Add initial prototype for the GN meta-buildsystem.

tools/gn/target.cc

Index: tools/gn/target.cc
diff --git a/tools/gn/target.cc b/tools/gn/target.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0936f22ba3aea6103433d24a5310b8955819b59b
--- /dev/null
+++ b/tools/gn/target.cc
@@ -0,0 +1,94 @@
+// 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 "tools/gn/target.h"
+
+#include "base/bind.h"
+#include "tools/gn/scheduler.h"
+
+namespace {
+
+void TargetResolvedThunk(const base::Callback<void(const Target*)>& cb,
+                         const Target* t) {
+  cb.Run(t);
+}
+
+}  // namespace
+
+Target::Target(const Settings* settings, const Label& label)
+    : Item(label),
+      settings_(settings),
+      output_type_(NONE),
+      generated_(false),
+      generator_function_(NULL) {
+}
+
+Target::~Target() {
+}
+
+Target* Target::AsTarget() {
+  return this;
+}
+
+const Target* Target::AsTarget() const {
+  return this;
+}
+
+void Target::OnResolved() {
+  // Gather info from our dependents we need.
+  for (size_t dep = 0; dep < deps_.size(); dep++) {
+    // All dependent configs get pulled to us, and to our dependents.
+    const std::vector<const Config*>& all =
+        deps_[dep]->all_dependent_configs();
+    for (size_t i = 0; i < all.size(); i++) {
+      configs_.push_back(all[i]);
+      all_dependent_configs_.push_back(all[i]);
+    }
+
+    // Direct dependent configs get pulled only to us.
+    const std::vector<const Config*>& direct =
+        deps_[dep]->direct_dependent_configs();
+    for (size_t i = 0; i < direct.size(); i++)
+      configs_.push_back(direct[i]);
+
+    // Direct dependent libraries.
+    if (deps_[dep]->output_type() == STATIC_LIBRARY ||
+        deps_[dep]->output_type() == SHARED_LIBRARY ||
+        deps_[dep]->output_type() == LOADABLE_MODULE)
+      inherited_libraries_.insert(deps_[dep]);
+
+    // Inherited libraries. DOn't pull transitive libraries from shared
+    // libraries, since obviously those shouldn't be linked directly into
+    // later deps unless explicitly specified.
+    if (deps_[dep]->output_type() != SHARED_LIBRARY &&
+        deps_[dep]->output_type() != LOADABLE_MODULE &&
+        deps_[dep]->output_type() != EXECUTABLE) {
+      const std::set<const Target*> inherited =
+          deps_[dep]->inherited_libraries();
+      for (std::set<const Target*>::const_iterator i = inherited.begin();
+           i != inherited.end(); ++i)
+        inherited_libraries_.insert(*i);
+    }
+  }
+
+  if (!settings_->build_settings()->target_resolved_callback().is_null()) {
+    g_scheduler->ScheduleWork(base::Bind(&TargetResolvedThunk,
+        settings_->build_settings()->target_resolved_callback(),
+        this));
+  }
+}
+
+bool Target::HasBeenGenerated() const {
+  return generated_;
+}
+
+void Target::SetGenerated(const Token* token) {
+  DCHECK(!generated_);
+  generated_ = true;
+  generator_function_ = token;
+}
+
+bool Target::IsLinkable() const {
+  return output_type_ == STATIC_LIBRARY || output_type_ == SHARED_LIBRARY;
+}