on the fly and +destroyed before the functions return. This does not mean you have to +create your Win32 application as a GUI application using a +\fBWinMain()\fR function; the functions are smart enough to create +their own GUI space. They will work with both console applications and +GUI applications. + +.PP +It appears to be possible to write \fBNUL\fR bytes into the Windows +clipboard, but it is impossible to retrieve them again from there as +the clipboard functions available from the Win32API do not support +querying the size of the clipboard. They assume any text on the +clipboard is terminated with a \fBNUL\fR byte. For the sake of +portability, you should thus refrain from using \fBNUL\fR bytes in +your clipboard content if your application needs to run on Windows. + +.SH SEE ALSO +.PP +\fBtiny_clipread(3)\fR +.SH AUTHOR +.PP +The \fItinyclipboard\fR library was written by Marvin Gülker . diff --git a/man/tiny_clipread.3 b/man/tiny_clipread.3 new file mode 100644 index 0000000..8eceb2b --- /dev/null +++ b/man/tiny_clipread.3 @@ -0,0 +1,235 @@ +.\" tinyclipboard - a cross-platform C library for accessing the clipboard. +.\" +.\" Copyright © 2016 Marvin Gülker +.\" +.\" All rights reserved. See the README and LICENSE files for the +.\" licensing conditions. +.TH tiny_clipread "3" "January 2016" "Marvin Gülker" "tinyclipboard" +.SH NAME +tiny_clipread \- Read from the OS clipboard + +.SH SYNOPSIS +.nf +.B #include +.sp +.B char* tiny_clipread\fR(\fBint*\fR \fIlen\fR); + +.SH DESCRIPTION +.PP +The \fBtiny_clipread()\fR function reads arbitary data from the +operating system’s clipboard, allocates a new string by means of +\fBmalloc(3)\fR, copies the data there, and returns the newly +allocated string. In the \fIlen\fR argument it returns the number of +bytes allocated and returned. In case of failure no string is +allocated, \fBNULL\fR is returned and \fI*len\fR is left +untouched. + +.PP +The returned string is guaranteed to end with a \fBNUL\fR byte, but if +you want to handle \fBNUL\fR bytes within the clipboard data, you +should instead rely on the value returned in the \fIlen\fR +argument. If \fIlen\fR is \fBNULL\fR, the argument is ignored (and you +have to rely on the terminating \fBNUL\fR of the returned string +alone). + +.PP +The data returned is encoded in UTF-8 regardless of the current +locale’s encoding. This includes Win32 systems. + +.PP +The caller of this function is obleged to \fBfree(3)\fR the memory +returned. + +.SH RETURN VALUE +.PP +On a successful retrieval, the \fBtiny_clipread()\fR function returns +a dynamically allocated copy of the data in the operating system’s +clipboard that must be handed to \fBfree(3)\fR once you are done with +it. If the retrieval fails, the function returns \fBNULL\fR and sets +\fIerrno\fR to indicate the error. + +.SH ERRORS +.SS X11 systems +.PP +This function indicates the following errors on systems using an X11 +server for graphics management: + +.TP +.BR EAGAIN +There is no clipboard owner currently which could be queried for +anything. +.TP +.BR ECANCELED +Unexpected function failure after using an Xlib function as advertised +by a prior return value. Encountering this \fIerrno\fR value might +indicate a bug in \fItinyclipboard\fR. +.TP +.BR ECONNREFUSED +Failed to connect to the X server. This most likely means that your +program is not run from within a graphical environment (e.g., from the +Linux virtual console). +.TP +.BR ENOTSUP +The clipboard contains non-text data. +.TP +.BR EOVERFLOW +The number of bytes in the clipboard was too large to be stored in an +\fBint\fR. X11 supports much larger clipboard texts (actually +\fBunsigned long\fR bytes long ones), but \fBint\fR is the only type +that works cross-platform for all clipboard APIs and is thus the +maximum capacity supported by \fItinylcipboard\fR. + +.SS Win32 systems +.PP +This function indicates the following errors on Windows systems: + +.TP +.BR EAGAIN +Another process has opened the clipboard currently. +.TP +.BR ECANCELED +Unexpected function failure after using a Windows API function as +advertised by a prior return value. Encountering this \fIerrno\fR +value might indicate a bug in \fItinyclipboard\fR. +.TP +.BR EILSEQ +The clipboard's content was advertised as text, but was invalid +UTF-16 (in contrast to \fBENOTSUP\fR, which means the clipboard's +content was not even advertised as text). +.TP +.BR ENOTSUP +The clipboard contains non-text data. + +.SH EXAMPLES +.SS Reading a string from the clipboard +.PP +This example reads an ordinary string from the operating system’s +clipboard. + +.sp +.RS 4 +.nf +\fB +#include +#include +#include + +int main() +{ + int len = 0; + char* str = tiny_clipread(&len); + + if (str) { + printf("Read %d bytes from the clipboard: %s\\n", len, str); + } + else { + perror("Failed to read from the clipboard"); + return 1; + } + + /* Do not forget to free the returned pointer. */ + free(str); + + return 0; +} +\fR +.RE + +.SH NOTES +.PP +The clipboard is a highly operating-system specific resource. The +\fItinyclipboard\fR library strives to hide the complexities of +certain system’s clipboard systems (especially X11’s) behind a set of +simple, highlevel functions that allow the programmer to uniformly +access any supported operating system’s clipboard system. This +highlevel interface sacrifices access to some more granular features +each of the respective systems provides, but if you need these, you +should probably not be using a cross-platform clipboard library +anyway. + +.PP +Across all operating systems and graphics stacks, the +\fBtiny_clipread()\fR function does not require your application to be +a GUI application. However, it opens invisible windows to interact +with the clipboard if it is required. From this follows that while you +do not have to create your application as a GUI application, you have +to link in your system’s native graphics library (e.g., \fB-lX11\fR on +Linux) and your users must be running your program in their graphical +environment. Running your program from a Linux virtual console will +not work (the function will return -1 and set \fIerrno\fR to +\fBECONNREFUSED\fR). + +.PP +What follows are descriptions of certain problems that arise with any +one supported operating system’s clipboard system. + +.SS Unix/X11 +.PP +The X11 clipboard system is really complex. It consists of three +so-called “selections” that can be “owned” at any time by any X +client. The owner of such a selection is responsible for serving the +requests other X clients make to him for access of the clipboard’s +content. As a consequence, \fIthe clipboard’s content is not a global +resource on X11\fR. Global is only the knowledge of the client owning +the selection. Due to this ownership system, the content of any +selection vanishes if the owner X11 connection dies (= the window +closes). + +.PP +The three selections are called \fBPRIMARY\fR, \fBSECONDARY\fR, and +\fBCLIPBOARD\fR. The first two are unique to X11 and have no +counterpart on other graphics systems; the \fBPRIMARY\fR selection can +be set in most applications by marking text with the mouse cursor, and +retrieved by pressing the middle mouse button. The \fBSECONDARY\fR +selection is not used by anybody. The \fBCLIPBOARD\fR selection is +usually accessed via pull-down menus or the well-known key +combinations \fBCTRL+C\fR and \fBCTRL+V\fR; this is the only selection +\fItinyclipboard\fR gives you access to for the sake of simplicity. It +is also the only selection that ordinary users know about. + +.SS Win32 +.PP +The clipboard system on Windows is modelled around a global pointer as +a resource shared between multiple applications. When an application +wants to write to the clipboard, it first opens the global clipboard +resource, excluding everybody else from accessing it (even for read +access). It then empties the clipboard, which causes the Win32 +system's OS kernel to free the previous global pointer (yes, the +pointer is freed by the kernel, not by the application). The kernel +immediately afterwards assigns ownership of the clipboard to the calling +process, which is now obleged to allocate a new buffer, store its data +in it, and hand the pointer to this buffer over to the clipboard +system. When done, the process closes the clipboard, but formally +remains owner of the clipboard until another process wants to write +into the clipboard or it exits. As far as I was able to see, this +ownership does not involve any duties if one does not use delayed +rendering (which \fItinyclipboard\fR does not do). + +.PP +Since the OS kernel manages the memory of the clipboard content, the +content does not vanish if the application closes as it does with +X11 (see above). + +.PP +In contrast to X11 (and even \fBtiny_clipwrite(3)\fR and +\fBtiny_clipnwrite(3)\fR on Win32 systems) read access to the +clipboard does not require an (invisible) window to be created, but +merely acquiring the clipboard for a moment. On Windows, reading the +clipboard thus does not involve any GUI functionality. + +.PP +It appears to be possible to write \fBNUL\fR bytes into the Windows +clipboard, but it is impossible to retrieve them again from there as +the clipboard functions available from the Win32API do not support +querying the size of the clipboard. They assume any text on the +clipboard is terminated with a \fBNUL\fR byte. For the sake of +portability, you should thus refrain from using \fBNUL\fR bytes in +your clipboard content if your application needs to run on Windows. + +.SH SEE ALSO +.PP +.B tiny_cipwrite(3) tiny_clipnwrite(3) + +.SH AUTHOR +.PP +The \fItinyclipboard\fR library was written by Marvin Gülker . diff --git a/man/tiny_clipversion.3 b/man/tiny_clipversion.3 new file mode 100644 index 0000000..12e3a55 --- /dev/null +++ b/man/tiny_clipversion.3 @@ -0,0 +1,73 @@ +.\" tinyclipboard - a cross-platform C library for accessing the clipboard. +.\" +.\" Copyright © 2016 Marvin Gülker +.\" +.\" All rights reserved. See the README and LICENSE files for the +.\" licensing conditions. +.TH tiny_clipversion "3" "January 2016" "Marvin Gülker" "tinyclipboard" +.SH NAME +tiny_clipversion \- tinyclipboard version information + +.SH SYNOPSIS +.nf +.B #include +.sp +.B #define TINYCLIPBOARD_VERSION +.sp +.B const char* tiny_clipversion\fR(\fBvoid\fR); + +.SH DESCRIPTION +.PP +The \fBtiny_clipversion()\fR function gives information about the +version of the \fItinyclipboard\fR library in use, condensed into one +string. + +.PP +The \fBTINYCLIPBOARD_VERSION\fR macro provides the same information, +but separated into components you can check against. It is defined as +the version number as an ordinary number of form \fBYYYYMMPPL\fR, +where \fBYYYY\fR denotes the year, \fBMM\fR denotes the month (with a +leading zero if it is a month < 10), \fBPP\fR denotes the patch +release number (again with a leading zero or even with two zeros for +the first release in a month) and \fBL\fR is literal (i.e. denotes a +\fBlong int\fR constant value). For example, it may have the value +\fB20160100L\fR, which means the release was made in January 2016, and +it was the first of any releases in January. If it had the value +\fB20160101L\fR, then it would be the second release in January 2016. + +.SH RETURN VALUE +.PP +This function returns a pointer to statically allocated memory that +contains the version information as a \fBNUL\fR-terminated string that +does not end with a newline. It must not be freed. + +.PP +The macro is defined as a literal constant of type \fBlong int\fR. + +.SH ERRORS +.PP +None. + +.SH EXAMPLES +.PP +None. + +.SH NOTES +.PP +The \fItinyclipboard\fR library follows a simplistic versioning +scheme that is mostly based on the release date. The version number is +of form \fBYY.MM\fR, which refers to the shorted year and the number +of the month the release was made in. If multiple releases are made in +the same month, the version number becomes \fBYY.MM.PP\fR, where +\fBPP\fR is the number of the followup release (\fBPP\fR can never be +zero, as it then falls off). \fBPP\fR has no leading zeros, but +\fBMM\fR has. Note that it it rather unlikely that I do more than nine +releases in a month. + +.SH SEE ALSO +.PP +None. + +.SH AUTHOR +.PP +The \fItinyclipboard\fR library was written by Marvin Gülker . diff --git a/man/tiny_clipwrite.3 b/man/tiny_clipwrite.3 new file mode 100644 index 0000000..205aba2 --- /dev/null +++ b/man/tiny_clipwrite.3 @@ -0,0 +1,23 @@ +.\" tinyclipboard - a cross-platform C library for accessing the clipboard. +.\" +.\" Copyright © 2016 Marvin Gülker +.\" +.\" All rights reserved. See the README and LICENSE files for the +.\" licensing conditions. +.TH tiny_clipwrite "3" "January 2016" "Marvin Gülker" "tinyclipboard" +.SH NAME +tiny_clipwrite \- Write a string to the OS clipboard + +.SH SYNOPSIS +.nf +.B #include +.sp +.B int tiny_clipwrite\fR(\fBconst char*\fR \fItext\fR); + +.SH DESCRIPTION +.PP +Refer to \fBtiny_clipnwrite(3)\fR. + +.SH AUTHOR +.PP +The \fItinyclipboard\fR library was written by Marvin Gülker . diff --git a/src/tinyclipboard.c b/src/tinyclipboard.c new file mode 100755 index 0000000..e7baa06 --- /dev/null +++ b/src/tinyclipboard.c @@ -0,0 +1,785 @@ +/* tinyclipboard - a cross-platform C library for accessing the clipboard. + * + * Copyright © 2016 Marvin Gülker + * + * All rights reserved. See the README and LICENSE files for the + * licensing conditions. + */ + +#include +#include +#include +#include +#include +#include + +#if defined(__unix__) +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Helper variables */ +static pid_t s_cb_pid = 0; +static Window s_clipowner_window = None; + +/* Helper functions */ +static void finish_subprocess_on_exit(void); +static void child_handle_sigint(int); +static void own_x11_clipboard(int filedes); +static void handle_x11_selectionrequest(Display* p_display, XEvent evt, const char* cliptext, int textlen); +static bool write_to_clipboard_manager(const char* cliptext, int len); +static void get_clipboard_text(int filedes, char** p_str, int* p_len); + +#elif defined(_WIN32) +#define WINVER 0x0600 /* >= Windows Vista */ +#include + +/* Helper functions */ +LRESULT Win32MessageHandler(HWND window, UINT message, WPARAM wparam, LPARAM lparam); +#else +#error Dont know how to access the clipboard on this OS! +#endif + +#include "../include/tinyclipboard.h" + +/* + * Resources: + * - https://stackoverflow.com/questions/10570315/clipboard-selection-transfer-does-not-work + * - https://web.archive.org/web/20120923013354/http://michael.toren.net/mirrors/doc/X-copy+paste.txt + * - https://github.com/Quintus/imitator/blob/master/imitator_x/ext/clipboard.c + * - https://wiki.archlinux.org/index.php/Clipboard + * - https://wiki.freedesktop.org/www/ClipboardManager/ + * - http://www.x.org/docs/ICCCM/icccm.pdf + * - xclip(1) sources + * + * - https://msdn.microsoft.com/en-us/library/windows/desktop/aa383745%28v=vs.85%29.aspx + * - https://msdn.microsoft.com/en-us/library/windows/desktop/dd374131%28v=vs.85%29.aspx + * - https://msdn.microsoft.com/en-us/library/windows/desktop/dd374130%28v=vs.85%29.aspx + * - https://msdn.microsoft.com/en-us/library/windows/desktop/ms648709%28v=vs.85%29.aspx + */ + +/**************************************** + * Public API + ***************************************/ + +char* tiny_clipread(int* len) +{ +#if defined(__unix__) + Display* p_display = NULL; + Window window = None; + XEvent evt; + Atom clipboard; + Atom utf8; + Atom store_prop; + + p_display = XOpenDisplay(NULL); + if (!p_display) { + errno = ECONNREFUSED; + return NULL; + } + + /* Allocate atoms */ + clipboard = XInternAtom(p_display, "CLIPBOARD", False); /* CLIPBOARD is the atom for the win32-like clipboard */ + utf8 = XInternAtom(p_display, "UTF8_STRING", True); /* Resource for UTF-8 text */ + store_prop = XInternAtom(p_display, "TINYCLIP_STORE", False); /* Our custom window property for storage */ + + /* Check if there is a clipboard owner that can answer me */ + if (XGetSelectionOwner(p_display, clipboard) == None) { + XCloseDisplay(p_display); + errno = EAGAIN; + return NULL; + } + + /* Request selection content */ + window = XCreateSimpleWindow(p_display, XDefaultRootWindow(p_display), 0, 0, 1, 1, 0, 0, 0); + XConvertSelection(p_display, clipboard, utf8, store_prop, window, CurrentTime); + + /* X11 will send us a SelectionNotify event when the result + * is available from the owner. */ + for(;;) { + XNextEvent(p_display, &evt); + if (evt.type == SelectionNotify) { + break; + } + } + + /* property is None here if the owner is unable to convert the + * selection to the requested format (UTF-8 text). */ + if (evt.xselection.property == None) { + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + errno = ENOTSUP; + return NULL; + } + else { + Atom actual_type; + int actual_format = 0; + unsigned long nitems = 0; + unsigned long bytes_left = 0; + int bytes = 0; + unsigned char* property = NULL; + char* outbuf = NULL; + + /* Get the length of the data that was stored in our property. */ + if (XGetWindowProperty(p_display, window, store_prop, + 0, 0, False, + AnyPropertyType, &actual_type, &actual_format, + &nitems, &bytes_left, &property) != Success) { + /* In theory, we should never get here */ + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + errno = ECANCELED; + return NULL; + } + + /* I need to constrain to int as the largest common type */ + if (bytes_left + 1 > INT_MAX) { + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + errno = EOVERFLOW; + return NULL; + } + + /* Prepare return buffer (with terminating NUL) */ + outbuf = (char*) calloc(bytes_left + 1, sizeof(char)); + bytes = (int) bytes_left; /* INT_MAX checked above */ + + /* Retrieval requested with enough space */ + if (XGetWindowProperty(p_display, window, store_prop, + 0, bytes_left /* / 8 ?? */, False, + AnyPropertyType, &actual_type, &actual_format, + &nitems, &bytes_left, &property) != Success) { + /* In theory, we should never get here */ + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + errno = ECANCELED; + return NULL; + } + + /* Copy the data (note `bytes_left' is 0 here, hence I use `bytes', + * which was set above). */ + strncpy(outbuf, (char*)property, bytes); + if (len) + *len = bytes; + + /* Cleanup */ + XFree(property); + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + + /* Finish */ + return outbuf; + } +#elif defined(_WIN32) + HGLOBAL global_handle = NULL; + LPWSTR cliptext = NULL; + int bufsize = 0; + char* outbuf = NULL; + + if (!IsClipboardFormatAvailable(CF_UNICODETEXT)) { + /* Unsupported data format */ + errno = ENOTSUP; + return NULL; + } + if (!OpenClipboard(NULL)) { + /* Another application has the clipboard open */ + errno = EAGAIN; + return NULL; + } + + global_handle = GetClipboardData(CF_UNICODETEXT); + if (!global_handle) { + /* Clipboard owner lied before and has no unicode data */ + CloseClipboard(); + errno = ENOTSUP; + return NULL; + } + + cliptext = GlobalLock(global_handle); + bufsize = WideCharToMultiByte(CP_UTF8, 0, cliptext, -1, NULL, 0, NULL, NULL); + if (!bufsize) { + /* There was invalid UTF-16 on the clipboard */ + GlobalUnlock(global_handle); + CloseClipboard(); + errno = EILSEQ; + return NULL; + } + + outbuf = calloc(bufsize, 1); + bufsize = WideCharToMultiByte(CP_UTF8, 0, cliptext, -1, outbuf, bufsize, NULL, NULL); + if (!bufsize) { + /* This should not happen in theory */ + free(outbuf); + GlobalUnlock(global_handle); + CloseClipboard(); + errno = ECANCELED; + return NULL; + } + + /* Cleanup */ + GlobalUnlock(global_handle); + CloseClipboard(); + + if (len) + *len = bufsize; + + return outbuf; +#else +#error Dont know how to read the clipboard on this platform! +#endif +} + +int tiny_clipnwrite(const char* text, int len) +{ +#if defined(__unix__) + static unsigned short tries = 0; + static int pipefds[2]; + static int has_registered_exit_handler = 0; + Display* p_display = XOpenDisplay(NULL); + + if (!p_display) { /* No X11 server running */ + errno = ECONNREFUSED; + return -1; + } + else { + XCloseDisplay(p_display); + } + + /* If a clipboard manager can take over, we do not do all this + * hard fork() work and simply have it serve the content. */ + if (write_to_clipboard_manager(text, len)) + return 0; + + if (!s_cb_pid) { /* No clipboard handler process has been spawned yet. Do it now. */ + if (tries++ > 3) { + /* 3 times in a row failed while recursing, + * fail finally to prevent endless recursion. */ + tries = 0; + errno = ECHILD; + return -1; + } + + /* Create child communication pipe */ + if (pipe(pipefds) < 0) { + errno = EPIPE; + return -1; + } + + /* I don't want this pipe to block; see get_clipboard_text(). */ + fcntl(pipefds[0], F_SETFL, O_NONBLOCK); + + switch(s_cb_pid = fork()) { /* single = intended */ + case -1: + /* fork failed, clean things up. */ + s_cb_pid = 0; + close(pipefds[0]); + close(pipefds[1]); + errno = ECHILD; + return -1; + case 0: /* child */ + /* Close pipe ending we do not use */ + close(pipefds[1]); + + /* Loop */ + signal(SIGINT, child_handle_sigint); + own_x11_clipboard(pipefds[0]); + + /* Cleanup and exit */ + close(pipefds[0]); + exit(0); + return 0; /* not reached */ + default: /* parent */ + /* Close pipe ending we do not use */ + close(pipefds[0]); + + /* Register our friendly process killer exactly once. */ + if (!has_registered_exit_handler) { + atexit(finish_subprocess_on_exit); + has_registered_exit_handler = 1; + } + + /* Recurse so we reach the other if branch */ + return tiny_clipnwrite(text, len); + } + } + else { /* Existing clipboard handler process */ + if (waitpid(s_cb_pid, NULL, WNOHANG) != 0) { + /* Child process died, recreate it */ + s_cb_pid = 0; + close(pipefds[1]); + + return tiny_clipnwrite(text, len); + } + else { /* Process is still alive */ + /* Write length and text into the child process */ + write(pipefds[1], &len, sizeof(int)); /* yes, raw byte value! */ + write(pipefds[1], text, len); + + tries = 0; /* Reset process death counter */ + return 0; + } + } +#elif defined(_WIN32) + HWND window = NULL; + HGLOBAL global_handle; + LPWSTR cliptext_utf16; + int charcount; + MSG message; + BOOL result; + static bool class_registered = false; + + /* Register our window class only on the first call */ + if (!class_registered) { + WNDCLASSEXW windowclass; + memset(&windowclass, '\0', sizeof(WNDCLASSEX)); + + windowclass.cbSize = sizeof(WNDCLASSEX); + windowclass.lpfnWndProc = (WNDPROC) Win32MessageHandler; + windowclass.lpszClassName = L"TinyClipboardWindowClass"; + + if (RegisterClassExW(&windowclass)) { + class_registered = true; + } + else { + errno = ENOTSUP; + return -1; + } + } + + window = CreateWindowW(L"TinyClipboardWindowClass", L"TinyClipboard window", + 0, CW_USEDEFAULT, + CW_USEDEFAULT, CW_USEDEFAULT, + CW_USEDEFAULT, NULL, NULL, + NULL, NULL); + if (!window) { + errno = ENOTSUP; + return -1; + } + + UpdateWindow(window); + + /* Acquire clipboard ownership. */ + if (!OpenClipboard(window)) { + DestroyWindow(window); + errno = EAGAIN; + return -1; + } + EmptyClipboard(); + + /* Determine size of this in UTF-16 */ + charcount = MultiByteToWideChar(CP_UTF8, 0, text, (int) len, NULL, 0); + if (!charcount) { + /* User passed invalid UTF-8 */ + CloseClipboard(); + DestroyWindow(window); + errno = EINVAL; + return -1; + } + + /* Allocate system-global memory chunk. */ + global_handle = GlobalAlloc(GMEM_MOVEABLE, charcount * sizeof(WCHAR) + 2); /* Terminating UTF-16 NUL-NUL */ + cliptext_utf16 = GlobalLock(global_handle); + + /* Write string as UTF-16 into the clipboard. */ + memset(cliptext_utf16, '\0', charcount * sizeof(WCHAR) + 2); + charcount = MultiByteToWideChar(CP_UTF8, 0, text, (int) len, cliptext_utf16, charcount); + if (!charcount) { + GlobalFree(global_handle); /* probably includes GlobalUnlock() */ + CloseClipboard(); + DestroyWindow(window); + errno = EINVAL; + return -1; + } + + /* Hand the pointer over to the OS, which will take care + * of freeing it and detaching it from this process so + * that is stays around even after the application has + * closed. */ + if(!SetClipboardData(CF_UNICODETEXT, global_handle)) { + /* This should not happen. */ + GlobalFree(global_handle); + CloseClipboard(); + DestroyWindow(window); + errno = ECANCELED; + return -1; + } + + /* Cleanup */ + GlobalUnlock(global_handle); + CloseClipboard(); + + /* Tell the window to properly exit */ + PostMessageW(window, WM_CLOSE, 0, 0); + + /* Main loop */ + while ((result = GetMessageW(&message, NULL, 0, 0)) != 0) { + if (result == -1) { + /* Very interesting. GetMessage() docs indicate that a BOOL + * type can actually be one of three values: -1, 0, nonzero. + * What was exactly the purpose of a BOOL then? */ + DestroyWindow(window); + errno = ECANCELED; + return -1; + } + + TranslateMessage(&message); + DispatchMessageW(&message); + } + + return 0; +#else +#error Dont know how to access the clipboard on this system! +#endif +} + +int tiny_clipwrite(const char* text) +{ + return tiny_clipnwrite(text, strlen(text)); +} + +const char* tiny_clipversion() +{ + static char buf[512]; + int year = TINYCLIPBOARD_VERSION / 10000L; + int month = (TINYCLIPBOARD_VERSION - year * 10000L) / 100L; + int day = (TINYCLIPBOARD_VERSION - year * 10000L) - month * 100L; + + if (day) { + sprintf(buf, + "tinyclipboard %d.%02d.%d%s, copyright © %d Marvin Gülker. This is free software distributed under the terms of the GNU GPLv3 license.", + year % 100, + month, + day, + TINYCLIPBOARD_VERSION_POSTFIX, + year); + } + else { + sprintf(buf, + "tinyclipboard %d.%02d%s, copyright © %d Marvin Gülker. This is free software distributed under the terms of the GNU GPLv3 license.", + year % 100, + month, + TINYCLIPBOARD_VERSION_POSTFIX, + year); + } + + return buf; +} + + +/**************************************** + * Private helpers for X11 + ***************************************/ + +#ifdef __unix__ +void finish_subprocess_on_exit(void) +{ + if (s_cb_pid) { + /* Initiate civilised shutdown in clipboard owner process. */ + kill(s_cb_pid, SIGINT); + waitpid(s_cb_pid, NULL, 0); + } + + /* FIXME: Does not close parent process' pipe ending. This + * should be done here. But hey, we are exiting anyway, and + * this way I don't need an extra file-static variable... */ +} + +/* Initiates cililised shutdown by closing the clipboard owner window + * (which generates a DestroyNotify event; see XDestroyWindowEvent(3)). + * If that fails for whatever reason, calls exit() directly. + */ +void child_handle_sigint(int signum) +{ + Display* p_display = NULL; + + /* Exit immediately if there is no window to clean up + * (which should never be the case). */ + if (s_clipowner_window == None) + exit(2); + + if ((p_display = XOpenDisplay(NULL))) { /* Single = intended */ + XDestroyWindow(p_display, s_clipowner_window); + XCloseDisplay(p_display); + /* Main code will exit() instead of us */ + } + else { + /* No X11 connection, but we are on shutdown. Emergency shutdown. */ + exit(2); + } +} + +void get_clipboard_text(int filedes, char** p_str, int* p_len) +{ + ssize_t ret = 0; + + /* Attempt to read one ulong from the pipe. Note it has O_NONBLOCK set! */ + ret = read(filedes, p_len, sizeof(int)); /* raw byte read */ + if (ret < 0 && errno == EAGAIN) + return; /* Reading would block, i.e. no new clipboard data available */ + else if (ret < 0 || (ret != sizeof(int))) + goto fail; /* Transfer protocol violated */ + + /* Allocate space for the number of bytes advertised. */ + *p_str = realloc(*p_str, *p_len + 1); + memset(*p_str, '\0', *p_len + 1); /* For extra safety */ + + /* Read advertised bytes from the pipe. */ + ret = read(filedes, *p_str, *p_len); + if (ret <= 0 || (ret != *p_len)) + goto fail; /* Transfer protocol violated */ + + return; + + fail: + fprintf(stderr, "**tinyclipboard: Parent process violated transfer protocol, discarding. This is likely a bug.\n"); + free(*p_str); + *p_str = NULL; + *p_len = 0; +} + +void own_x11_clipboard(int filedes) +{ + Display* p_display = NULL; + char* cliptext = NULL; + int textlen = 0; + int terminate = 0; + Atom clipboard; + + p_display = XOpenDisplay(NULL); + if (!p_display) { + fprintf(stderr, "**tinyclipboard: Failed to open X11 display connection.\n"); + exit(1); + return; + } + + s_clipowner_window = XCreateSimpleWindow(p_display, XDefaultRootWindow(p_display), 0, 0, 1, 1, 0, 0, 0); + + /* Tell X.org we want to receive the DestroyNotify event; see + * - https://tronche.com/gui/x/xlib/events/window-state-change/destroy.html + * - http://www.lemoda.net/c/xlib-resize/ */ + XSelectInput(p_display, s_clipowner_window, StructureNotifyMask); + + /* Own CLIPBOARD (= win32-like clipboard) */ + clipboard = XInternAtom(p_display, "CLIPBOARD", False); + XSetSelectionOwner(p_display, clipboard, s_clipowner_window, CurrentTime); + + if (XGetSelectionOwner(p_display, clipboard) != s_clipowner_window) { + fprintf(stderr, "**tinyclipboard: Failed to obtain ownership of X11 CLIPBOARD clipboard.\n"); + exit(1); + } + + /* Main loop */ + while (!terminate) { + XEvent evt; + XNextEvent(p_display, &evt); /* blocks if no events available */ + + switch(evt.type) { + case SelectionRequest: + get_clipboard_text(filedes, &cliptext, &textlen); + handle_x11_selectionrequest(p_display, evt, cliptext, textlen); + break; + case SelectionClear: /* We are no longer CLIPBOARD owner */ + XDestroyWindow(p_display, s_clipowner_window); + break; + case DestroyNotify: /* X11 killed the window */ + s_clipowner_window = None; + terminate = 1; + break; + default: + break; /* Ignore unsupported event */ + } + } + + free(cliptext); +} + +void handle_x11_selectionrequest(Display* p_display, XEvent evt, const char* cliptext, int textlen) +{ + Atom utf8 = XInternAtom(p_display, "UTF8_STRING", True); /* Resource for UTF-8 text */ + Atom targets = XInternAtom(p_display, "TARGETS", True); /* Query for available types */ + Atom save_targets = XInternAtom(p_display, "SAVE_TARGETS", False); /* No-op marker atom for clipmanagers */ + XEvent response; + + response.xselection.type = SelectionNotify; + response.xselection.display = evt.xselectionrequest.display; + response.xselection.requestor = evt.xselectionrequest.requestor; + response.xselection.selection = evt.xselectionrequest.selection; + response.xselection.target = evt.xselectionrequest.target; + response.xselection.time = evt.xselectionrequest.time; + + if (textlen > 0 && (evt.xselectionrequest.target == targets)) { /* Request for supported clipboard targets (we only supported text) */ + Atom supported_targets[] = {utf8, XA_STRING, save_targets}; + response.xselection.property = evt.xselectionrequest.property; + XChangeProperty(p_display, + evt.xselectionrequest.requestor, + evt.xselectionrequest.property, + evt.xselectionrequest.target, /* 'targets' atom */ + 8, + PropModeReplace, + (unsigned char*)(&supported_targets), + sizeof(supported_targets)); + } + else if (textlen > 0 && evt.xselectionrequest.target == save_targets) { + /* This is a No-op target as per freedesktop.org spec. */ + response.xselection.property = None; + } + else if (textlen > 0 && evt.xselectionrequest.target == utf8) { /* Request for real text content, UTF-8 requested */ + response.xselection.property = evt.xselectionrequest.property; + XChangeProperty(p_display, + evt.xselectionrequest.requestor, + evt.xselectionrequest.property, + evt.xselectionrequest.target, /* 'utf8' atom */ + 8, + PropModeReplace, + (unsigned char*)cliptext, + textlen); + } + else if (textlen > 0 && evt.xselectionrequest.target == XA_STRING) { /* Request for locale-dependant encoded text -- UNTESTED with non-utf8-locales*/ + const char* locale_encoding = nl_langinfo(CODESET); + iconv_t converter = iconv_open(locale_encoding, "UTF-8"); + char* source_string = (char*) cliptext; /* remove 'const' -- we do not change it, but the function prototype is broken */ + size_t bytes_allocated = 32; + char* target_string = (char*) calloc(bytes_allocated, 1); + char* outbuf = target_string; + size_t inbytesleft = textlen; + size_t outbytesleft = bytes_allocated; + + /* Convert from UTF-8 to locale's encoding. */ + while (inbytesleft > 0) { + if (iconv(converter, &source_string, &inbytesleft, &outbuf, &bytes_allocated) == ((size_t)-1)) { + if (errno == E2BIG) { + target_string = (char*) realloc(target_string, bytes_allocated + 32); + memset(target_string + bytes_allocated, '\0', 32); + + outbuf = target_string + bytes_allocated - outbytesleft; + + bytes_allocated += 32; + outbytesleft += 32; + } + else { + perror("**tinyclipboard: Failed to convert string into locale encoding"); + response.xselection.property = None; + XSendEvent(p_display, evt.xselectionrequest.requestor, 0, 0, &response); + iconv_close(converter); + free(target_string); + return; + } + } + } + + /* The following is the same as with utf8 above, just with another charset. */ + response.xselection.property = evt.xselectionrequest.property; + XChangeProperty(p_display, + evt.xselectionrequest.requestor, + evt.xselectionrequest.property, + evt.xselectionrequest.target, /* XA_STRING atom */ + 8, + PropModeReplace, + (unsigned char*)target_string, + bytes_allocated - outbytesleft); + + iconv_close(converter); + free(target_string); + } + else { /* Unsupported target requested or textlen <= 0 (i.e. empty clipboard) */ + response.xselection.property = None; + } + + XSendEvent(p_display, evt.xselectionrequest.requestor, 0, 0, &response); +} + +bool write_to_clipboard_manager(const char* cliptext, int len) +{ + Display* p_display = NULL; + Window window = None; + Atom clipboard_manager; + Atom clipboard; + Atom save_targets; + bool terminate = false; + bool result = false; + + p_display = XOpenDisplay(NULL); + if (!p_display) + return false; + + clipboard = XInternAtom(p_display, "CLIPBOARD", False); + clipboard_manager = XInternAtom(p_display, "CLIPBOARD_MANAGER", False); + save_targets = XInternAtom(p_display, "SAVE_TARGETS", False); + + /* Check if a clipboard manager is available. If not, we cannot write + * to it. */ + if (XGetSelectionOwner(p_display, clipboard_manager) == None) { + XCloseDisplay(p_display); + return false; + } + + /* Own CLIPBOARD */ + window = XCreateSimpleWindow(p_display, XDefaultRootWindow(p_display), 0, 0, 1, 1, 0, 0, 0); + XSetSelectionOwner(p_display, clipboard, window, CurrentTime); + + /* Notify CLIPBOARD_MANAGER we want it to take over. */ + XConvertSelection(p_display, clipboard_manager, save_targets, None, window, CurrentTime); + + /* Main loop */ + while (!terminate) { + XEvent evt; + XNextEvent(p_display, &evt); /* blocks if no events available */ + + switch(evt.type) { + case SelectionRequest: + /* Take advantage of existing handler function. */ + handle_x11_selectionrequest(p_display, evt, cliptext, len); + break; + case SelectionClear: /* We are no longer owner; a 3rd party took over. */ + terminate = true; + result = true; /* 3rd party superseded us; do not write to clipboard anymore */ + break; + case SelectionNotify: + /* If Clipboard manager is done. */ + if (evt.xselection.target == save_targets) { + terminate = true; + result = evt.xselection.property == None; /* Check wheather clipboard managers failed. */ + } + break; + default: + break; /* Ignore unknown events */ + } + } + + XDestroyWindow(p_display, window); + XCloseDisplay(p_display); + return result; +} + +#endif + +/**************************************** + * Private helpers for Win32 + ***************************************/ + +#ifdef _WIN32 +LRESULT Win32MessageHandler(HWND window, UINT message, WPARAM wparam, LPARAM lparam) +{ + switch(message) { + case WM_NCCREATE: + return TRUE; + case WM_CREATE: + return 0; + case WM_CLOSE: + DestroyWindow(window); + return 0; + case WM_DESTROY: + PostQuitMessage(0); + default: + /* Do not process event by default */ + return -1; + } +} +#endif