base: Disallow mixing NDEBUG settings in logging.{h,cc}.

I am concerned about the possibility that other users of the
files in Chrome's base/ directory (e.g. Chrome OS) may build
a library from these files with NDEBUG defined and then link
it into a binary that includes the headers without defining
NDEBUG, or vice versa.

This change mangles InitLogging()'s name in logging.h based
on whether NDEBUG is defined so that linking will fail if
there's a mismatch (Evan provided useful advice here).

BUG=chromium-os:1124
TEST=built Debug and Release Chrome, built all Chrome OS packages, and then changed a Chrome OS package that links against libbase.a to define NDEBUG and checked that it failed to link

Review URL: http://codereview.chromium.org/3106032

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57098 0039d316-1c4b-4281-b951-d872f2087c98

base/logging.cc

@@ -82,10 +82,8 @@ const int kAlwaysPrintErrorLevel = LOG_ERROR;
 // will be lazily initialized to the default value when it is
 // first needed.
 #if defined(OS_WIN)
-typedef wchar_t PathChar;
 typedef std::wstring PathString;
 #else
-typedef char PathChar;
 typedef std::string PathString;
 #endif
 PathString* log_file_name = NULL;
@@ -248,8 +246,10 @@ void InitLogMutex() {
 #endif
 }
 
-void InitLogging(const PathChar* new_log_file, LoggingDestination logging_dest,
-                 LogLockingState lock_log, OldFileDeletionState delete_old) {
+void BaseInitLoggingImpl(const PathChar* new_log_file,
+                         LoggingDestination logging_dest,
+                         LogLockingState lock_log,
+                         OldFileDeletionState delete_old) {
   g_enable_dcheck =
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnableDCHECK);
 

base/logging.h

@@ -126,6 +126,31 @@ enum LogLockingState { LOCK_LOG_FILE, DONT_LOCK_LOG_FILE };
 // Defaults to APPEND_TO_OLD_LOG_FILE.
 enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE };
 
+// TODO(avi): do we want to do a unification of character types here?
+#if defined(OS_WIN)
+typedef wchar_t PathChar;
+#else
+typedef char PathChar;
+#endif
+
+// Define different names for the BaseInitLoggingImpl() function depending on
+// whether NDEBUG is defined or not so that we'll fail to link if someone tries
+// to compile logging.cc with NDEBUG but includes logging.h without defining it,
+// or vice versa.
+#if NDEBUG
+#define BaseInitLoggingImpl BaseInitLoggingImpl_built_with_NDEBUG
+#else
+#define BaseInitLoggingImpl BaseInitLoggingImpl_built_without_NDEBUG
+#endif
+
+// Implementation of the InitLogging() method declared below.  We use a
+// more-specific name so we can #define it above without affecting other code
+// that has named stuff "InitLogging".
+void BaseInitLoggingImpl(const PathChar* log_file,
+                         LoggingDestination logging_dest,
+                         LogLockingState lock_log,
+                         OldFileDeletionState delete_old);
+
 // Sets the log file name and other global logging state. Calling this function
 // is recommended, and is normally done at the beginning of application init.
 // If you don't call it, all the flags will be initialized to their default
@@ -136,14 +161,12 @@ enum OldFileDeletionState { DELETE_OLD_LOG_FILE, APPEND_TO_OLD_LOG_FILE };
 // The default log file is initialized to "debug.log" in the application
 // directory. You probably don't want this, especially since the program
 // directory may not be writable on an enduser's system.
-#if defined(OS_WIN)
-void InitLogging(const wchar_t* log_file, LoggingDestination logging_dest,
-                 LogLockingState lock_log, OldFileDeletionState delete_old);
-#elif defined(OS_POSIX)
-// TODO(avi): do we want to do a unification of character types here?
-void InitLogging(const char* log_file, LoggingDestination logging_dest,
-                 LogLockingState lock_log, OldFileDeletionState delete_old);
-#endif
+inline void InitLogging(const PathChar* log_file,
+                        LoggingDestination logging_dest,
+                        LogLockingState lock_log,
+                        OldFileDeletionState delete_old) {
+  BaseInitLoggingImpl(log_file, logging_dest, lock_log, delete_old);
+}
 
 // Sets the log level. Anything at or above this level will be written to the
 // log file/displayed to the user (if applicable). Anything below this level