Upstream android string implementation etc.

base/hash_tables.h

 // Copyright (c) 2011 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.
 //
 
 //
 // Deal with the differences between Microsoft and GNU implemenations
 // of hash_map. Allows all platforms to use |base::hash_map| and
 // |base::hash_set|.
 //  eg:
@@ skipping 16 matching lines @@
 #include "base/string16.h"
 
 #if defined(COMPILER_MSVC)
 #include <hash_map>
 #include <hash_set>
 namespace base {
 using stdext::hash_map;
 using stdext::hash_set;
 }
 #elif defined(COMPILER_GCC)
+#if defined(OS_ANDROID)
+#define HASH_NAMESPACE std

[darin (slow to review), 2011/06/24 16:46:05]

since this is a global #define, you should probably prefix it with BASE_.  that
way, you decrease chances of collisions with consumers.

also, it might be good to define this on all platforms to minimize the chances
of someone expecting it to be there on windows, but then finding out only after
submitting a try job that it is not.

again, since you are adding a new global #define, it is good to be careful.

[michaelbai, 2011/06/24 18:51:30]

Done.

+#else
+#define HASH_NAMESPACE __gnu_cxx
+#endif
+
 // This is a hack to disable the gcc 4.4 warning about hash_map and hash_set
 // being deprecated.  We can get rid of this when we upgrade to VS2008 and we
 // can use <tr1/unordered_map> and <tr1/unordered_set>.
 #ifdef __DEPRECATED
 #define CHROME_OLD__DEPRECATED __DEPRECATED
 #undef __DEPRECATED
 #endif
 
+#if defined(OS_ANDROID)
+#include <hash_map>
+#include <hash_set>
+#else
 #include <ext/hash_map>
 #include <ext/hash_set>
+#endif
+
 #include <string>
 
 #ifdef CHROME_OLD__DEPRECATED
 #define __DEPRECATED CHROME_OLD__DEPRECATED
 #undef CHROME_OLD__DEPRECATED
 #endif
 
 namespace base {
-using __gnu_cxx::hash_map;
-using __gnu_cxx::hash_set;
+using HASH_NAMESPACE::hash_map;
+using HASH_NAMESPACE::hash_set;
 }  // namespace base
 
-namespace __gnu_cxx {
+namespace HASH_NAMESPACE {
 
+#if !defined(OS_ANDROID)
 // The GNU C++ library provides identity hash functions for many integral types,
 // but not for |long long|.  This hash function will truncate if |size_t| is
 // narrower than |long long|.  This is probably good enough for what we will
 // use it for.
 
 #define DEFINE_TRIVIAL_HASH(integral_type) \
     template<> \
     struct hash<integral_type> { \
       std::size_t operator()(integral_type value) const { \
         return static_cast<std::size_t>(value); \
       } \
     }
 
 DEFINE_TRIVIAL_HASH(long long);
 DEFINE_TRIVIAL_HASH(unsigned long long);
 
 #undef DEFINE_TRIVIAL_HASH
+#endif  // !defined(OS_ANDROID)
 
 // Implement string hash functions so that strings of various flavors can
 // be used as keys in STL maps and sets.  The hash algorithm comes from the
 // GNU C++ library, in <tr1/functional>.  It is duplicated here because GCC
 // versions prior to 4.3.2 are unable to compile <tr1/functional> when RTTI
 // is disabled, as it is in our build.
 
 #define DEFINE_STRING_HASH(string_type) \
     template<> \
     struct hash<string_type> { \
       std::size_t operator()(const string_type& s) const { \
         std::size_t result = 0; \
         for (string_type::const_iterator i = s.begin(); i != s.end(); ++i) \
           result = (result * 131) + *i; \
         return result; \
       } \
     }
 
 DEFINE_STRING_HASH(std::string);
 DEFINE_STRING_HASH(string16);
 
 #undef DEFINE_STRING_HASH
 
-}  // namespace __gnu_cxx
+}  // namespace HASH_NAMESPACE
 
 #endif  // COMPILER
 
 #endif  // BASE_HASH_TABLES_H_