Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/src/google/protobuf/stubs/map-util.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// from google3/util/gtl/map-util.h
+// Author: Anton Carver
+
+#ifndef GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__
+#define GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__
+
+#include <google/protobuf/stubs/common.h>
+
+namespace google {
+namespace protobuf {
+
+// Perform a lookup in a map or hash_map.
+// If the key is present in the map then the value associated with that
+// key is returned, otherwise the value passed as a default is returned.
+template <class Collection>
+const typename Collection::value_type::second_type&
+FindWithDefault(const Collection& collection,
+                const typename Collection::value_type::first_type& key,
+                const typename Collection::value_type::second_type& value) {
+  typename Collection::const_iterator it = collection.find(key);
+  if (it == collection.end()) {
+    return value;
+  }
+  return it->second;
+}
+
+// Perform a lookup in a map or hash_map.
+// If the key is present a const pointer to the associated value is returned,
+// otherwise a NULL pointer is returned.
+template <class Collection>
+const typename Collection::value_type::second_type*
+FindOrNull(const Collection& collection,
+           const typename Collection::value_type::first_type& key) {
+  typename Collection::const_iterator it = collection.find(key);
+  if (it == collection.end()) {
+    return 0;
+  }
+  return &it->second;
+}
+
+// Perform a lookup in a map or hash_map, assuming that the key exists.
+// Crash if it does not.
+//
+// This is intended as a replacement for operator[] as an rvalue (for reading)
+// when the key is guaranteed to exist.
+//
+// operator[] is discouraged for several reasons:
+//  * It has a side-effect of inserting missing keys
+//  * It is not thread-safe (even when it is not inserting, it can still
+//      choose to resize the underlying storage)
+//  * It invalidates iterators (when it chooses to resize)
+//  * It default constructs a value object even if it doesn't need to
+//
+// This version assumes the key is printable, and includes it in the fatal log
+// message.
+template <class Collection>
+const typename Collection::value_type::second_type&
+FindOrDie(const Collection& collection,
+          const typename Collection::value_type::first_type& key) {
+  typename Collection::const_iterator it = collection.find(key);
+  GOOGLE_CHECK(it != collection.end()) << "Map key not found: " << key;
+  return it->second;
+}
+
+// Perform a lookup in a map or hash_map whose values are pointers.
+// If the key is present a const pointer to the associated value is returned,
+// otherwise a NULL pointer is returned.
+// This function does not distinguish between a missing key and a key mapped
+// to a NULL value.
+template <class Collection>
+const typename Collection::value_type::second_type
+FindPtrOrNull(const Collection& collection,
+              const typename Collection::value_type::first_type& key) {
+  typename Collection::const_iterator it = collection.find(key);
+  if (it == collection.end()) {
+    return 0;
+  }
+  return it->second;
+}
+
+// Change the value associated with a particular key in a map or hash_map.
+// If the key is not present in the map the key and value are inserted,
+// otherwise the value is updated to be a copy of the value provided.
+// True indicates that an insert took place, false indicates an update.
+template <class Collection, class Key, class Value>
+bool InsertOrUpdate(Collection * const collection,
+                   const Key& key, const Value& value) {
+  pair<typename Collection::iterator, bool> ret =
+    collection->insert(typename Collection::value_type(key, value));
+  if (!ret.second) {
+    // update
+    ret.first->second = value;
+    return false;
+  }
+  return true;
+}
+
+// Insert a new key and value into a map or hash_map.
+// If the key is not present in the map the key and value are
+// inserted, otherwise nothing happens. True indicates that an insert
+// took place, false indicates the key was already present.
+template <class Collection, class Key, class Value>
+bool InsertIfNotPresent(Collection * const collection,
+                        const Key& key, const Value& value) {
+  pair<typename Collection::iterator, bool> ret =
+    collection->insert(typename Collection::value_type(key, value));
+  return ret.second;
+}
+
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // GOOGLE_PROTOBUF_STUBS_MAP_UTIL_H__