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authorAllan Sandfeld Jensen <allan.jensen@theqtcompany.com>2016-01-25 11:39:07 +0100
committerOswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>2016-01-25 15:20:42 +0000
commit6c91641271e536ffaa88a1dff5127e42ee99a91e (patch)
tree703d9dd49602377ddc90cbf886aad37913f2496b /chromium/build/buildflag.h
parentb145b7fafd36f0c260d6a768c81fc14e32578099 (diff)
downloadqtwebengine-chromium-6c91641271e536ffaa88a1dff5127e42ee99a91e.tar.gz
BASELINE: Update Chromium to 49.0.2623.23
Also adds missing printing sources. Change-Id: I3726b8f0c7d6751c9fc846096c571fadca7108cd Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Diffstat (limited to 'chromium/build/buildflag.h')
-rw-r--r--chromium/build/buildflag.h47
1 files changed, 47 insertions, 0 deletions
diff --git a/chromium/build/buildflag.h b/chromium/build/buildflag.h
new file mode 100644
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+++ b/chromium/build/buildflag.h
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+// 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.
+
+#ifndef BUILD_BUILDFLAG_H_
+#define BUILD_BUILDFLAG_H_
+
+// These macros un-mangle the names of the build flags in a way that looks
+// natural, and gives errors if the flag is not defined. Normally in the
+// preprocessor it's easy to make mistakes that interpret "you haven't done
+// the setup to know what the flag is" as "flag is off". Normally you would
+// include the generated header rather than include this file directly.
+//
+// This is for use with generated headers. See build/build_header.gni.
+
+// This dance of two macros does a concatenation of two preprocessor args using
+// ## doubly indirectly because using ## directly prevents macros in that
+// parameter from being expanded.
+#define BUILDFLAG_CAT_INDIRECT(a, b) a ## b
+#define BUILDFLAG_CAT(a, b) BUILDFLAG_CAT_INDIRECT(a, b)
+
+// Accessor for build flags.
+//
+// To test for a value, if the build file specifies:
+//
+// ENABLE_FOO=true
+//
+// Then you would check at build-time in source code with:
+//
+// #include "foo_flags.h" // The header the build file specified.
+//
+// #if BUILDFLAG(ENABLE_FOO)
+// ...
+// #endif
+//
+// There will no #define called ENABLE_FOO so if you accidentally test for
+// whether that is defined, it will always be negative. You can also use
+// the value in expressions:
+//
+// const char kSpamServerName[] = BUILDFLAG(SPAM_SERVER_NAME);
+//
+// Because the flag is accessed as a preprocessor macro with (), an error
+// will be thrown if the proper header defining the internal flag value has
+// not been included.
+#define BUILDFLAG(flag) (BUILDFLAG_CAT(BUILDFLAG_INTERNAL_, flag)())
+
+#endif // BUILD_BUILDFLAG_H_