Add Go build support for GN.

Provide a skeleton of the mojo system API, as well as a skeleton test.
R=qsr@chromium.org, brettw@chromium.org, viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/556813003

Cr-Commit-Position: refs/heads/master@{#297038}

build/go/go.py

+#!/usr/bin/env python
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This script invokes the go build tool.
+Must be called as follows:
+python go.py <go-binary> <build directory> <output file> <src directory>
+<CGO_CFLAGS> <CGO_LDFLAGS> <go-binary options>
+eg.
+python go.py /usr/lib/google-golang/bin/go out/build out/a.out .. "-I."
+"-L. -ltest" test -c test/test.go
+"""
+
+import argparse
+import os
+import shutil
+import sys
+
+def main():
+  parser = argparse.ArgumentParser()
+  parser.add_argument('go_binary')
+  parser.add_argument('build_directory')
+  parser.add_argument('output_file')
+  parser.add_argument('src_root')
+  parser.add_argument('cgo_cflags')
+  parser.add_argument('cgo_ldflags')
+  parser.add_argument('go_option', nargs='*')
+  args = parser.parse_args()
+  go_binary = args.go_binary
+  build_dir = args.build_directory
+  out_file = os.path.abspath(args.output_file)
+  # The src directory specified is relative. We need this as an absolute path.
+  src_root = os.path.abspath(args.src_root)
+  # GOPATH must be absolute, and point to one directory up from |src_Root|
+  go_path = os.path.abspath(os.path.join(src_root, ".."))
+  go_options = args.go_option
+  try:
+    shutil.rmtree(build_dir, True)
+    os.mkdir(build_dir)
+  except:
+    pass
+  old_directory = os.getcwd()
+  os.chdir(build_dir)
+  os.environ["GOPATH"] = go_path
+  os.environ["CGO_CFLAGS"] = args.cgo_cflags
+  os.environ["CGO_LDFLAGS"] = args.cgo_ldflags
+  os.system("%s %s" % (go_binary, " ".join(go_options)))
+  out_files = [ f for f in os.listdir(".") if os.path.isfile(f)]
+  if (len(out_files) > 0):
+    shutil.move(out_files[0], out_file)
+  os.chdir(old_directory)
+  try:
+    shutil.rmtree(build_dir, True)
+  except:
+    pass
+
+if __name__ == '__main__':
+  sys.exit(main())

build/go/rules.gni

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+declare_args() {
+  # By default, there is no go build tool, because go builds are not supported.
+  go_build_tool = ""
+}
+
+# Declare a go test binary target.
+#
+# The target generates a go test executable, linking against other C code,
+# which is compiled into a static library and linked against Go.
+#
+# Only works on linux. |go_build_tool| must be set to the absolute path
+# of the go build tool.
+#
+# Variables (all required)
+#   sources: list of .go files to compile
+#   static_library_sources: list of C sources needed for the static library
+#   deps: dependencies for the static library
+
+template("go_test_binary") {
+  # Only available on linux for now.
+  assert(is_linux)
+  assert(defined(invoker.sources))
+  assert(go_build_tool != "")
+
+  static_library_name = target_name + "_static_library"
+
+  static_library(static_library_name) {
+    sources = invoker.static_library_sources
+    deps = invoker.deps
+    complete_static_lib = true
+  }
+
+  action(target_name) {
+    deps = [
+      ":$static_library_name",
+    ]
+    script = "//build/go/go.py"
+    outputs = [ "${target_out_dir}/${target_name}" ]
+    # Since go test does not permit specifying an output directory or output
+    # binary name, we create a temporary build directory, and the python
+    # script will later identify the output, copy it to the target location,
+    # and clean up the temporary build directory.
+    build_dir = "${target_out_dir}/${target_name}_build"
+    args = [
+      "--", 
+      "${go_build_tool}",
+      rebase_path(build_dir, root_build_dir),
+      rebase_path(target_out_dir, root_build_dir) + "/${target_name}",
+      rebase_path("//", root_build_dir),
+      "-I" + rebase_path("//"),
+      " -L" + rebase_path(target_out_dir) +
+      " -L" + rebase_path(root_build_dir + "/obj/third_party/libevent") +
+      " -l" + static_library_name +
+      " -lstdc++ -lpthread -lm -lglib-2.0 -levent",
+      "test", "-c",
+    ] + rebase_path(invoker.sources, build_dir)
+  }
+}

mojo/BUILD.gn

@@ -7,6 +7,9 @@ import("//build/config/ui.gni")
 group("mojo") {
   # Meta-target, don't link into production code.
   testonly = true
+  declare_args() {
+    mojo_use_go = false
+  }
   deps = [
     ":tests",
     "//mojo/apps/js:mojo_js",
@@ -22,6 +25,11 @@ group("mojo") {
     deps += [
       "//mojo/python",
     ]
+    if (mojo_use_go) {
+      deps += [
+        "//mojo/go",
+      ]
+    }
   }
 }
 

mojo/go/BUILD.gn

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/go/rules.gni")
+
+group("go") {
+  deps = [
+    ":system_test",
+  ]
+}
+
+go_test_binary("system_test") {
+  sources = [
+    "tests/system_test.go",
+  ]
+  static_library_sources = [
+    "c_embedder/c_embedder.cc",
+    "c_embedder/c_embedder.h",
+  ]
+  deps = [
+    "//mojo/system",
+  ]
+}

mojo/go/c_embedder/c_embedder.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/go/c_embedder/c_embedder.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "mojo/embedder/embedder.h"
+#include "mojo/embedder/simple_platform_support.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void InitializeMojoEmbedder() {
+  mojo::embedder::Init(scoped_ptr<mojo::embedder::PlatformSupport>(
+      new mojo::embedder::SimplePlatformSupport()));
+}
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif

mojo/go/c_embedder/c_embedder.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MOJO_GO_C_EMBEDDER_C_EMBEDDER_H_
+#define MOJO_GO_C_EMBEDDER_C_EMBEDDER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+__attribute__((visibility("default"))) void InitializeMojoEmbedder();
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // MOJO_GO_C_EMBEDDER_C_EMBEDDER_H__

mojo/go/system/embedder/embedder.go

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package embedder;
+
+/*
+#include "mojo/go/c_embedder/c_embedder.h"
+*/
+import "C"
+
+func InitializeMojoEmbedder() {
+	C.InitializeMojoEmbedder();
+}

mojo/go/system/impl/core_impl.go

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package impl;
+
+/*
+#include "mojo/public/platform/native/system_thunks.h"
+*/
+import "C"
+import "mojo/public/go/mojo/system"
+
+
+type CoreImpl struct {
+}
+
+func (c CoreImpl) GetTimeTicksNow() int64 {
+	return (int64)(C.MojoGetTimeTicksNow());
+}
+
+var lazyInstance *CoreImpl = nil;
+
+func GetCore() system.Core {
+	if lazyInstance == nil {
+		lazyInstance = new(CoreImpl);
+	}
+	return lazyInstance;
+}

mojo/go/tests/system_test.go

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package tests
+
+import "mojo/go/system/embedder"
+import "mojo/go/system/impl"
+import "mojo/public/go/mojo/system"
+import "testing"
+
+func Init() {
+	embedder.InitializeMojoEmbedder();
+}
+
+func TestGetTimeTicksNow(t *testing.T) {
+	Init();
+	var c system.Core = impl.GetCore();
+	x := c.GetTimeTicksNow();
+	if (x < 10) {
+		t.Error("Invalid GetTimeTicksNow return value");
+	}
+}

mojo/public/go/mojo/system/core.go

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package system;
+
+type Core interface {
+	GetTimeTicksNow() int64
+}

mojo/public/platform/native/system_thunks.h

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Note: This header should be compilable as C.
+
 #ifndef MOJO_PUBLIC_PLATFORM_NATIVE_SYSTEM_THUNKS_H_
 #define MOJO_PUBLIC_PLATFORM_NATIVE_SYSTEM_THUNKS_H_
 
@@ -43,9 +45,10 @@ struct MojoSystemThunks {
                          const MojoHandleSignals* signals,
                          uint32_t num_handles,
                          MojoDeadline deadline);
-  MojoResult (*CreateMessagePipe)(const MojoCreateMessagePipeOptions* options,
-                                  MojoHandle* message_pipe_handle0,
-                                  MojoHandle* message_pipe_handle1);
+  MojoResult (*CreateMessagePipe)(
+      const struct MojoCreateMessagePipeOptions* options,
+      MojoHandle* message_pipe_handle0,
+      MojoHandle* message_pipe_handle1);
   MojoResult (*WriteMessage)(MojoHandle message_pipe_handle,
                              const void* bytes,
                              uint32_t num_bytes,
@@ -58,7 +61,7 @@ struct MojoSystemThunks {
                             MojoHandle* handles,
                             uint32_t* num_handles,
                             MojoReadMessageFlags flags);
-  MojoResult (*CreateDataPipe)(const MojoCreateDataPipeOptions* options,
+  MojoResult (*CreateDataPipe)(const struct MojoCreateDataPipeOptions* options,
                                MojoHandle* data_pipe_producer_handle,
                                MojoHandle* data_pipe_consumer_handle);
   MojoResult (*WriteData)(MojoHandle data_pipe_producer_handle,
@@ -82,12 +85,12 @@ struct MojoSystemThunks {
   MojoResult (*EndReadData)(MojoHandle data_pipe_consumer_handle,
                             uint32_t num_elements_read);
   MojoResult (*CreateSharedBuffer)(
-      const MojoCreateSharedBufferOptions* options,
+      const struct MojoCreateSharedBufferOptions* options,
       uint64_t num_bytes,
       MojoHandle* shared_buffer_handle);
   MojoResult (*DuplicateBufferHandle)(
       MojoHandle buffer_handle,
-      const MojoDuplicateBufferHandleOptions* options,
+      const struct MojoDuplicateBufferHandleOptions* options,
       MojoHandle* new_buffer_handle);
   MojoResult (*MapBuffer)(MojoHandle buffer_handle,
                           uint64_t offset,
@@ -98,6 +101,8 @@ struct MojoSystemThunks {
 };
 #pragma pack(pop)
 
+
+#ifdef __cplusplus
 // Intended to be called from the embedder. Returns a |MojoCore| initialized
 // to contain pointers to each of the embedder's MojoCore functions.
 inline MojoSystemThunks MojoMakeSystemThunks() {
@@ -124,6 +129,8 @@ inline MojoSystemThunks MojoMakeSystemThunks() {
   };
   return system_thunks;
 }
+#endif
+
 
 // Use this type for the function found by dynamically discovering it in
 // a DSO linked with mojo_system. For example:
@@ -132,6 +139,7 @@ inline MojoSystemThunks MojoMakeSystemThunks() {
 //         "MojoSetSystemThunks"));
 // The expected size of |system_thunks} is returned.
 // The contents of |system_thunks| are copied.
-typedef size_t (*MojoSetSystemThunksFn)(const MojoSystemThunks* system_thunks);
+typedef size_t (*MojoSetSystemThunksFn)(
+    const struct MojoSystemThunks* system_thunks);
 
 #endif  // MOJO_PUBLIC_PLATFORM_NATIVE_SYSTEM_THUNKS_H_