Generate AppImage on GitHub Actions

Fixes #695. Supersedes #172. See https://appimage.org/.

linux/create_appimage.sh

@@ -0,0 +1,113 @@
+#!/usr/bin/env bash
+
+((${BASH_VERSION%%.*} >= 4)) || { echo >&2 "$0: Error: Please upgrade Bash."; exit 1; }
+
+set -euxo pipefail
+
+readonly appdir="$1" # input path (Audacity install directory)
+readonly appimage="$2" # output path to use for created AppImage
+
+#============================================================================
+# Helper functions
+#============================================================================
+
+function download_github_release()
+{
+    local -r repo_slug="$1" release_tag="$2" file="$3"
+    wget -q --show-progress "https://github.com/${repo_slug}/releases/download/${release_tag}/${file}"
+    chmod +x "${file}"
+}
+
+function extract_appimage()
+{
+    # Extract AppImage so we can run it without having to install FUSE
+    local -r image="$1" binary_name="$2"
+    local -r dir="${image%.AppImage}.AppDir"
+    "./${image}" --appimage-extract >/dev/null # dest folder "squashfs-root"
+    mv squashfs-root "${dir}" # rename folder to avoid collisions
+    ln -s "${dir}/AppRun" "${binary_name}" # symlink for convenience
+    rm -f "${image}"
+}
+
+function download_appimage_release()
+{
+    local -r github_repo_slug="$1" binary_name="$2" tag="$3"
+    local -r image="${binary_name}-x86_64.AppImage"
+    download_github_release "${github_repo_slug}" "${tag}" "${image}"
+    extract_appimage "${image}" "${binary_name}"
+}
+
+function download_linuxdeploy_component()
+{
+    local -r component="$1" tag="$2"
+    download_appimage_release "linuxdeploy/$1" "$1" "$2"
+}
+
+function create_path()
+{
+    local -r path="$1"
+    if [[ -d "${path}" ]]; then
+        return 1 # already exists
+    fi
+    mkdir -p "${path}"
+}
+
+#============================================================================
+# Fetch AppImage packaging tools
+#============================================================================
+
+if create_path "appimagetool"; then
+(
+    cd "appimagetool"
+    download_appimage_release AppImage/AppImageKit appimagetool continuous
+)
+fi
+export PATH="${PWD%/}/appimagetool:${PATH}"
+appimagetool --version
+
+if create_path "linuxdeploy"; then
+(
+    cd "linuxdeploy"
+    download_linuxdeploy_component linuxdeploy continuous
+)
+fi
+export PATH="${PWD%/}/linuxdeploy:${PATH}"
+linuxdeploy --list-plugins
+
+#============================================================================
+# Create symlinks
+#============================================================================
+
+ln -sf --no-dereference . "${appdir}/usr"
+ln -sf share/applications/audacity.desktop "${appdir}/audacity.desktop"
+ln -sf share/icons/hicolor/scalable/apps/audacity.svg "${appdir}/audacity.svg"
+ln -sf share/icons/hicolor/scalable/apps/audacity.svg "${appdir}/.DirIcon"
+
+#============================================================================
+# Bundle dependencies
+#============================================================================
+
+# HACK: Some wxWidget libraries depend on themselves. Add
+# them to LD_LIBRARY_PATH so that linuxdeploy can find them.
+export LD_LIBRARY_PATH="${appdir}/usr/lib/audacity:${LD_LIBRARY_PATH-}"
+
+linuxdeploy --appdir "${appdir}" # add all shared library dependencies
+
+#============================================================================
+# Build AppImage
+#============================================================================
+
+appimagetool_args=(
+    # none
+)
+
+if [[ "${AUDACITY_UPDATE_INFO-}" ]]; then
+    # Enable updates. See https://github.com/AppImage/AppImageSpec/blob/master/draft.md#update-information
+    appimagetool_args+=( --updateinformation="${AUDACITY_UPDATE_INFO}" )
+else
+    echo >&2 "$0: Automatic updates disabled"
+fi
+
+# Create AppImage
+cd "$(dirname "${appimage}")" # otherwise zsync created in wrong directory
+appimagetool "${appimagetool_args[@]}" "${appdir}" "${appimage}"