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authorGravatar Abseil Team <absl-team@google.com>2020-01-09 09:58:48 -0800
committerGravatar Derek Mauro <dmauro@google.com>2020-01-09 14:19:30 -0500
commitb3aaac8a37c467a1125c794196caa90d0957bdc3 (patch)
tree054402e6c20470cf6d4150e58cf194737e122f3a /absl/base
parent63ee2f8877915a3565c29707dba8fe4d7822596a (diff)
Export of internal Abseil changes
-- 9beb68204986a015c9cb065b9fae4f9a8879a788 by Abseil Team <absl-team@google.com>: Move Base64EscapeInternal and CalculateBase64EscapedLenInternal to an internal header. PiperOrigin-RevId: 288917378 -- 90acfbe03b3f9f6de3ffa49c39343dfaa2c5d38c by Greg Falcon <gfalcon@google.com>: Update macos CI script to support the ALTERNATE_OPTIONS environment variable. PiperOrigin-RevId: 288913564 -- f1572e870678cdcda6b48cb39780d1ad984e4c1b by Derek Mauro <dmauro@google.com>: Makes absl::NullSafeStringView constexpr Fixes https://github.com/abseil/abseil-cpp/issues/583 PiperOrigin-RevId: 288906940 -- d28a8471e32c10caa64bfffe6d6d4d0a8d144013 by Abseil Team <absl-team@google.com>: absl::GetFlag is lock free for small trivially copyable types. PiperOrigin-RevId: 288768172 -- 2643b8ed1a1dc836b38ab9e46538a1af129ffd67 by Gennadiy Rozental <rogeeff@google.com>: Eliminate call to callback from flag initialization. We do not need to have this invocation inside FlagImpl::Init since SetCallback performs invocation anyways. Calling InitCallback from inside of Init complicates separation of value initialization from data guard initialization, which is about to happen. PiperOrigin-RevId: 288732526 -- 22caa880b7a4cb6da34e16a2e064a473c99e880b by Abseil Team <absl-team@google.com>: Fix the documentation on how to create a null string_view. PiperOrigin-RevId: 288727968 -- 10727c5cadc561837141176f4c9b9717cec9233a by Greg Falcon <gfalcon@google.com>: Change CI scripts for gcc to use the ALTERNATE_OPTIONS file as well. PiperOrigin-RevId: 288718855 -- 5d1e2dd6c7fb12af8aa4337a0f61872f5f0c5992 by Greg Falcon <gfalcon@google.com>: Add an option for using inline namespaces in Abseil. PiperOrigin-RevId: 288614491 GitOrigin-RevId: 9beb68204986a015c9cb065b9fae4f9a8879a788 Change-Id: If9acd46301e3df8cb231b4c16f7ed651bf4fb3c3
Diffstat (limited to 'absl/base')
-rw-r--r--absl/base/config.h34
-rw-r--r--absl/base/options.h26
2 files changed, 60 insertions, 0 deletions
diff --git a/absl/base/config.h b/absl/base/config.h
index 87f5b4ae..edbf2246 100644
--- a/absl/base/config.h
+++ b/absl/base/config.h
@@ -90,8 +90,42 @@
// not support forward declarations of its own types, nor does it support
// user-provided specialization of Abseil templates. Code that violates these
// rules may be broken without warning.)
+#if !defined(ABSL_OPTION_USE_INLINE_NAMESPACE) || \
+ !defined(ABSL_OPTION_INLINE_NAMESPACE_NAME)
+#error options.h is misconfigured.
+#endif
+
+// Check that ABSL_OPTION_INLINE_NAMESPACE_NAME is neither "head" nor ""
+#if defined(__cplusplus) && ABSL_OPTION_USE_INLINE_NAMESPACE == 1
+
+#define ABSL_INTERNAL_DO_TOKEN_STR(x) #x
+#define ABSL_INTERNAL_TOKEN_STR(x) ABSL_INTERNAL_DO_TOKEN_STR(x)
+#define ABSL_INTERNAL_INLINE_NAMESPACE_STR \
+ ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME)
+
+static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != '\0',
+ "options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must "
+ "not be empty.");
+static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
+ ABSL_INTERNAL_INLINE_NAMESPACE_STR[1] != 'e' ||
+ ABSL_INTERNAL_INLINE_NAMESPACE_STR[2] != 'a' ||
+ ABSL_INTERNAL_INLINE_NAMESPACE_STR[3] != 'd' ||
+ ABSL_INTERNAL_INLINE_NAMESPACE_STR[4] != '\0',
+ "options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must "
+ "be changed to a new, unique identifier name.");
+
+#endif
+
+#if ABSL_OPTION_USE_INLINE_NAMESPACE == 0
#define ABSL_NAMESPACE_BEGIN
#define ABSL_NAMESPACE_END
+#elif ABSL_OPTION_USE_INLINE_NAMESPACE == 1
+#define ABSL_NAMESPACE_BEGIN \
+ inline namespace ABSL_OPTION_INLINE_NAMESPACE_NAME {
+#define ABSL_NAMESPACE_END }
+#else
+#error options.h is misconfigured.
+#endif
// -----------------------------------------------------------------------------
// Compiler Feature Checks
diff --git a/absl/base/options.h b/absl/base/options.h
index 3961e63f..592b33b7 100644
--- a/absl/base/options.h
+++ b/absl/base/options.h
@@ -185,4 +185,30 @@
#define ABSL_OPTION_USE_STD_VARIANT 2
+
+// ABSL_OPTION_USE_INLINE_NAMESPACE
+// ABSL_OPTION_INLINE_NAMESPACE_NAME
+//
+// These options controls whether all entities in the absl namespace are
+// contained within an inner inline namespace. This does not affect the
+// user-visible API of Abseil, but it changes the mangled names of all symbols.
+//
+// This can be useful as a version tag if you are distributing Abseil in
+// precompiled form. This will prevent a binary library build of Abseil with
+// one inline namespace being used with headers configured with a different
+// inline namespace name. Binary packagers are reminded that Abseil does not
+// guarantee any ABI stability in Abseil, so any update of Abseil or
+// configuration change in such a binary package should be combined with a
+// new, unique value for the inline namespace name.
+//
+// A value of 0 means not to use inline namespaces.
+//
+// A value of 1 means to use an inline namespace with the given name inside
+// namespace absl. If this is set, ABSL_OPTION_INLINE_NAMESPACE_NAME must also
+// be changed to a new, unique identifier name. In particular "head" is not
+// allowed.
+
+#define ABSL_OPTION_USE_INLINE_NAMESPACE 0
+#define ABSL_OPTION_INLINE_NAMESPACE_NAME head
+
#endif // ABSL_BASE_OPTIONS_H_