Auto merge of #27302 - jdm:gst-package-mac, r=Manishearth

Make gstreamer packaging explicit

This change aligns Windows and macOS in terms of loading an explicit set of included plugins when initializing gstreamer. It also creates a single source of truth - the set of expected plugins is generated in a build script by the same python code that is used for packaging, so it should be impossible for platforms relying on this system to get out of sync.

Fixes #27293

components/servo/build.rs

@@ -2,6 +2,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use std::env;
+use std::fs;
+use std::path::Path;
+use std::process::Command;
+
 fn main() {
     let layout_2013 = std::env::var_os("CARGO_FEATURE_LAYOUT_2013").is_some();
     let layout_2020 = std::env::var_os("CARGO_FEATURE_LAYOUT_2020").is_some();
@@ -12,9 +17,48 @@ fn main() {
     if layout_2013 && layout_2020 {
         error("Must not enable both of the `layout-2013` or `layout-2020` features.")
     }
+
+    println!("cargo:rerun-if-changed=../../python/servo/gstreamer.py");
+
+    let output = Command::new(find_python())
+        .arg("../../python/servo/gstreamer.py")
+        .arg(std::env::var_os("TARGET").unwrap())
+        .output()
+        .unwrap();
+    if !output.status.success() {
+        eprintln!("{}", String::from_utf8_lossy(&output.stdout));
+        eprintln!("{}", String::from_utf8_lossy(&output.stderr));
+        std::process::exit(1)
+    }
+    let path = Path::new(&env::var_os("OUT_DIR").unwrap()).join("gstreamer_plugins.rs");
+    fs::write(path, output.stdout).unwrap();
 }
 
 fn error(message: &str) {
     print!("\n\n    Error: {}\n\n", message);
-    std::process::exit(1)
+    std::process::exit(1);
+}
+
+fn find_python() -> String {
+    env::var("PYTHON2").ok().unwrap_or_else(|| {
+        let candidates = if cfg!(windows) {
+            ["python2.7.exe", "python27.exe", "python.exe"]
+        } else {
+            ["python2.7", "python2", "python"]
+        };
+        for &name in &candidates {
+            if Command::new(name)
+                .arg("--version")
+                .output()
+                .ok()
+                .map_or(false, |out| out.status.success())
+            {
+                return name.to_owned();
+            }
+        }
+        panic!(
+            "Can't find python (tried {})! Try fixing PATH or setting the PYTHON2 env var",
+            candidates.join(", ")
+        )
+    })
 }

components/servo/lib.rs

@@ -134,10 +134,15 @@ pub use servo_url as url;
 
 #[cfg(feature = "media-gstreamer")]
 mod media_platform {
+    #[cfg(any(windows, target_os = "macos"))]
+    mod gstreamer_plugins {
+        include!(concat!(env!("OUT_DIR"), "/gstreamer_plugins.rs"));
+    }
+
     use super::ServoMedia;
     use servo_media_gstreamer::GStreamerBackend;
 
-    #[cfg(target_os = "windows")]
+    #[cfg(feature = "uwp")]
     fn set_gstreamer_log_handler() {
         use gstreamer::{debug_add_log_function, debug_remove_default_log_function, DebugLevel};
 
@@ -165,7 +170,7 @@ mod media_platform {
         });
     }
 
-    #[cfg(windows)]
+    #[cfg(any(windows, target_os = "macos"))]
     pub fn init() {
         // UWP apps have the working directory set appropriately. Win32 apps
         // do not and need some assistance finding the DLLs.
@@ -177,66 +182,24 @@ mod media_platform {
             plugin_dir
         };
 
-        let uwp_plugins = [
-            "gstapp.dll",
-            "gstaudioconvert.dll",
-            "gstaudiofx.dll",
-            "gstaudioparsers.dll",
-            "gstaudioresample.dll",
-            "gstautodetect.dll",
-            "gstcoreelements.dll",
-            "gstdeinterlace.dll",
-            "gstinterleave.dll",
-            "gstisomp4.dll",
-            "gstlibav.dll",
-            "gstplayback.dll",
-            "gstproxy.dll",
-            "gsttypefindfunctions.dll",
-            "gstvideoconvert.dll",
-            "gstvideofilter.dll",
-            "gstvideoparsersbad.dll",
-            "gstvideoscale.dll",
-            "gstvolume.dll",
-            "gstwasapi.dll",
-        ];
-
-        let non_uwp_plugins = [
-            "gstmatroska.dll",
-            "gstnice.dll",
-            "gstogg.dll",
-            "gstopengl.dll",
-            "gstopus.dll",
-            "gstrtp.dll",
-            "gsttheora.dll",
-            "gstvorbis.dll",
-            "gstvpx.dll",
-            "gstwebrtc.dll",
-        ];
-
-        let plugins: Vec<_> = if cfg!(feature = "uwp") {
-            uwp_plugins.to_vec()
-        } else {
-            uwp_plugins
-                .iter()
-                .map(|&s| s)
-                .chain(non_uwp_plugins.iter().map(|&s| s))
-                .collect()
-        };
-
-        let backend = match GStreamerBackend::init_with_plugins(plugin_dir, &plugins) {
+        let backend = match GStreamerBackend::init_with_plugins(
+            plugin_dir,
+            &gstreamer_plugins::GSTREAMER_PLUGINS,
+        ) {
             Ok(b) => b,
             Err(e) => {
-                error!("Error initializing GStreamer: {:?}", e);
-                panic!()
+                eprintln!("Error initializing GStreamer: {:?}", e);
+                std::process::exit(1);
             },
         };
         ServoMedia::init_with_backend(backend);
-        if cfg!(feature = "uwp") {
+        #[cfg(feature = "uwp")]
+        {
             set_gstreamer_log_handler();
         }
     }
 
-    #[cfg(not(windows))]
+    #[cfg(not(any(windows, target_os = "macos")))]
     pub fn init() {
         ServoMedia::init::<GStreamerBackend>();
     }