meson: Define gst_plugins with list of dependencies

This is needed to link gst-full with Rust plugins. The script requires
either python11 or the tomli module.

.gitlab-ci.yml

@@ -43,7 +43,7 @@ stages:
 .debian:11-stable:
   extends: .debian:11
   variables:
-    FDO_DISTRIBUTION_TAG: '$GST_RS_STABLE-${GST_RS_IMG_TAG}_2022-07-19.0'
+    FDO_DISTRIBUTION_TAG: '$GST_RS_STABLE-${GST_RS_IMG_TAG}_2022-08-31.1'
     FDO_BASE_IMAGE: "registry.freedesktop.org/gstreamer/gstreamer-rs/debian/bullseye-slim:$GST_RS_STABLE-$GST_RS_IMG_TAG"
 
 .debian:11-msrv:
@@ -63,11 +63,12 @@ stages:
   - .fdo.container-build@debian
   stage: prep
   variables:
-    FDO_DISTRIBUTION_PACKAGES: "libcsound64-dev llvm clang nasm libsodium-dev"
+    FDO_DISTRIBUTION_PACKAGES: "libcsound64-dev llvm clang nasm libsodium-dev libwebp-dev python3-pip"
     FDO_DISTRIBUTION_EXEC: >-
       bash ci/install-dav1d.sh &&
       apt clean &&
-      bash ./ci/install-rust-ext.sh
+      bash ./ci/install-rust-ext.sh &&
+      pip install tomli
   rules:
     - if: '$UPDATE_IMG == null'
 
@@ -216,6 +217,22 @@ gst-build:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"
       when: 'manual'
       allow_failure: true
+  variables:
+    MESON_ARGS: >
+      -Domx=disabled
+      -Dpython=disabled
+      -Dlibav=disabled
+      -Dlibnice=disabled
+      -Dugly=disabled
+      -Dbad=disabled
+      -Ddevtools=disabled
+      -Dges=disabled
+      -Drtsp_server=disabled
+      -Dvaapi=disabled
+      -Dsharp=disabled
+      -Dgst-examples=disabled
+      -Drs=enabled
+      -Dgst-plugins-rs:sodium=system
   script:
     - P=$(pwd)
     - cd ..
@@ -223,13 +240,18 @@ gst-build:
     - git clone --depth 1 https://gitlab.freedesktop.org/gstreamer/gstreamer.git --branch main
     - cd gstreamer
     - ln -s $P subprojects/gst-plugins-rs
-    - meson build -Domx=disabled -Dpython=disabled -Dlibav=disabled -Dlibnice=disabled -Dugly=disabled -Dbad=disabled -Ddevtools=disabled -Dges=disabled -Drtsp_server=disabled -Dvaapi=disabled -Dsharp=disabled -Dgst-examples=disabled -Drs=enabled -Dgst-plugins-rs:sodium=system
+    - meson build $MESON_ARGS
     - ninja -C build
+    # Check static Rust plugins can be linked into gst-full
+    - meson build-gst-full --default-library=static $MESON_ARGS
+    - ninja -C build-gst-full
+    - meson devenv -C build-gst-full gst-inspect-1.0 rsaudiofx
   artifacts:
     expire_in: '7 days'
     when: always
     paths:
       - 'build/meson-logs/'
+      - 'build-gst-full/meson-logs/'
 
 rustfmt:
   extends: .img-stable

dependencies.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+
+# Parse Cargo.toml files for each plugin to collect their external dependencies.
+# Meson will lookup those dependencies using pkg-config to be able to link
+# static Rust plugins into gst-full.
+
+from argparse import ArgumentParser
+from pathlib import Path
+
+try:
+    # Python11 stdlib
+    import tomllib
+except ImportError:
+    import tomli as tomllib
+
+
+PARSER = ArgumentParser()
+PARSER.add_argument('src_dir', type=Path)
+PARSER.add_argument('plugins', nargs='*')
+
+
+# Map plugin name to directory name, for those that does not match.
+RENAMES = {
+    'rsaudiofx': 'audiofx',
+    'rsfile': 'file',
+    'rsflv': 'flavors',
+    'rstextwrap': 'wrap',
+    'rsjson': 'json',
+    'rsregex': 'regex',
+    'rswebp': 'webp',
+    'textahead': 'ahead',
+    'rsonvif': 'onvif',
+    'rstracers': 'tracers',
+    'rsclosedcaption': 'closedcaption',
+    'rsdav1d': 'dav1d',
+}
+
+
+if __name__ == "__main__":
+    opts = PARSER.parse_args()
+
+    deps = set()
+    for p in opts.plugins:
+        assert p.startswith('gst')
+        name = p[3:]
+        name = RENAMES.get(name, name)
+        files = list(opts.src_dir.glob(f'**/{name}/Cargo.toml'))
+        assert len(files) == 1
+        with files[0].open('rb') as f:
+            data = tomllib.load(f)
+            try:
+                requires = data['package']['metadata']['capi']['pkg_config']['requires_private']
+            except KeyError:
+                continue
+            deps.update([i.strip() for i in requires.split(',')])
+    print(','.join(deps))

meson.build

@@ -5,6 +5,7 @@ project('gst-plugins-rs',
         meson_version : '>= 0.60')
 
 python = import('python').find_installation()
+fs = import('fs')
 
 if get_option('debug')
   target = 'debug'
@@ -137,12 +138,6 @@ if static_build or get_option('default_library') == 'both'
   endforeach
 endif
 
-pc_files = []
-foreach p, lib : plugins
-  # skip the 'lib' prefix in plugin name
-  pc_files += [lib.substring(3) + '.pc']
-endforeach
-
 # Need to depends on all gstreamer-rs deps to ensure they are built
 # before gstreamer-rs when building with gst-build.
 # Custom targets can't depend on dependency() objects so we have to depend
@@ -164,10 +159,14 @@ deps = [
   ['gstreamer-webrtc-1.0', 'gst-plugins-bad', 'gstwebrtc_dep', 'gstwebrtc_dep'],
 ]
 
+# Used to not lookup the same dependency multiple times which clutters logs
+deps_cache = {}
+
 foreach d: deps
   dep = dependency(d[0], version : gst_req,
     fallback : [d[1], d[2]])
   set_variable(d[2], dep)
+  deps_cache += {d[0]: dep}
   if dep.type_name() == 'internal'
     lib = subproject(d[1]).get_variable(d[3])
     depends += lib
@@ -216,6 +215,38 @@ rs_plugins = custom_target('gst-plugins-rs',
 
 plugins = rs_plugins.to_list()
 
+# This is used by GStreamer to static link Rust plugins into gst-full
+gst_plugins = []
+pc_files = []
+foreach plugin : plugins
+  # skip the 'lib' prefix and extension from plugin path
+  plugin_name = fs.stem(plugin.full_path()).substring(3)
+
+  # Extract plugin dependencies from their Cargo.toml file
+  plugin_deps = []
+  p = run_command('dependencies.py', meson.current_source_dir(), plugin_name,
+    capture: true,
+    check: true)
+  foreach dep_name : p.stdout().strip().split(',')
+    if deps_cache.has_key(dep_name)
+      plugin_deps += deps_cache[dep_name]
+    else
+      dep = dependency(dep_name, required: false)
+      plugin_deps += dep
+      deps_cache += {dep_name: dep}
+    endif
+  endforeach
+
+  dep = declare_dependency(
+    link_with: plugin,
+    dependencies: plugin_deps,
+    variables: {'full_path': plugin.full_path()},
+  )
+  meson.override_dependency(plugin_name, dep)
+  gst_plugins += dep
+  pc_files += [plugin_name + '.pc']
+endforeach
+
 subdir('docs')
 
 # We don't need to pass a command as we depends on the target above