Implement `bootstrap-gstreamer` for all platforms

This change makes it so that the Platform classes can now handle
installing GStreamer dependencies and properly setting up the
environment including when cross-compiling. For Windows and Linux
is now installed into `target/dependencies/gstreamer` when not installed
system-wide. In addition:

1. Creating and moving existing environment path append helpers to
   `util.py`.
2. Combining the `set_run_env` and `build_dev` functions and moving
   some outside code into them so that it can be shared. Now code that
   used to call `set_run_env` calls `build_dev` and then
   `os.environ.update(...)`.
3. Adding Python typing information in many places.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

1 files changed, 87 insertions, 10 deletions

diff --git a/python/servo/platform/windows.py b/python/servo/platform/windows.py
index cea8de5a5dd..8ea2a0a5650 100644
--- a/python/servo/platform/windows.py
+++ b/python/servo/platform/windows.py
@@ -10,14 +10,15 @@
 import os
 import shutil
 import subprocess
+import tempfile
+from typing import Optional
 import urllib
 import zipfile
-
 from distutils.version import LooseVersion
 
 import six
+from .. import util
 from .base import Base
-from ..util import extract, download_file
 
 DEPS_URL = "https://github.com/servo/servo-build-deps/releases/download/msvc-deps/"
 DEPENDENCIES = {
@@ -31,10 +32,22 @@ DEPENDENCIES = {
     "openxr-loader-uwp": "1.0",
 }
 
+URL_BASE = "https://gstreamer.freedesktop.org/data/pkg/windows/1.16.0/"
+GSTREAMER_URL = f"{URL_BASE}/gstreamer-1.0-msvc-x86_64-1.16.0.msi"
+GSTREAMER_DEVEL_URL = f"{URL_BASE}/gstreamer-1.0-devel-msvc-x86_64-1.16.0.msi"
+DEPENDENCIES_DIR = os.path.join(util.get_target_dir(), "dependencies")
+
 
 class Windows(Base):
-    def __init__(self):
-        pass
+    def __init__(self, triple: str):
+        super().__init__(triple)
+        self.is_windows = True
+
+    def executable_suffix(self):
+        return ".exe"
+
+    def library_path_variable_name(self):
+        return "LIB"
 
     @staticmethod
     def cmake_already_installed(required_version: str) -> bool:
@@ -51,11 +64,11 @@ class Windows(Base):
     def prepare_file(cls, deps_dir: str, zip_path: str, full_spec: str):
         if not os.path.isfile(zip_path):
             zip_url = "{}{}.zip".format(DEPS_URL, urllib.parse.quote(full_spec))
-            download_file(full_spec, zip_url, zip_path)
+            util.download_file(full_spec, zip_url, zip_path)
 
-        print("Extracting {}...".format(full_spec), end='')
+        print("Extracting {}...".format(full_spec), end="")
         try:
-            extract(zip_path, deps_dir)
+            util.extract(zip_path, deps_dir)
         except zipfile.BadZipfile:
             print("\nError: %s.zip is not a valid zip file, redownload..." % full_spec)
             os.remove(zip_path)
@@ -70,7 +83,7 @@ class Windows(Base):
             return os.path.join(deps_dir, package, version)
 
         to_install = {}
-        for (package, version) in DEPENDENCIES.items():
+        for package, version in DEPENDENCIES.items():
             # Don't install CMake if it already exists in PATH
             if package == "cmake" and self.cmake_already_installed(version):
                 continue
@@ -82,8 +95,8 @@ class Windows(Base):
             return False
 
         print("Installing missing MSVC dependencies...")
-        for (package, version) in to_install.items():
-            full_spec = '{}-{}'.format(package, version)
+        for package, version in to_install.items():
+            full_spec = "{}-{}".format(package, version)
 
             package_dir = get_package_dir(package, version)
             parent_dir = os.path.dirname(package_dir)
@@ -96,3 +109,67 @@ class Windows(Base):
             os.rename(extracted_path, package_dir)
 
         return True
+
+    def gstreamer_root(self, cross_compilation_target: Optional[str]) -> Optional[str]:
+        build_target_triple = cross_compilation_target or self.triple
+        gst_arch_names = {
+            "x86_64": "X86_64",
+            "x86": "X86",
+            "aarch64": "ARM64",
+        }
+        gst_arch_name = gst_arch_names[build_target_triple.split("-")[0]]
+
+        # The bootstraped version of GStreamer always takes precedance of the installed vesion.
+        prepackaged_root = os.path.join(
+            DEPENDENCIES_DIR, "gstreamer", "1.0", gst_arch_name
+        )
+        if os.path.exists(os.path.join(prepackaged_root, "bin", "ffi-7.dll")):
+            return prepackaged_root
+
+        # The installed version of GStreamer often sets an environment variable pointing to
+        # the install location.
+        root_from_env = os.environ.get(f"GSTREAMER_1_0_ROOT_{gst_arch_name}")
+        if root_from_env:
+            return root_from_env
+
+        # If all else fails, look for an installation in the default install directory.
+        default_root = os.path.join("C:\\gstreamer\\1.0", gst_arch_name)
+        if os.path.exists(os.path.join(default_root, "bin", "ffi-7.dll")):
+            return default_root
+
+        return None
+
+    def is_gstreamer_installed(self, cross_compilation_target: Optional[str]) -> bool:
+        return self.gstreamer_root(cross_compilation_target) is not None
+
+    def _platform_bootstrap_gstreamer(self, force: bool) -> bool:
+        if not force and self.is_gstreamer_installed(cross_compilation_target=None):
+            return False
+
+        if "x86_64" not in self.triple:
+            print("Bootstrapping gstreamer not supported on "
+                  "non-x86-64 Windows. Please install manually")
+            return False
+
+        with tempfile.TemporaryDirectory() as temp_dir:
+            libs_msi = os.path.join(temp_dir, GSTREAMER_URL.rsplit("/", maxsplit=1)[-1])
+            devel_msi = os.path.join(
+                temp_dir, GSTREAMER_DEVEL_URL.rsplit("/", maxsplit=1)[-1]
+            )
+
+            util.download_file("GStreamer libraries", GSTREAMER_URL, libs_msi)
+            util.download_file(
+                "GStreamer development support", GSTREAMER_DEVEL_URL, devel_msi
+            )
+
+            print(f"Installing GStreamer packages to {DEPENDENCIES_DIR}...")
+            os.makedirs(DEPENDENCIES_DIR, exist_ok=True)
+            common_args = [
+                f"TARGETDIR={DEPENDENCIES_DIR}",  # Install destination
+                "/qn",  # Quiet mode
+            ]
+            subprocess.check_call(["msiexec", "/a", libs_msi] + common_args)
+            subprocess.check_call(["msiexec", "/a", devel_msi] + common_args)
+
+            assert self.is_gstreamer_installed(cross_compilation_target=None)
+            return True