Propagate GN public shared libraries through shared libraries

tools/gn/inherited_libraries.cc

Index: tools/gn/inherited_libraries.cc
diff --git a/tools/gn/inherited_libraries.cc b/tools/gn/inherited_libraries.cc
new file mode 100644
index 0000000000000000000000000000000000000000..06ac9ae4480fb8c2261f624b5e574c29d6480b7a
--- /dev/null
+++ b/tools/gn/inherited_libraries.cc
@@ -0,0 +1,76 @@
+// Copyright 2015 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/inherited_libraries.h"
+
+#include "tools/gn/target.h"
+
+InheritedLibraries::InheritedLibraries() {
+}
+
+InheritedLibraries::~InheritedLibraries() {
+}
+
+std::vector<const Target*> InheritedLibraries::GetOrdered() const {
+  std::vector<const Target*> result;
+  result.resize(map_.size());
+
+  // The indices in the map should be from 0 to the number of items in the
+  // map, so insert directly into the result (with some sanity checks).
+  for (const auto& pair : map_) {
+    size_t index = pair.second.index;
+    DCHECK(index < result.size());
+    DCHECK(!result[index]);
+    result[index] = pair.first;
+  }
+
+  return result;
+}
+
+std::vector<std::pair<const Target*, bool>>
+InheritedLibraries::GetOrderedAndPublicFlag() const {
+  std::vector<std::pair<const Target*, bool>> result;
+  result.resize(map_.size());
+
+  for (const auto& pair : map_) {
+    size_t index = pair.second.index;
+    DCHECK(index < result.size());
+    DCHECK(!result[index].first);
+    result[index] = std::make_pair(pair.first, pair.second.is_public);
+  }
+
+  return result;
+}
+
+void InheritedLibraries::Append(const Target* target, bool is_public) {
+  // Try to insert a new node.
+  auto insert_result = map_.insert(
+      std::make_pair(target, Node(map_.size(), is_public)));
+
+  if (!insert_result.second) {
+    // Element already present, insert failed and insert_result indicates the
+    // old one. The old one may need to have its public flag updated.
+    if (is_public) {
+      Node& existing_node = insert_result.first->second;
+      existing_node.is_public = true;
+    }
+  }
+}
+
+void InheritedLibraries::AppendInherited(const InheritedLibraries& other,
+                                         bool is_public) {
+  // Append all items in order, mark them public only if the're already public
+  // and we're adding them publically.
+  for (const auto& cur : other.GetOrderedAndPublicFlag())
+    Append(cur.first, is_public && cur.second);
+}
+
+void InheritedLibraries::AppendPublicSharedLibraries(
+    const InheritedLibraries& other,
+    bool is_public) {
+  for (const auto& cur : other.GetOrderedAndPublicFlag()) {
+    if (cur.first->output_type() == Target::SHARED_LIBRARY && cur.second)
+      Append(cur.first, is_public);
+  }
+}