From 19299904343daf191267564fe32e6cd5c165cd42 Mon Sep 17 00:00:00 2001
From: Chris Pearson <christopherx.c.pearson@intel.com>
Date: Wed, 2 Jun 2010 16:25:35 -0700
Subject: Fixed LOG_ASSERT() compilation errors in native debug builds.

Invoking LOG_ASSERT, LOG_ALWAYS_FATAL or LOG_ALWAYS_FATAL_IF variadic macros
without the printf format string arg caused compilation errors because the
variable arg list (__VA_ARGS__) was eventually passed to
__android_log_assert() func in place of a required parameter. This error
only occured in debug builds because LOG_ASSERT() is a no-op in release
builds.  This change allows debug builds to succeed.

Change-Id: I7e7b7de3e501133468ce083e0e0d6e699dd59667
Signed-off-by: Chris Pearson <christopherx.c.pearson@intel.com>
---
 include/cutils/log.h | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

(limited to 'include/cutils')

diff --git a/include/cutils/log.h b/include/cutils/log.h
index dd47c358..f6020170 100644
--- a/include/cutils/log.h
+++ b/include/cutils/log.h
@@ -291,11 +291,11 @@ extern "C" {
  */
 #define LOG_ALWAYS_FATAL_IF(cond, ...) \
     ( (CONDITION(cond)) \
-    ? ((void)android_printAssert(#cond, LOG_TAG, __VA_ARGS__)) \
+    ? ((void)android_printAssert(#cond, LOG_TAG, ## __VA_ARGS__)) \
     : (void)0 )
 
 #define LOG_ALWAYS_FATAL(...) \
-    ( ((void)android_printAssert(NULL, LOG_TAG, __VA_ARGS__)) )
+    ( ((void)android_printAssert(NULL, LOG_TAG, ## __VA_ARGS__)) )
 
 /*
  * Versions of LOG_ALWAYS_FATAL_IF and LOG_ALWAYS_FATAL that
@@ -308,7 +308,7 @@ extern "C" {
 
 #else
 
-#define LOG_FATAL_IF(cond, ...) LOG_ALWAYS_FATAL_IF(cond, __VA_ARGS__)
+#define LOG_FATAL_IF(cond, ...) LOG_ALWAYS_FATAL_IF(cond, ## __VA_ARGS__)
 #define LOG_FATAL(...) LOG_ALWAYS_FATAL(__VA_ARGS__)
 
 #endif
@@ -317,7 +317,7 @@ extern "C" {
  * Assertion that generates a log message when the assertion fails.
  * Stripped out of release builds.  Uses the current LOG_TAG.
  */
-#define LOG_ASSERT(cond, ...) LOG_FATAL_IF(!(cond), __VA_ARGS__)
+#define LOG_ASSERT(cond, ...) LOG_FATAL_IF(!(cond), ## __VA_ARGS__)
 //#define LOG_ASSERT(cond) LOG_FATAL_IF(!(cond), "Assertion failed: " #cond)
 
 // ---------------------------------------------------------------------
@@ -403,8 +403,24 @@ typedef enum {
 #define android_vprintLog(prio, cond, tag, fmt...) \
     __android_log_vprint(prio, tag, fmt)
 
+/* XXX Macros to work around syntax errors in places where format string
+ * arg is not passed to LOG_ASSERT, LOG_ALWAYS_FATAL or LOG_ALWAYS_FATAL_IF
+ * (happens only in debug builds).
+ */
+
+/* Returns 2nd arg.  Used to substitute default value if caller's vararg list
+ * is empty.
+ */
+#define __android_second(dummy, second, ...)     second
+
+/* If passed multiple args, returns ',' followed by all but 1st arg, otherwise
+ * returns nothing.
+ */
+#define __android_rest(first, ...)               , ## __VA_ARGS__
+
 #define android_printAssert(cond, tag, fmt...) \
-    __android_log_assert(cond, tag, fmt)
+    __android_log_assert(cond, tag, \
+        __android_second(0, ## fmt, NULL) __android_rest(fmt))
 
 #define android_writeLog(prio, tag, text) \
     __android_log_write(prio, tag, text)
@@ -413,7 +429,7 @@ typedef enum {
     __android_log_bwrite(tag, payload, len)
 #define android_btWriteLog(tag, type, payload, len) \
     __android_log_btwrite(tag, type, payload, len)
-	
+
 // TODO: remove these prototypes and their users
 #define android_testLog(prio, tag) (1)
 #define android_writevLog(vec,num) do{}while(0)
-- 
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