GN threading refactor

tools/gn/loader_unittest.cc

Index: tools/gn/loader_unittest.cc
diff --git a/tools/gn/loader_unittest.cc b/tools/gn/loader_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7aa267dc55226375649b20766018ec4caa09b5fb
--- /dev/null
+++ b/tools/gn/loader_unittest.cc
@@ -0,0 +1,191 @@
+// Copyright (c) 2013 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 <map>
+#include <utility>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/memory/linked_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tools/gn/build_settings.h"
+#include "tools/gn/err.h"
+#include "tools/gn/loader.h"
+#include "tools/gn/parse_tree.h"
+#include "tools/gn/parser.h"
+#include "tools/gn/scheduler.h"
+#include "tools/gn/tokenizer.h"
+
+namespace {
+
+class MockInputFileManager {
+ public:
+  typedef base::Callback<void(const ParseNode*)> Callback;
+
+  MockInputFileManager() {
+  }
+
+  LoaderImpl::AsyncLoadFileCallback GetCallback();
+
+  // Sets a given response for a given source file.
+  void AddCannedResponse(const SourceFile& source_file,
+                         const std::string& source);
+
+  // Returns true if there is/are pending load(s) matching the given file(s).
+  bool HasOnePending(const SourceFile& f) const;
+  bool HasTwoPending(const SourceFile& f1, const SourceFile& f2) const;
+
+  void IssueAllPending();
+
+ private:
+  struct CannedResult {
+    scoped_ptr<InputFile> input_file;
+    std::vector<Token> tokens;
+    scoped_ptr<ParseNode> root;
+  };
+
+  bool AsyncLoadFile(const LocationRange& origin,
+                     const BuildSettings* build_settings,
+                     const SourceFile& file_name,
+                     const Callback& callback,
+                     Err* err) {
+    pending_.push_back(std::make_pair(file_name, callback));
+    return true;
+  }
+
+  // Owning pointers.
+  typedef std::map<SourceFile, linked_ptr<CannedResult> > CannedResponseMap;
+  CannedResponseMap canned_responses_;
+
+  std::vector< std::pair<SourceFile, Callback> > pending_;
+};
+
+LoaderImpl::AsyncLoadFileCallback MockInputFileManager::GetCallback() {
+  return base::Bind(&MockInputFileManager::AsyncLoadFile,
+                    base::Unretained(this));
+}
+
+// Sets a given response for a given source file.
+void MockInputFileManager::AddCannedResponse(const SourceFile& source_file,
+                                             const std::string& source) {
+  CannedResult* canned = new CannedResult;
+  canned->input_file.reset(new InputFile(source_file));
+  canned->input_file->SetContents(source);
+
+  // Tokenize.
+  Err err;
+  canned->tokens = Tokenizer::Tokenize(canned->input_file.get(), &err);
+  EXPECT_FALSE(err.has_error());
+
+  // Parse.
+  canned->root = Parser::Parse(canned->tokens, &err).Pass();
+  EXPECT_FALSE(err.has_error());
+
+  canned_responses_[source_file] = linked_ptr<CannedResult>(canned);
+}
+
+bool MockInputFileManager::HasOnePending(const SourceFile& f) const {
+  return pending_.size() == 1u && pending_[0].first == f;
+}
+
+bool MockInputFileManager::HasTwoPending(const SourceFile& f1,
+                                         const SourceFile& f2) const {
+  if (pending_.size() != 2u)
+    return false;
+  return pending_[0].first == f1 && pending_[1].first == f2;
+}
+
+void MockInputFileManager::IssueAllPending() {
+  BlockNode block(false);  // Default response.
+
+  for (size_t i = 0; i < pending_.size(); i++) {
+    CannedResponseMap::const_iterator found =
+        canned_responses_.find(pending_[i].first);
+    if (found == canned_responses_.end())
+      pending_[i].second.Run(&block);
+    else
+      pending_[i].second.Run(found->second->root.get());
+  }
+  pending_.clear();
+}
+
+// LoaderTest ------------------------------------------------------------------
+
+class LoaderTest : public testing::Test {
+ public:
+  LoaderTest() {
+    build_settings_.SetBuildDir(SourceDir("//out/Debug/"));
+  }
+  virtual ~LoaderTest() {
+  }
+
+ protected:
+  Scheduler scheduler_;
+  BuildSettings build_settings_;
+  MockInputFileManager mock_ifm_;
+};
+
+}  // namespace
+
+// -----------------------------------------------------------------------------
+
+TEST_F(LoaderTest, Foo) {
+  SourceFile build_config("//build/config/BUILDCONFIG.gn");
+  build_settings_.set_build_config_file(build_config);
+
+  scoped_refptr<LoaderImpl> loader(new LoaderImpl(&build_settings_));
+
+  // The default toolchain needs to be set by the build config file.
+  mock_ifm_.AddCannedResponse(build_config,
+                              "set_default_toolchain(\"//tc:tc\")");
+
+  loader->set_async_load_file(mock_ifm_.GetCallback());
+
+  // Request the root build file be loaded. This should kick off the default
+  // build config loading.
+  SourceFile root_build("//BUILD.gn");
+  loader->Load(root_build, Label());
+  EXPECT_TRUE(mock_ifm_.HasOnePending(build_config));
+
+  // Completing the build config load should kick off the root build file load.
+  mock_ifm_.IssueAllPending();
+  scheduler_.main_loop()->RunUntilIdle();
+  EXPECT_TRUE(mock_ifm_.HasOnePending(root_build));
+
+  // Load the root build file.
+  mock_ifm_.IssueAllPending();
+  scheduler_.main_loop()->RunUntilIdle();
+
+  // Schedule some other file to load in another toolchain.
+  Label second_tc(SourceDir("//tc2/"), "tc2");
+  SourceFile second_file("//foo/BUILD.gn");
+  loader->Load(second_file, second_tc);
+  EXPECT_TRUE(mock_ifm_.HasOnePending(SourceFile("//tc2/BUILD.gn")));
+
+  // Running the toolchain file should schedule the build config file to load
+  // for that toolchain.
+  mock_ifm_.IssueAllPending();
+  scheduler_.main_loop()->RunUntilIdle();
+
+  // We have to tell it we have a toolchain definition now (normally the
+  // builder would do this).
+  const Settings* default_settings = loader->GetToolchainSettings(Label());
+  Toolchain second_tc_object(default_settings, second_tc);
+  loader->ToolchainLoaded(&second_tc_object);
+  EXPECT_TRUE(mock_ifm_.HasOnePending(build_config));
+
+  // Scheduling a second file to load in that toolchain should not make it
+  // pending yet (it's waiting for the build config).
+  SourceFile third_file("//bar/BUILD.gn");
+  loader->Load(third_file, second_tc);
+  EXPECT_TRUE(mock_ifm_.HasOnePending(build_config));
+
+  // Running the build config file should make our third file pending.
+  mock_ifm_.IssueAllPending();
+  scheduler_.main_loop()->RunUntilIdle();
+  EXPECT_TRUE(mock_ifm_.HasTwoPending(second_file, third_file));
+
+  EXPECT_FALSE(scheduler_.is_failed());
+}