Make it easier to use CocoaPods to Add2App for iOS (#23021)

* Make it easier to Add2App for iOS

* Use local engine if xcconfig says so

* newline

packages/flutter_tools/bin/xcode_backend.sh

@@ -88,15 +88,24 @@ BuildApp() {
 
   RunCommand rm -rf -- "${derived_dir}/App.framework"
 
+  local local_engine_flag=""
+  local flutter_framework="${framework_path}/Flutter.framework"
+  local flutter_podspec="${framework_path}/Flutter.podspec"
+  if [[ -n "$LOCAL_ENGINE" ]]; then
+    local_engine_flag="--local-engine=${LOCAL_ENGINE}"
+    flutter_framework="${LOCAL_ENGINE}/Flutter.framework"
+    flutter_podspec="${LOCAL_ENGINE}/Flutter.podspec"
+  fi
+
   if [[ -e "${project_path}/.ios" ]]; then
     RunCommand rm -rf -- "${derived_dir}/engine"
     mkdir "${derived_dir}/engine"
-    RunCommand cp -r -- "${framework_path}/Flutter.podspec" "${derived_dir}/engine"
+    RunCommand cp -r -- ${flutter_podspec} "${derived_dir}/engine"
-    RunCommand cp -r -- "${framework_path}/Flutter.framework" "${derived_dir}/engine"
+    RunCommand cp -r -- ${flutter_framework} "${derived_dir}/engine"
     RunCommand find "${derived_dir}/engine/Flutter.framework" -type f -exec chmod a-w "{}" \;
   else
     RunCommand rm -rf -- "${derived_dir}/Flutter.framework"
-    RunCommand cp -r -- "${framework_path}/Flutter.framework" "${derived_dir}"
+    RunCommand cp -r -- ${flutter_framework} "${derived_dir}"
     RunCommand find "${derived_dir}/Flutter.framework" -type f -exec chmod a-w "{}" \;
   fi
 
@@ -110,10 +119,6 @@ BuildApp() {
   fi
 
   local build_dir="${FLUTTER_BUILD_DIR:-build}"
-  local local_engine_flag=""
-  if [[ -n "$LOCAL_ENGINE" ]]; then
-    local_engine_flag="--local-engine=$LOCAL_ENGINE"
-  fi
 
   local track_widget_creation_flag=""
   if [[ -n "$TRACK_WIDGET_CREATION" ]]; then
@@ -296,6 +301,44 @@ ThinAppFrameworks() {
   done
 }
 
+# Adds the App.framework as an embedded binary and the flutter_assets as
+# resources.
+EmbedFlutterFrameworks() {
+  AssertExists "${FLUTTER_APPLICATION_PATH}"
+
+  # Prefer the hidden .ios folder, but fallback to a visible ios folder if .ios
+  # doesn't exist.
+  local flutter_ios_out_folder="${FLUTTER_APPLICATION_PATH}/.ios/Flutter"
+  if [[ ! -d ${flutter_ios_out_folder} ]]; then
+    flutter_ios_out_folder="${FLUTTER_APPLICATION_PATH}/ios/Flutter"
+  fi
+
+  AssertExists "${flutter_ios_out_folder}"
+
+  # Copy the flutter_assets to the Application's resources.
+  AssertExists "${CONFIGURATION_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/"
+  RunCommand cp -r -- "${flutter_ios_out_folder}/flutter_assets" "${CONFIGURATION_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/"
+
+  # Embed App.framework from Flutter into the app (after creating the Frameworks directory
+  # if it doesn't already exist).
+  local xcode_frameworks_dir=${BUILT_PRODUCTS_DIR}"/"${PRODUCT_NAME}".app/Frameworks"
+  RunCommand mkdir -p -- "${xcode_frameworks_dir}"
+  RunCommand cp -Rv -- "${flutter_ios_out_folder}/App.framework" "${xcode_frameworks_dir}"
+
+  # Embed the actual Flutter.framework that the Flutter app expects to run against,
+  # which could be a local build or an arch/type specific build.
+  # Remove it first since Xcode might be trying to hold some of these files - this way we're 
+  # sure to get a clean copy.
+  RunCommand rm -rf -- "${xcode_frameworks_dir}/Flutter.framework"
+  RunCommand cp -Rv -- "${flutter_ios_out_folder}/engine/Flutter.framework" "${xcode_frameworks_dir}/"
+  
+  # Sign the binaries we moved.
+  local identity="${EXPANDED_CODE_SIGN_IDENTITY_NAME:-$CODE_SIGN_IDENTITY}"
+
+  RunCommand codesign --force --verbose --sign "${identity}" -- "${xcode_frameworks_dir}/App.framework/App"
+  RunCommand codesign --force --verbose --sign "${identity}" -- "${xcode_frameworks_dir}/Flutter.framework/Flutter"
+}
+
 # Main entry point.
 
 # TODO(cbracken): improve error handling, then enable set -e
@@ -309,5 +352,7 @@ else
       BuildApp ;;
     "thin")
       ThinAppFrameworks ;;
+    "embed")
+      EmbedFlutterFrameworks ;;
   esac
 fi

packages/flutter_tools/templates/module/ios/library/Flutter.tmpl/podhelper.rb

@@ -33,6 +33,8 @@ def flutter_root(f)
     }
 end
 
+# If this wasn't specified, assume it's two levels up from the directory of this script.
+flutter_application_path ||= File.join(__dir__, '..', '..')
 framework_dir = File.join(flutter_application_path, '.ios', 'Flutter')
 
 engine_dir = File.join(framework_dir, 'engine')
@@ -56,3 +58,18 @@ plugin_pods.map { |r|
     File.symlink(r[:path], symlink)
     pod r[:name], :path => File.join(symlink, 'ios')
 }
+
+# Ensure that ENABLE_BITCODE is set to NO, add a #include to Generated.xcconfig, and
+# add a run script to the Build Phases.
+# TODO(dnfield): Figure out a way to deliver the Build Phase scripts without manual user intervention.
+post_install do |installer|
+    installer.pods_project.targets.each do |target|
+        target.build_configurations.each do |config|
+            config.build_settings['ENABLE_BITCODE'] = 'NO'
+            xcconfig_path = config.base_configuration_reference.real_path
+            File.open(xcconfig_path, 'a+') do |file|
+                file.puts "#include \"#{File.join(framework_dir, 'Generated.xcconfig')}\""
+            end
+        end
+    end
+end