C library: add script to download header files and update binding #12

Author: greenrobot-team

dev-doc/updating-c-library.md

@@ -5,8 +5,9 @@ Dart won't error on C function signature mismatch, leading to obscure memory bug
 
 ## C libraries
 
-For Dart Native and unit tests and for Flutter (`flutter_libs` and `sync_flutter_libs` plugins) 
-on Linux and Windows:  
+For Dart Native and unit tests ([install.sh](../install.sh)),
+for the binding update script (see below) and
+for Flutter (`flutter_libs` and `sync_flutter_libs` plugins) on Linux and Windows:  
 ```
 ./tool/set-c-version.sh 0.20.0
 ```
@@ -24,18 +25,18 @@ For the Flutter plugins on iOS/macOS ([view releases](https://github.com/objectb
 For each, add an entry (see previous releases) to the [CHANGELOG](../objectbox/CHANGELOG.md).
 
 ## Dart C API bindings
-Download source code of an [objectbox-c release version](https://github.com/objectbox/objectbox-c/releases).
-- Update [objectbox.h](../objectbox/lib/src/native/bindings/objectbox.h)
-- Update [objectbox-dart.h](../objectbox/lib/src/native/bindings/objectbox-dart.h)
-- Update [objectbox-sync.h](../objectbox/lib/src/native/bindings/objectbox-sync.h)
-- Replace `const void*` by `const uint8_t*` in all objectbox*.h files 
-  (see ffigen note in [pubspec.yaml](../objectbox/pubspec.yaml)).
-- Execute `dart run ffigen` in the `objectbox` directory. This requires LLVM libraries 
-  (see [ffigen docs](https://pub.dev/packages/ffigen#installing-llvm) 
-  and the ffigen section in [pubspec.yaml](../objectbox/pubspec.yaml)).
-- Copy/update enums that need to be exposed to users from [objectbox_c.dart](../objectbox/lib/src/native/bindings/objectbox_c.dart) 
+To download the C library header files and generate bindings with ffigen (requires LLVM libraries,
+see [ffigen docs](https://pub.dev/packages/ffigen#installing-llvm)
+and the ffigen section in [pubspec.yaml](../objectbox/pubspec.yaml)):
+```
+./tool/update-c-binding.sh
+```
+
+Then manually:
+- Copy/update enums that need to be exposed to users
+  from [objectbox_c.dart](../objectbox/lib/src/native/bindings/objectbox_c.dart) 
   to [enums.dart](../objectbox/lib/src/modelinfo/enums.dart).
-- Have a look at the changed files to see if some call sites need to be updated.
+- Check the changed files, make any required changes in the Dart library (like method signature changes).
 - ⚠️ Update minimum C library and core version and notes as needed in [bindings.dart](../objectbox/lib/src/native/bindings/bindings.dart).
 
   Note: the embedded C library and core version can be looked up

tool/set-c-version.sh

@@ -2,7 +2,8 @@
 . "$(dirname "$0")"/common.sh
 
 # Changes the C library version used in
-# - the install script (for Dart Native and unit tests) and
+# - the install script (for Dart Native and unit tests),
+# - the binding update script and
 # - both Flutter plugins (for Flutter on Linux, Windows).
 
 if [[ "$#" -ne "1" ]]; then
@@ -17,6 +18,7 @@ echo "Setting cLibVersion and OBJECTBOX_VERSION version: $version"
 
 versionExpr="s/cLibVersion=[0-9]\+\.[0-9]\+\.[0-9]\+/cLibVersion=${version}/g"
 update install.sh "${versionExpr}"
+update tool/update-c-binding.sh "${versionExpr}"
 
 versionExpr="s/OBJECTBOX_VERSION [0-9]\+\.[0-9]\+\.[0-9]\+/OBJECTBOX_VERSION ${version}/g"
 update flutter_libs/linux/CMakeLists.txt "${versionExpr}"

tool/update-c-binding.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+. "$(dirname "$0")"/common.sh
+
+# Downloads the C library source files of a specific release from GitHub,
+# copies the header files, makes some required modifications
+# and runs the ffigen binding generator on them.
+
+cLibVersion=0.20.0
+echo "Downloading C library source files from GitHub..."
+
+# Note: the release archives do not contain objectbox-dart.h, so get the full sources.
+archiveExt="zip"
+downloadUrl="https://github.com/objectbox/objectbox-c/archive/refs/tags/v${cLibVersion}.${archiveExt}"
+echo "Download URL: ${downloadUrl}"
+
+targetDir="objectbox/download"
+archiveFile="${targetDir}/objectbox-c-${cLibVersion}.${archiveExt}"
+mkdir -p "$(dirname "${archiveFile}")"
+
+# Support both curl and wget because their availability is platform dependent
+if [ -x "$(command -v curl)" ]; then
+    curl --location --fail --output "${archiveFile}" "${downloadUrl}"
+else
+    wget --no-verbose --output-document="${archiveFile}" "${downloadUrl}"
+fi
+
+if [[ ! -s ${archiveFile} ]]; then
+    echo "Error: download failed (file ${archiveFile} does not exist or is empty)"
+    exit 1
+fi
+
+echo
+echo "Downloaded:"
+du -h "${archiveFile}"
+
+echo
+echo "Extracting into ${targetDir}..."
+unzip "${archiveFile}" -d "${targetDir}"
+
+headerBuildDir="objectbox/lib/src/native/bindings"
+echo
+echo "Copying to ${headerBuildDir}..."
+mkdir -p "${headerBuildDir}"
+cp "${targetDir}/objectbox-c-${cLibVersion}"/include/*.h "${headerBuildDir}"
+ls -l "${headerBuildDir}"
+
+# Replace `const void*` by `const uint8_t*` in all objectbox*.h files
+# (see ffigen note in ../objectbox/pubspec.yaml).
+echo
+echo "Replacing 'const void*' by 'const uint8_t*'..."
+replaceVoidExpr="s/const void\*/const uint8_t*/g"
+update objectbox/lib/src/native/bindings/objectbox.h "${replaceVoidExpr}"
+update objectbox/lib/src/native/bindings/objectbox-dart.h "${replaceVoidExpr}"
+update objectbox/lib/src/native/bindings/objectbox-sync.h "${replaceVoidExpr}"
+
+# This requires LLVM libraries
+# (see ffigen docs https://pub.dev/packages/ffigen#installing-llvm
+# and the ffigen section in ../objectbox/pubspec.yaml).
+echo
+echo "Generating bindings with ffigen (requires LLVM libraries)..."
+cd objectbox
+dart run ffigen