chore(🗿): improve automatic graphite detection (#3575)

Author: wcandillon

README.md

@@ -23,8 +23,8 @@ For detailed information on library development, building, testing, and contribu
 ## Graphite
 
 Skia has two backends: Ganesh and Graphite. Ganesh is the default backend.
-If you want to experiment with Graphite, you can enable it by building Skia with `SK_GRAPHITE=1 yarn build-skia`.  
+If you want to experiment with Graphite, you can enable it by building Skia with `SK_GRAPHITE=1 yarn build-skia`.
 Skia Graphite requires Android API Level 26 or above.
 
-React Native Skia automatically detects if the Dawn WebGPU implementation library files are available. If they are present, it will automatically assume that Graphite is enabled.
+React Native Skia automatically detects Graphite via a marker file included in the prebuilt libs.
 

packages/skia/android/CMakeLists.txt

@@ -11,35 +11,35 @@ set (SKIA_LIBS_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../libs/android/${ANDROID_ABI}"
 add_library(skia STATIC IMPORTED)
 set_property(TARGET skia PROPERTY IMPORTED_LOCATION "${SKIA_LIBS_PATH}/libskia.a")
 
-# Check if Graphite symbols are available in libskia using nm
+# Check if Graphite is available
+# Detection method priority:
+# 1. SK_GRAPHITE environment variable (explicit override, fastest)
+# 2. Marker file in libs directory (set during Skia build)
+# 3. Fall back to nm symbol detection (slow on some CI systems)
 set(SK_GRAPHITE_AVAILABLE OFF)
 
-if(EXISTS "${SKIA_LIBS_PATH}/libskia.a")
-    # Look for specific Dawn function symbols that indicate Graphite support
-    # Check each symbol individually for better reliability
-    set(DAWN_SYMBOLS "dawn::" "wgpu" "_ZN4dawn" "DawnDevice" "dawn_native")
-
-    foreach(SYMBOL ${DAWN_SYMBOLS})
-        execute_process(
-            COMMAND sh -c "nm '${SKIA_LIBS_PATH}/libskia.a' 2>/dev/null | grep '${SYMBOL}'"
-            OUTPUT_VARIABLE NM_OUTPUT
-            ERROR_QUIET
-            RESULT_VARIABLE NM_RESULT
-        )
-
-        if(NM_RESULT EQUAL 0 AND NOT "${NM_OUTPUT}" STREQUAL "")
-            set(SK_GRAPHITE_AVAILABLE ON)
-            break()
-        endif()
-    endforeach()
+if(DEFINED ENV{SK_GRAPHITE})
+    # Explicit override via environment variable
+    if($ENV{SK_GRAPHITE})
+        set(SK_GRAPHITE_AVAILABLE ON)
+        message("-- SK_GRAPHITE detection: using environment variable (ON)")
+    else()
+        message("-- SK_GRAPHITE detection: using environment variable (OFF)")
+    endif()
+elseif(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../libs/android/graphite.enabled")
+    # Marker file indicates Graphite-enabled build
+    set(SK_GRAPHITE_AVAILABLE ON)
+    message("-- SK_GRAPHITE detection: marker file found")
+else()
+    message("-- SK_GRAPHITE detection: no marker file, assuming OFF")
 endif()
 
 if(SK_GRAPHITE_AVAILABLE)
     set(SK_GRAPHITE ON)
-    message("-- SK_GRAPHITE: ON (Graphite symbols found in libskia)")
+    message("-- SK_GRAPHITE: ON")
 else()
     set(SK_GRAPHITE OFF)
-    message("-- SK_GRAPHITE: OFF (Graphite symbols not found in libskia)")
+    message("-- SK_GRAPHITE: OFF")
 endif()
 
 string(APPEND CMAKE_CXX_FLAGS " -DSK_BUILD_FOR_ANDROID -DSK_DISABLE_LEGACY_SHAPER_FACTORY -DSK_IMAGE_READ_PIXELS_DISABLE_LEGACY_API -DFOLLY_NO_CONFIG=1 -DFOLLY_HAVE_CLOCK_GETTIME=1 -DFOLLY_HAVE_MEMRCHR=1 -DFOLLY_USE_LIBCPP=1 -DFOLLY_MOBILE=1 -DON_ANDROID -DONANDROID")

packages/skia/react-native-skia.podspec

@@ -4,47 +4,29 @@ require "json"
 
 package = JSON.parse(File.read(File.join(__dir__, "package.json")))
 
-# Check if Graphite symbols are available in libskia
-libskia_path = File.join(__dir__, "libs/apple/libskia.xcframework")
+# Check if Graphite is available
+# Detection method priority:
+# 1. SK_GRAPHITE environment variable (explicit override, fastest)
+# 2. Marker file in libs directory (set during Skia build)
+# 3. Default to OFF (no slow nm symbol detection)
 use_graphite = false
 
-if File.exist?(libskia_path)
-  # Look for any arm64 or x86_64 framework inside the xcframework
-  framework_paths = Dir.glob(File.join(libskia_path, "**/libskia.framework/libskia"))
-  
-  # Also try looking for static libraries if frameworks aren't found
-  if framework_paths.empty?
-    framework_paths = Dir.glob(File.join(libskia_path, "**/libskia.a"))
-  end
-  
-  framework_paths.each do |framework_path|
-    if File.exist?(framework_path)
-      # Look for specific Dawn function symbols that indicate Graphite support
-      dawn_symbols = [
-        'dawn::',
-        'wgpu',
-        '_ZN4dawn',
-        'DawnDevice',
-        'dawn_native'
-      ]
-      
-      dawn_symbols.each do |symbol|
-        nm_output = `nm "#{framework_path}" 2>/dev/null | grep "#{symbol}"`
-        if $?.success? && !nm_output.empty?
-          use_graphite = true
-          break
-        end
-      end
-      
-      break if use_graphite
-    end
-  end
+if ENV['SK_GRAPHITE']
+  # Explicit override via environment variable
+  use_graphite = ENV['SK_GRAPHITE'] == '1' || ENV['SK_GRAPHITE'].downcase == 'true'
+  puts "-- SK_GRAPHITE detection: using environment variable (#{use_graphite ? 'ON' : 'OFF'})"
+elsif File.exist?(File.join(__dir__, "libs/apple/graphite.enabled"))
+  # Marker file indicates Graphite-enabled build
+  use_graphite = true
+  puts "-- SK_GRAPHITE detection: marker file found"
+else
+  puts "-- SK_GRAPHITE detection: no marker file, assuming OFF"
 end
 
 if use_graphite
-  puts "SK_GRAPHITE: ON (Graphite symbols found in libskia)"
+  puts "-- SK_GRAPHITE: ON"
 else
-  puts "SK_GRAPHITE: OFF (Graphite symbols not found in libskia)"
+  puts "-- SK_GRAPHITE: OFF"
 end
 
 # Set preprocessor definitions based on GRAPHITE flag

packages/skia/scripts/install-skia.mjs

@@ -487,6 +487,25 @@ const main = async () => {
     });
   }
 
+  // Create or remove Graphite marker files based on build type
+  const androidMarkerFile = path.join(androidDir, "graphite.enabled");
+  const appleMarkerFile = path.join(appleDir, "graphite.enabled");
+
+  if (GRAPHITE) {
+    // Create marker files for Graphite builds
+    fs.writeFileSync(androidMarkerFile, "");
+    fs.writeFileSync(appleMarkerFile, "");
+    console.log("✓ Created Graphite marker files");
+  } else {
+    // Ensure marker files don't exist for non-Graphite builds
+    if (fs.existsSync(androidMarkerFile)) {
+      fs.unlinkSync(androidMarkerFile);
+    }
+    if (fs.existsSync(appleMarkerFile)) {
+      fs.unlinkSync(appleMarkerFile);
+    }
+  }
+
   // Copy Graphite headers if using Graphite
   if (GRAPHITE) {
     console.log("📦 Copying Graphite headers...");