Detecting and fixing stringprintf.h format bugs

base/strings/stringprintf.h

Index: base/strings/stringprintf.h
diff --git a/base/strings/stringprintf.h b/base/strings/stringprintf.h
index 523f7ee55bf3693895b2d2d43d73f1c50565cb12..9ea4ce51f97106d1eb33c1b0100d5ec408ae9fff 100644
--- a/base/strings/stringprintf.h
+++ b/base/strings/stringprintf.h
@@ -7,6 +7,13 @@
 
 #include <stdarg.h>   // va_list
 
+#ifdef _MSC_VER

[Lei Zhang, 2015/09/29 03:16:17]

Check against COMPILER_MSVC instead? This is something clang+windows does not
have?

[brucedawson, 2015/09/29 21:39:39]

I'm not sure what the best check is. The need for the check is because nacl
builds cannot include sal.h. It doesn't necessarily matter whether the compiler
*understands* sal.h, it just has to be able to find it.

A nacl check seems ideal, but _MSC_VER or COMPILER_MSVC should work.

[Lei Zhang, 2015/09/29 21:42:37]

There's no hard rule, but in non-third-party code, COMPILER_MSVC usage
outnumbers _MSC_VER 2:1.

+// For _Printf_format_string_
+#include <sal.h>
+#else
+// For nacl builds
+#define _Printf_format_string_
+#endif
 #include <string>
 
 #include "base/base_export.h"
@@ -15,11 +22,13 @@
 namespace base {
 
 // Return a C++ string given printf-like input.
-BASE_EXPORT std::string StringPrintf(const char* format, ...)
+BASE_EXPORT std::string StringPrintf(_Printf_format_string_ const char* format,
+                                     ...)
     PRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #if defined(OS_WIN)
-BASE_EXPORT std::wstring StringPrintf(const wchar_t* format, ...)
-    WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
+BASE_EXPORT std::wstring StringPrintf(
+    _Printf_format_string_ const wchar_t* format,
+    ...) WPRINTF_FORMAT(1, 2) WARN_UNUSED_RESULT;
 #endif
 
 // Return a C++ string given vprintf-like input.
@@ -27,21 +36,25 @@ BASE_EXPORT std::string StringPrintV(const char* format, va_list ap)
     PRINTF_FORMAT(1, 0) WARN_UNUSED_RESULT;
 
 // Store result into a supplied string and return it.
-BASE_EXPORT const std::string& SStringPrintf(std::string* dst,
-                                             const char* format, ...)
-    PRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::string& SStringPrintf(
+    std::string* dst,
+    _Printf_format_string_ const char* format,
+    ...) PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT const std::wstring& SStringPrintf(std::wstring* dst,
-                                              const wchar_t* format, ...)
-    WPRINTF_FORMAT(2, 3);
+BASE_EXPORT const std::wstring& SStringPrintf(
+    std::wstring* dst,
+    _Printf_format_string_ const wchar_t* format,
+    ...) WPRINTF_FORMAT(2, 3);
 #endif
 
 // Append result to a supplied string.
-BASE_EXPORT void StringAppendF(std::string* dst, const char* format, ...)
-    PRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::string* dst,
+                               _Printf_format_string_ const char* format,
+                               ...) PRINTF_FORMAT(2, 3);
 #if defined(OS_WIN)
-BASE_EXPORT void StringAppendF(std::wstring* dst, const wchar_t* format, ...)
-    WPRINTF_FORMAT(2, 3);
+BASE_EXPORT void StringAppendF(std::wstring* dst,
+                               _Printf_format_string_ const wchar_t* format,
+                               ...) WPRINTF_FORMAT(2, 3);
 #endif
 
 // Lower-level routine that takes a va_list and appends to a specified