From 468b9af4cc5dbc21805f0bd01247d11321ba8450 Mon Sep 17 00:00:00 2001
From: Andy Caldwell <andycaldwell@microsoft.com>
Date: Thu, 29 Dec 2022 17:02:52 +0000
Subject: [PATCH] chore(ffi): Revamp `gen_header` using `cargo-expand` (#3092)

---
 .github/workflows/CI.yml | 14 +++----
 capi/cbindgen.toml       |  5 +--
 capi/gen_header.sh       | 89 ++++++++--------------------------------
 capi/include/hyper.h     |  1 +
 4 files changed, 25 insertions(+), 84 deletions(-)

diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 4ce4f5f66e..f08af14d75 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -167,12 +167,6 @@ jobs:
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
 
-      - name: Install cbindgen
-        uses: actions-rs/cargo@v1
-        with:
-          command: install
-          args: cbindgen
-
       - name: Build FFI
         uses: actions-rs/cargo@v1
         env:
@@ -190,7 +184,7 @@ jobs:
           RUSTFLAGS: --cfg hyper_unstable_ffi
         with:
           command: test
-          args: --features full,ffi --lib
+          args: --features server,client,http1,http2,ffi --lib
 
   ffi-header:
     name: Verify hyper.h is up to date
@@ -208,6 +202,12 @@ jobs:
           command: install
           args: cbindgen
 
+      - name: Install cargo-expand
+        uses: actions-rs/cargo@v1
+        with:
+          command: install
+          args: cargo-expand
+
       - name: Build FFI
         uses: actions-rs/cargo@v1
         env:
diff --git a/capi/cbindgen.toml b/capi/cbindgen.toml
index d1a58234b5..615df080f6 100644
--- a/capi/cbindgen.toml
+++ b/capi/cbindgen.toml
@@ -7,9 +7,6 @@ header = """/*
  */"""
 include_guard = "_HYPER_H"
 no_includes = true
-sys_includes = ["stdint.h", "stddef.h"]
+sys_includes = ["stdint.h", "stddef.h", "stdbool.h"]
 cpp_compat = true
 documentation_style = "c"
-
-[parse.expand]
-crates = ["hyper-capi"]
diff --git a/capi/gen_header.sh b/capi/gen_header.sh
index d0b9c13a32..7a08d3e6ff 100755
--- a/capi/gen_header.sh
+++ b/capi/gen_header.sh
@@ -6,101 +6,44 @@
 set -e
 
 CAPI_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-
-WORK_DIR=$(mktemp -d)
-
-# check if tmp dir was created
-if [[ ! "$WORK_DIR" || ! -d "$WORK_DIR" ]]; then
-    echo "Could not create temp dir"
-    exit 1
-fi
-
 header_file_backup="$CAPI_DIR/include/hyper.h.backup"
 
 function cleanup {
-    rm -rf "$WORK_DIR"
+    rm -rf "$WORK_DIR" || true
     rm "$header_file_backup" || true
 }
 
 trap cleanup EXIT
 
-mkdir "$WORK_DIR/src"
-
-# Fake a library
-cat > "$WORK_DIR/src/lib.rs" << EOF
-#[path = "$CAPI_DIR/../src/ffi/mod.rs"]
-pub mod ffi;
-EOF
-
-# And its Cargo.toml
-cat > "$WORK_DIR/Cargo.toml" << EOF
-[package]
-name = "hyper"
-version = "0.0.0"
-edition = "2018"
-publish = false
-
-[dependencies]
-# Determined which dependencies we need by running the "cargo rustc" command
-# below and watching the compile error output for references to unknown imports,
-# until we didn't get any errors.
-bytes = "1"
-futures-channel = "0.3"
-futures-util = { version = "0.3", default-features = false, features = ["alloc"] }
-libc = { version = "0.2", optional = true }
-http = "0.2"
-http-body = "0.4"
-tokio = { version = "1", features = ["rt"] }
-
-[features]
-default = [
-    "client",
-    "ffi",
-    "http1",
-]
+WORK_DIR=$(mktemp -d)
 
-http1 = []
-client = []
-ffi = ["libc", "tokio/rt"]
-EOF
+# check if tmp dir was created
+if [[ ! "$WORK_DIR" || ! -d "$WORK_DIR" ]]; then
+    echo "Could not create temp dir"
+    exit 1
+fi
 
 cp "$CAPI_DIR/include/hyper.h" "$header_file_backup"
 
-#cargo metadata --no-default-features --features ffi --format-version 1 > "$WORK_DIR/metadata.json"
-
-cd "${WORK_DIR}" || exit 2
-
 # Expand just the ffi module
-if ! output=$(RUSTFLAGS='--cfg hyper_unstable_ffi' cargo rustc -- -Z unpretty=expanded 2>&1 > expanded.rs); then
-    # As of April 2021 the script above prints a lot of warnings/errors, and
-    # exits with a nonzero return code, but hyper.h still gets generated.
-    #
-    # However, on Github Actions, this will result in automatic "annotations"
-    # being added to files not related to a PR, so if this is `--verify` mode,
-    # then don't show it.
-    #
-    # But yes show it when using it locally.
-    if [[ "--verify" != "$1" ]]; then
-        echo "$output"
-    fi
+if ! RUSTFLAGS='--cfg hyper_unstable_ffi' cargo expand --features client,http1,http2,ffi ::ffi 2> $WORK_DIR/expand_stderr.err > $WORK_DIR/expanded.rs; then
+    cat $WORK_DIR/expand_stderr.err
 fi
 
-# Replace the previous copy with the single expanded file
-rm -rf ./src
-mkdir src
-mv expanded.rs src/lib.rs
-
-
 # Bindgen!
 if ! cbindgen \
     --config "$CAPI_DIR/cbindgen.toml" \
     --lockfile "$CAPI_DIR/../Cargo.lock" \
     --output "$CAPI_DIR/include/hyper.h" \
-    "${@}"; then
+    "${@}"\
+    $WORK_DIR/expanded.rs 2> $WORK_DIR/cbindgen_stderr.err; then
     bindgen_exit_code=$?
     if [[ "--verify" == "$1" ]]; then
-        echo "diff generated (<) vs backup (>)"
-        diff "$CAPI_DIR/include/hyper.h" "$header_file_backup"
+        echo "Changes from previous header (old < > new)"
+        diff -u "$header_file_backup" "$CAPI_DIR/include/hyper.h"
+    else
+        echo "cbindgen failed:"
+        cat $WORK_DIR/cbindgen_stderr.err
     fi
     exit $bindgen_exit_code
 fi
diff --git a/capi/include/hyper.h b/capi/include/hyper.h
index d41ccaaccd..591cb9771c 100644
--- a/capi/include/hyper.h
+++ b/capi/include/hyper.h
@@ -8,6 +8,7 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <stdbool.h>
 
 /*
  Return in iter functions to continue iterating.