ci: add pull-request checks and tagged releases

.github/workflows/checker.yml

@@ -0,0 +1,20 @@
+name: Checker
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v7
+
+      - name: Build and test
+        run: ./test_runner.sh

.github/workflows/release.yml

@@ -0,0 +1,68 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    name: Build and test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out tagged source
+        uses: actions/checkout@v7
+
+      - name: Build and test
+        run: ./test_runner.sh
+
+  release:
+    name: Package and publish
+    needs: check
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Check out tagged source and history
+        uses: actions/checkout@v7
+        with:
+          fetch-depth: 0
+
+      - name: Validate release tag
+        env:
+          TAG: ${{ github.ref_name }}
+        run: |
+          if [[ ! "$TAG" =~ ^v[0-9]+\.[0-9]+(\.[0-9]+)?$ ]]; then
+            echo "Release tags must be vMAJOR.MINOR or vMAJOR.MINOR.PATCH." >&2
+            exit 1
+          fi
+
+      - name: Verify tag is on master
+        env:
+          TAG: ${{ github.ref_name }}
+        run: |
+          git fetch origin master:refs/remotes/origin/master
+          tag_commit="$(git rev-list -n 1 "$TAG")"
+          git merge-base --is-ancestor "$tag_commit" origin/master
+
+      - name: Package release assets
+        env:
+          TAG: ${{ github.ref_name }}
+        run: ./scripts/package-release.sh "$TAG" release-artifacts
+
+      - name: Publish GitHub release
+        env:
+          GH_TOKEN: ${{ github.token }}
+          TAG: ${{ github.ref_name }}
+        run: |
+          assets=(release-artifacts/*)
+          if gh release view "$TAG" >/dev/null 2>&1; then
+            gh release upload "$TAG" "${assets[@]}" --clobber
+          else
+            gh release create "$TAG" "${assets[@]}" --generate-notes --verify-tag
+          fi

README.md

@@ -2,6 +2,31 @@
 
 This repo is compatible with the [cpp-container](https://github.com/ChicoState/cpp-container) Docker container.
 
+## Development and releases
+
+Run the local build and test checker with:
+
+```
+./test_runner.sh
+```
+
+The Checker GitHub Actions workflow runs this command for pull requests and
+manual dispatches. Release tags run the same checker before publication.
+
+To publish a Linux release, first merge the intended commit into `master`, then
+push a version tag. The initial release tag is `v0.1`; later releases may use
+`vMAJOR.MINOR` or `vMAJOR.MINOR.PATCH` tags.
+
+```
+git tag -a v0.1 -m "Release v0.1"
+git push origin v0.1
+```
+
+The release workflow rejects tags whose commits are not reachable from
+`master`. It publishes a source ZIP containing only `bitmap.h`, `bitmap.cpp`,
+`LICENSE`, and `README.md`, plus Linux x86_64 static-library and example-binary
+assets.
+
 ## Getting Started
 
 1. Clone this repository onto your development environment

bitmap.cpp

@@ -233,16 +233,16 @@ void Bitmap::save(std::string filename)
 bool Bitmap::isImage()
 {
 	const int height = pixels.size();
-  bool valid = true;
+  bool valid = height > 0;
+  int width = 0;
 
-	if( height == 0 || pixels[0].size() == 0)
+	if( valid )
 	{
-		valid = false;
+		width = pixels[0].size();
+		valid = width > 0;
 	}
 
-	const int width = pixels[0].size();
-
-	for(int row=0; row < height; row++)
+	for(int row=0; valid && row < height; row++)
 	{
 		if( pixels[row].size() != width )
 		{

examples/bitmap_example.cpp

@@ -0,0 +1,14 @@
+#include <iostream>
+
+#include "../bitmap.h"
+
+int main()
+{
+  PixelMatrix pixels(1, std::vector<Pixel>(1, Pixel(0, 128, 255)));
+  Bitmap image;
+  image.fromPixelMatrix(pixels);
+
+  std::cout << "Created a " << image.toPixelMatrix().size()
+            << "x" << image.toPixelMatrix()[0].size() << " bitmap.\n";
+  return image.isImage() ? 0 : 1;
+}

scripts/package-release.sh

@@ -0,0 +1,51 @@
+#!/bin/bash
+
+set -euo pipefail
+
+if [ "$#" -ne 2 ]; then
+  echo "Usage: $0 <tag> <output-directory>" >&2
+  exit 64
+fi
+
+tag="$1"
+if [[ ! "$tag" =~ ^v[0-9]+\.[0-9]+(\.[0-9]+)?$ ]]; then
+  echo "Release tag must be vMAJOR.MINOR or vMAJOR.MINOR.PATCH." >&2
+  exit 64
+fi
+
+project_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+output_dir="$2"
+mkdir -p "$output_dir"
+output_dir="$(cd "$output_dir" && pwd)"
+build_dir="$(mktemp -d "${TMPDIR:-/tmp}/bitmap-release.XXXXXX")"
+trap 'rm -rf "$build_dir"' EXIT
+
+cxx="${CXX:-g++}"
+compile_flags=(-std=c++11 -O2)
+source_archive="$output_dir/bitmap-${tag}-source.zip"
+static_library="$output_dir/libbitmap-${tag}-linux-x86_64.a"
+example_binary="$output_dir/bitmap-example-${tag}-linux-x86_64"
+
+rm -f "$source_archive" "$static_library" "$example_binary"
+
+(
+  cd "$project_root"
+  zip -q -j "$source_archive" bitmap.h bitmap.cpp LICENSE README.md
+)
+
+expected_archive_contents=$'LICENSE\nREADME.md\nbitmap.cpp\nbitmap.h'
+actual_archive_contents="$(zipinfo -1 "$source_archive" | LC_ALL=C sort)"
+if [ "$actual_archive_contents" != "$expected_archive_contents" ]; then
+  echo "Source archive contains unexpected files." >&2
+  exit 1
+fi
+
+"$cxx" "${compile_flags[@]}" -c "$project_root/bitmap.cpp" -o "$build_dir/bitmap.o"
+ar rcs "$static_library" "$build_dir/bitmap.o"
+"$cxx" "${compile_flags[@]}" "$project_root/examples/bitmap_example.cpp" \
+  "$static_library" -o "$example_binary"
+"$example_binary"
+
+test -s "$source_archive"
+test -s "$static_library"
+test -x "$example_binary"

test_runner.sh

@@ -1,3 +1,17 @@
 #!/bin/bash
 
-g++ -c bitmap.cpp -o bitmap.o
+set -euo pipefail
+
+project_root="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+build_dir="$(mktemp -d "${TMPDIR:-/tmp}/bitmap-tests.XXXXXX")"
+trap 'rm -rf "$build_dir"' EXIT
+
+cxx="${CXX:-g++}"
+compile_flags=(-std=c++11 -Wall -Wextra -Wpedantic)
+
+"$cxx" "${compile_flags[@]}" -c "$project_root/bitmap.cpp" -o "$build_dir/bitmap.o"
+"$cxx" "${compile_flags[@]}" "$project_root/tests/bitmap_test.cpp" \
+  "$project_root/bitmap.cpp" -o "$build_dir/bitmap_test"
+"$build_dir/bitmap_test"
+"$cxx" "${compile_flags[@]}" "$project_root/examples/bitmap_example.cpp" \
+  "$project_root/bitmap.cpp" -o "$build_dir/bitmap_example"

tests/bitmap_test.cpp

@@ -0,0 +1,33 @@
+#include <cassert>
+#include <iostream>
+
+#include "../bitmap.h"
+
+int main()
+{
+  Pixel purple(128, 0, 255);
+  assert(purple.red == 128);
+  assert(purple.green == 0);
+  assert(purple.blue == 255);
+
+  Bitmap image;
+  assert(!image.isImage());
+
+  PixelMatrix pixels(2, std::vector<Pixel>(3, Pixel(1, 2, 3)));
+  image.fromPixelMatrix(pixels);
+  assert(image.isImage());
+  assert(image.toPixelMatrix().size() == 2);
+  assert(image.toPixelMatrix()[0].size() == 3);
+
+  pixels[1].push_back(Pixel());
+  image.fromPixelMatrix(pixels);
+  assert(!image.isImage());
+
+  pixels.resize(1);
+  pixels[0][0] = Pixel(256, 0, 0);
+  image.fromPixelMatrix(pixels);
+  assert(!image.isImage());
+
+  std::cout << "Bitmap tests passed\n";
+  return 0;
+}