Initial Linux GN build

.gitignore

@@ -1 +1,2 @@
+out/
 .DS_Store

.gn

@@ -0,0 +1 @@
+buildconfig = "//build/BUILDCONFIG.gn"

BUILD.gn

@@ -0,0 +1,22 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+group("gn_all") {
+  deps = [
+    "//library:flutter_embedder",
+    "//plugins/color_panel:color_panel",
+    "//plugins/file_chooser:file_chooser",
+    "//plugins/menubar:menubar",
+  ]
+}

build/BUILD.gn

@@ -0,0 +1,32 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+config("defaults") {
+  cflags = [
+    "-std=c++14",
+    "-Wall",
+    "-Werror",
+    "-pthread",
+  ]
+  include_dirs = [
+    "//"
+  ]
+}
+
+config("shared_library_defaults") {
+  cflags = [
+    "-shared",
+    "-fPIC",
+  ]
+}

build/BUILDCONFIG.gn

@@ -0,0 +1,42 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set_default_toolchain("//third_party/chromium/build/toolchain:gcc")
+
+set_defaults("executable") {
+  configs = [ "//build:defaults" ]
+}
+set_defaults("static_library") {
+  configs = [ "//build:defaults" ]
+}
+set_defaults("shared_library") {
+  configs = [ "//build:defaults", "//build:shared_library_defaults" ]
+}
+set_defaults("published_shared_library") {
+  configs = [ "//build:defaults", "//build:shared_library_defaults" ]
+}
+
+if (host_os == "linux") {
+  is_linux = true
+  is_mac = false
+  is_win = false
+} else if (host_os == "mac") {
+  is_linux = false
+  is_mac = true
+  is_win = false
+} else if (host_os == "win") {
+  is_linux = false
+  is_mac = false
+  is_win = true
+}

build/flutter.gni

@@ -0,0 +1,21 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+declare_args() {
+  # The path to the Flutter tree to use for any Flutter operations or assets.
+  # If empty, assumes a directory called 'flutter' that is a sibling of this
+  # repository (like tools/flutter_location; this duplication avoids shelling
+  # out).
+  flutter_tree_path = rebase_path("../../flutter")
+}

build/linux/config/BUILD.gn

@@ -0,0 +1,31 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//third_party/chromium/build/config/linux/pkg_config.gni")
+
+pkg_config("gtk3") {
+  packages = [ "gtk+-3.0" ]
+}
+
+pkg_config("epoxy") {
+  packages = [ "epoxy" ]
+}
+
+pkg_config("x11") {
+  packages = [ "x11" ]
+}
+
+pkg_config("jsoncpp") {
+  packages = [ "jsoncpp" ]
+}

build/packaging.gni

@@ -0,0 +1,60 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Puts the public headers of the invoker in public_header_subdir
+# under the top-level include/ directory in the build output.
+#
+# This is intended to make consuming public headers of all the libraries built
+# by GN easy for outside build systems on Linux, by requiring only a single
+# include directory.
+if (is_linux) {
+  template("copy_includes") {
+    copy(target_name) {
+      assert(defined(invoker.sources),
+            "|sources| must be provided for copy_includes.")
+      forward_variables_from(invoker, [ "deps", "sources", "subdir" ])
+      output_dir = "$root_out_dir/include"
+      if (defined(subdir)) {
+        output_dir = "$output_dir/$subdir"
+      }
+      outputs = [ "$output_dir/{{source_file_part}}"]
+    }
+  }
+}
+
+# An abstraction for a shared library with associated headers that is intended
+# to be consumed from the build output.
+#
+# On Linux, this performs a copy_includes in addition to building the library.
+template("published_shared_library") {
+  template_target_name = target_name
+
+  if (is_linux) {
+    copy_includes("_publish_${template_target_name}_headers") {
+      sources = invoker.public
+      subdir = invoker.public_header_subdir
+    }
+
+    shared_library(template_target_name) {
+      forward_variables_from(invoker, "*")
+      assert(defined(public),
+            "|public| must be provided for published_shared_library.")
+
+      if (!defined(deps)) {
+        deps = []
+      }
+      deps += [ ":_publish_${template_target_name}_headers" ]
+    }
+  }
+}

example/linux/Makefile

@@ -58,6 +58,29 @@ BIN_OUT=$(OUT_DIR)/flutter_embedder_example
 ICU_DATA_OUT=$(OUT_DATA_DIR)/$(ICU_DATA_NAME)
 ALL_LIBS_OUT=$(foreach lib,$(ALL_LIBS),$(OUT_LIB_DIR)/$(notdir $(lib)))
 
+# Overrides for the optional GN build.
+ifdef USE_GN
+GN_OUT_DIR=$(PROJECT_ROOT)/out
+# Use GN's out dir even though this isn't a GN build, to group build output.
+OUT_DIR=$(GN_OUT_DIR)/example
+
+# The GN build places all libraries at the top level of the output directory.
+FLUTTER_EMBEDDER_LIB=$(GN_OUT_DIR)/lib$(FLUTTER_EMBEDDER_LIB_NAME).so
+FLUTTER_ENGINE_LIB=$(GN_OUT_DIR)/lib$(FLUTTER_ENGINE_LIB_NAME).so
+PLUGIN_LIBS=$(foreach plugin,$(PLUGIN_NAMES)\
+	,$(GN_OUT_DIR)/lib$(PLUGIN_LIB_NAME_PREFIX)$(plugin).so)
+
+# The GN build places all published headers in a top-level include/.
+INCLUDE_DIRS=$(GN_OUT_DIR)/include
+
+# Override LIBRARY_DIRS since it's used for controlling the external build.
+LIBRARY_DIRS=$(GN_OUT_DIR)
+
+# Additional tools
+GN_WRAPPER=$(TOOLS_DIR)/gn_dart
+NINJA_BIN=ninja
+endif
+
 # Build settings
 CXX=g++ -std=c++14
 CXXFLAGS=-Wall -Werror $(shell pkg-config --cflags jsoncpp)
@@ -85,6 +108,12 @@ $(BIN_OUT): $(SOURCES) $(ALL_LIBS_OUT)
 	$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(SOURCES) $(LDFLAGS) -o $@
 
 # Depedency directories are used as phony targets to invoke their builds.
+ifdef USE_GN
+.PHONY: $(LIBRARY_DIRS)
+$(LIBRARY_DIRS):
+	$(GN_WRAPPER) gen $(GN_OUT_DIR)
+	$(NINJA_BIN) -C $(GN_OUT_DIR) $(FLUTTER_EMBEDDER_LIB_NAME) $(PLUGIN_NAMES)
+else
 .PHONY: $(LIBRARY_DIRS)
 $(LIBRARY_DIRS):
 	$(MAKE) -C $@ $(MAKECMDGOALS)
@@ -93,6 +122,7 @@ $(LIBRARY_DIRS):
 # in parallel in the event that someone supplies the -j flag to `make`.
 # TODO: Fix this in the plugin builds so that it's not necessary at this layer.
 $(PLUGIN_DIRS): $(FLUTTER_EMBEDDER_LIB_DIR)
+endif
 
 # Require that all the library builds run for anything depending on the
 # libraries, but use order-only so that the phony build targets don't trigger

library/BUILD.gn

@@ -0,0 +1,94 @@
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build/flutter.gni")
+import("//build/packaging.gni")
+import("//library/engine.gni")
+
+published_shared_library("flutter_embedder") {
+  if (is_linux) {
+    sources = [
+      "linux/src/internal/engine_method_result.cc",
+      "linux/src/internal/engine_method_result.h",
+      "linux/src/internal/json_message_codec.cc",
+      "linux/src/internal/json_message_codec.h",
+      "linux/src/internal/keyboard_hook_handler.h",
+      "linux/src/internal/plugin_handler.cc",
+      "linux/src/internal/plugin_handler.h",
+      "linux/src/internal/text_input_model.cc",
+      "linux/src/internal/text_input_model.h",
+      "linux/src/internal/text_input_plugin.cc",
+      "linux/src/internal/text_input_plugin.h",
+      "linux/src/embedder.cc",
+      "linux/src/json_method_call.cc",
+      "linux/src/json_method_codec.cc",
+      "linux/src/json_plugin.cc",
+      "linux/src/method_call.cc",
+      "linux/src/method_channel.cc",
+      "linux/src/method_codec.cc",
+      "linux/src/method_result.cc",
+      "linux/src/plugin.cc",
+    ]
+    public = [
+      "linux/include/flutter_desktop_embedding/binary_messenger.h",
+      "linux/include/flutter_desktop_embedding/embedder.h",
+      "linux/include/flutter_desktop_embedding/json_method_call.h",
+      "linux/include/flutter_desktop_embedding/json_method_codec.h",
+      "linux/include/flutter_desktop_embedding/json_plugin.h",
+      "linux/include/flutter_desktop_embedding/method_call.h",
+      "linux/include/flutter_desktop_embedding/method_channel.h",
+      "linux/include/flutter_desktop_embedding/method_codec.h",
+      "linux/include/flutter_desktop_embedding/method_result.h",
+      "linux/include/flutter_desktop_embedding/plugin.h",
+    ]
+  }
+
+  deps = [
+    ":fetch_flutter_engine",
+  ]
+
+  if (is_linux) {
+    public_header_subdir = "flutter_desktop_embedding"
+
+    deps += [
+      "//library/linux:publish_flutter_engine",
+    ]
+
+    libs = [
+      "glfw",
+      "GL",
+    ]
+
+    configs += [
+      "//build/linux/config:epoxy",
+      "//build/linux/config:gtk3",
+      "//build/linux/config:jsoncpp",
+      "//build/linux/config:x11",
+    ]
+
+    public_configs = [
+      "//library/linux:relative_public_headers",
+    ]
+  }
+}
+
+action("fetch_flutter_engine") {
+  script = "//tools/dart_tools/bin/update_flutter_engine.dart"
+  inputs = [ "$flutter_tree_path/bin/internal/engine.version" ]
+  outputs = engine_files
+  args = [
+    "--flutter_root=$flutter_tree_path",
+    rebase_path(engine_download_dir, root_build_dir),
+  ]
+}