Optionally override codegen script defaults via envvars

Summary:
The codegen helper script, `generate-specs.sh`, is being used to generate code for the FBReactNativeSpec and React-Fabric/rncore pods. The script now supports overriding several defaults by setting the following environment variables:

- SRCS_DIR: Path to JavaScript sources, defaults to $RN_DIR/Libraries/
- LIBRARY_NAME: Defaults to FBReactNativeSpec
- MODULES_OUTPUT_DIR: Defaults to Libraries/$LIBRARY_NAME/$LIBRARY_NAME
- COMPONENTS_LIBRARY_NAME: Defaults to rncore
- COMPONENTS_OUTPUT_DIR: Defaults to ReactCommon/react/renderer/components/$COMPONENTS_LIBRARY_NAME

The CocoaPods codegen integration has been updated to take advantage of these.

**Example CocoaPods usage:**

```
# packages/rn-tester/NativeModuleExample/RNTesterSpecs.podspec
Pod::Spec.new do |s|
  s.name = "RNTesterSpec"
  # ...
  use_react_native_codegen!(s, { :srcs_dir => __dir__, :modules_output_dir => __dir__ })
end
```

Changelog:
[Internal]

Reviewed By: fkgozali

Differential Revision: D25738466

fbshipit-source-id: c68f5a3cd0996283a7af287e992e2f973024f44c

packages/rn-tester/Podfile.lock

@@ -798,7 +798,7 @@ SPEC CHECKSUMS:
   CocoaLibEvent: 2fab71b8bd46dd33ddb959f7928ec5909f838e3f
   DoubleConversion: cde416483dac037923206447da6e1454df403714
   FBLazyVector: fe973c09b2299b5e8154186ecf1f6554b4f70987
-  FBReactNativeSpec: cc83b1f9c1a764577c37a7009d002b8afb36f192
+  FBReactNativeSpec: d0504078deb2ffa0fbee5032382f4ef165a1c8a8
   Flipper: be611d4b742d8c87fbae2ca5f44603a02539e365
   Flipper-DoubleConversion: 38631e41ef4f9b12861c67d17cb5518d06badc41
   Flipper-Folly: e4493b013c02d9347d5e0cb4d128680239f6c78a

scripts/generate-specs.sh

@@ -8,8 +8,16 @@
 # native modules and components, then uses react-native-codegen
 # to generate native code.
 #
+# Optionally, set these envvars to override defaults:
+# - SRCS_DIR: Path to JavaScript sources
+# - CODEGEN_MODULES_LIBRARY_NAME: Defaults to FBReactNativeSpec
+# - CODEGEN_MODULES_OUTPUT_DIR: Defaults to Libraries/$CODEGEN_MODULES_LIBRARY_NAME/$CODEGEN_MODULES_LIBRARY_NAME
+# - CODEGEN_COMPONENTS_LIBRARY_NAME: Defaults to rncore
+# - CODEGEN_COMPONENTS_OUTPUT_DIR: Defaults to ReactCommon/react/renderer/components/$CODEGEN_COMPONENTS_LIBRARY_NAME
+#
 # Usage:
 #   ./scripts/generate-specs.sh
+#   SRCS_DIR=myapp/js CODEGEN_MODULES_LIBRARY_NAME=MySpecs CODEGEN_MODULES_OUTPUT_DIR=myapp/MySpecs ./scripts/generate-specs.sh
 #
 
 # shellcheck disable=SC2038
@@ -33,12 +41,16 @@ describe () {
 }
 
 main() {
-  SRCS_DIR=$(cd "$RN_DIR/Libraries" && pwd)
+  SRCS_DIR=${SRCS_DIR:-$(cd "$RN_DIR/Libraries" && pwd)}
+  CODEGEN_MODULES_LIBRARY_NAME=${CODEGEN_MODULES_LIBRARY_NAME:-FBReactNativeSpec}
 
-  OUTPUT_DIR="$TEMP_DIR/out"
-  COMPONENTS_DIR="$RN_DIR/ReactCommon/react/renderer/components/rncore"
-  MODULES_DIR="$RN_DIR/Libraries/FBReactNativeSpec/FBReactNativeSpec"
+  CODEGEN_COMPONENTS_LIBRARY_NAME=${CODEGEN_COMPONENTS_LIBRARY_NAME:-rncore}
+  CODEGEN_MODULES_OUTPUT_DIR=${CODEGEN_MODULES_OUTPUT_DIR:-"$RN_DIR/Libraries/$CODEGEN_MODULES_LIBRARY_NAME/$CODEGEN_MODULES_LIBRARY_NAME"}
+  # TODO: $CODEGEN_COMPONENTS_PATH should be programmatically specified, and may change with use_frameworks! support.
+  CODEGEN_COMPONENTS_PATH="ReactCommon/react/renderer/components"
+  CODEGEN_COMPONENTS_OUTPUT_DIR=${CODEGEN_COMPONENTS_OUTPUT_DIR:-"$RN_DIR/$CODEGEN_COMPONENTS_PATH/$CODEGEN_COMPONENTS_LIBRARY_NAME"}
 
+  TEMP_OUTPUT_DIR="$TEMP_DIR/out"
   SCHEMA_FILE="$TEMP_DIR/schema.json"
 
   CODEGEN_REPO_PATH="$RN_DIR/packages/react-native-codegen"
@@ -66,13 +78,13 @@ main() {
 
   describe "Generating native code from schema (iOS)"
   pushd "$RN_DIR" >/dev/null || exit
-    "$YARN_BINARY" --silent node scripts/generate-specs-cli.js ios "$SCHEMA_FILE" "$OUTPUT_DIR"
+    "$YARN_BINARY" --silent node scripts/generate-specs-cli.js ios "$SCHEMA_FILE" "$TEMP_OUTPUT_DIR" "$CODEGEN_MODULES_LIBRARY_NAME"
   popd >/dev/null || exit
 
-  mkdir -p "$COMPONENTS_DIR" "$MODULES_DIR"
-  mv "$OUTPUT_DIR/FBReactNativeSpec.h" "$OUTPUT_DIR/FBReactNativeSpec-generated.mm" "$MODULES_DIR"
-  find "$OUTPUT_DIR" -type f | xargs sed -i '' 's/FBReactNativeSpec/rncore/g'
-  cp -R "$OUTPUT_DIR/." "$COMPONENTS_DIR"
+  mkdir -p "$CODEGEN_COMPONENTS_OUTPUT_DIR" "$CODEGEN_MODULES_OUTPUT_DIR"
+  mv "$TEMP_OUTPUT_DIR/$CODEGEN_MODULES_LIBRARY_NAME.h" "$TEMP_OUTPUT_DIR/$CODEGEN_MODULES_LIBRARY_NAME-generated.mm" "$CODEGEN_MODULES_OUTPUT_DIR"
+  find "$TEMP_OUTPUT_DIR" -type f | xargs sed -i '' "s/$CODEGEN_MODULES_LIBRARY_NAME/$CODEGEN_COMPONENTS_LIBRARY_NAME/g"
+  cp -R "$TEMP_OUTPUT_DIR/." "$CODEGEN_COMPONENTS_OUTPUT_DIR"
 }
 
 trap cleanup EXIT

scripts/react_native_pods.rb

@@ -153,30 +153,36 @@ def use_react_native_codegen!(spec, options={})
   srcs_dir = options[:srcs_dir] ||= File.join(prefix, "Libraries")
 
   # Library name (e.g. FBReactNativeSpec)
-  library_name = spec.name
-  modules_output_dir = File.join(prefix, "Libraries/#{library_name}/#{library_name}")
+  codegen_modules_library_name = spec.name
+  codegen_modules_output_dir = options[:codegen_modules_output_dir] ||= File.join(prefix, "Libraries/#{codegen_modules_library_name}/#{codegen_modules_library_name}")
 
   # Run the codegen as part of the Xcode build pipeline.
+  env_vars = "SRCS_DIR=#{srcs_dir}"
+  env_vars += " CODEGEN_MODULES_OUTPUT_DIR=#{codegen_modules_output_dir}"
+  if ENV['USE_FABRIC'] == '1'
+    # We use a different library name for components, as well as an additional set of files.
+    # Eventually, we want these to be part of the same library as #{codegen_modules_library_name} above.
+    codegen_components_library_name = "rncore"
+    codegen_components_output_dir = File.join(prefix, "ReactCommon/react/renderer/components/#{codegen_components_library_name}")
+    env_vars += " CODEGEN_COMPONENTS_OUTPUT_DIR=#{codegen_components_output_dir}"
+  end
   spec.script_phase = {
     :name => 'Generate Specs',
     :input_files => [srcs_dir],
-    :output_files => ["$(DERIVED_FILE_DIR)/codegen.log"],
-    :script => "sh '#{File.join(__dir__, "generate-specs.sh")}' | tee \"${SCRIPT_OUTPUT_FILE_0}\"",
-    :execution_position => :before_compile
+    :output_files => ["$(DERIVED_FILE_DIR)/codegen-#{codegen_modules_library_name}.log"],
+    :script => "bash -c '#{env_vars} CODEGEN_MODULES_LIBRARY_NAME=#{codegen_modules_library_name} #{File.join(__dir__, "generate-specs.sh")}' | tee \"${SCRIPT_OUTPUT_FILE_0}\"",
+    :execution_position => :before_compile,
+    :show_env_vars_in_log => true
   }
 
   # Since the generated files are not guaranteed to exist when CocoaPods is run, we need to create
   # empty files to ensure the references are included in the resulting Pods Xcode project.
-  mkdir_command = "mkdir -p #{modules_output_dir}"
-  generated_filenames = [ "#{library_name}.h", "#{library_name}-generated.mm" ]
-  generated_files = generated_filenames.map { |filename| File.join(modules_output_dir, filename) }
+  mkdir_command = "mkdir -p #{codegen_modules_output_dir}"
+  generated_filenames = [ "#{codegen_modules_library_name}.h", "#{codegen_modules_library_name}-generated.mm" ]
+  generated_files = generated_filenames.map { |filename| File.join(codegen_modules_output_dir, filename) }
 
   if ENV['USE_FABRIC'] == '1'
-    # We use a different library name for components, as well as an additional set of files.
-    # Eventually, we want these to be part of the same library as #{library_name} above.
-    components_library_name = "rncore"
-    components_output_dir = File.join(prefix, "ReactCommon/react/renderer/components/#{components_library_name}")
-    mkdir_command += " #{components_output_dir}"
+    mkdir_command += " #{codegen_components_output_dir}"
     components_generated_filenames = [
       "ComponentDescriptors.h",
       "EventEmitters.cpp",
@@ -187,7 +193,7 @@ def use_react_native_codegen!(spec, options={})
       "ShadowNodes.cpp",
       "ShadowNodes.h"
     ]
-    generated_files = generated_files.concat(components_generated_filenames.map { |filename| File.join(components_output_dir, filename) })
+    generated_files = generated_files.concat(components_generated_filenames.map { |filename| File.join(codegen_components_output_dir, filename) })
   end
 
   spec.prepare_command = "#{mkdir_command} && touch #{generated_files.reduce() { |str, file| str + " " + file }}"