SQLITECPP_IN_EXTENSION option controlling linking and use of sqlite3e…

…xt.h

CMakeLists.txt

@@ -233,7 +233,13 @@ endif ()
 ## Build provided copy of SQLite3 C library ##
 
 option(SQLITECPP_INTERNAL_SQLITE "Add the internal SQLite3 source to the project." ON)
-if (SQLITECPP_INTERNAL_SQLITE)
+option(SQLITECPP_IN_EXTENSION "Use SQLiteCpp in the implementation of a SQLite3 loadable extension" OFF)
+if(SQLITECPP_IN_EXTENSION)
+    # To use within a SQLite3 loadable extension, we must not target_link_libraries() SQLite3 itself; the
+    # host program will already have loaded it (possibly a statically-linked version) and we'll receive its
+    # API pointers via sqlite3_extension_init().
+    target_compile_definitions(SQLiteCpp PUBLIC SQLITECPP_IN_EXTENSION)
+elseif (SQLITECPP_INTERNAL_SQLITE)
     message(STATUS "Compile sqlite3 from source in subdirectory")
     option(SQLITE_ENABLE_JSON1 "Enable JSON1 extension when building internal sqlite3 library." ON)
     # build the SQLite3 C library (for ease of use/compatibility) versus Linux sqlite3-dev package
@@ -285,7 +291,7 @@ else (SQLITECPP_INTERNAL_SQLITE)
             target_link_libraries(SQLiteCpp PRIVATE ${sqlcipher_LIBRARY})
         endif()
     endif()
-endif (SQLITECPP_INTERNAL_SQLITE)
+endif (SQLITECPP_IN_EXTENSION)
 
 # Link target with pthread and dl for Unix
 if (UNIX)

src/Backup.cpp

@@ -13,7 +13,12 @@
 
 #include <SQLiteCpp/Exception.h>
 
+#if !defined(SQLITECPP_IN_EXTENSION) || defined(SQLITE_CORE)
 #include <sqlite3.h>
+#else
+#include <sqlite3ext.h>
+extern "C" const sqlite3_api_routines *sqlite3_api;
+#endif
 
 namespace SQLite
 {

src/Column.cpp

@@ -10,7 +10,12 @@
  */
 #include <SQLiteCpp/Column.h>
 
+#if !defined(SQLITECPP_IN_EXTENSION) || defined(SQLITE_CORE)
 #include <sqlite3.h>
+#else
+#include <sqlite3ext.h>
+extern "C" const sqlite3_api_routines *sqlite3_api;
+#endif
 
 #include <iostream>
 

src/Database.cpp

@@ -15,7 +15,13 @@
 #include <SQLiteCpp/Exception.h>
 #include <SQLiteCpp/Statement.h>
 
+#if !defined(SQLITECPP_IN_EXTENSION) || defined(SQLITE_CORE)
 #include <sqlite3.h>
+#else
+#include <sqlite3ext.h>
+extern "C" const sqlite3_api_routines *sqlite3_api;
+#endif
+
 #include <fstream>
 #include <string.h>
 

src/Exception.cpp

@@ -10,7 +10,12 @@
  */
 #include <SQLiteCpp/Exception.h>
 
+#if !defined(SQLITECPP_IN_EXTENSION) || defined(SQLITE_CORE)
 #include <sqlite3.h>
+#else
+#include <sqlite3ext.h>
+extern "C" const sqlite3_api_routines *sqlite3_api;
+#endif
 
 
 namespace SQLite

src/Statement.cpp

@@ -15,7 +15,12 @@
 #include <SQLiteCpp/Assertion.h>
 #include <SQLiteCpp/Exception.h>
 
+#if !defined(SQLITECPP_IN_EXTENSION) || defined(SQLITE_CORE)
 #include <sqlite3.h>
+#else
+#include <sqlite3ext.h>
+extern "C" const sqlite3_api_routines *sqlite3_api;
+#endif
 
 namespace SQLite
 {