chore(ffi): revamp gen_header using cargo-expand

.github/workflows/CI.yml

@@ -213,6 +213,13 @@ jobs:
         with:
           tool: cbindgen
 
+      - name: Install cargo-expand
+        uses: taiki-e/cache-cargo-install-action@v1
+        with:
+          tool: cargo-expand
+
+      - uses: Swatinem/rust-cache@v2
+
       - name: Build FFI
         run: cargo build --features client,http1,http2,ffi
         env:

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