Fix NSString conversions to treat a null NSString as a string of length 0, instead of crashing. This allows Cocoa to use null objects as empties, as is its wont, and we only run a check when needed.

This CL also removes the now-superfluous checks for null NSStrings from BugReportWindowController.  A cursory look through the code shows that there are many places where a check for null precedes a call to an NSString conversion; filed another bug against myself to go through and fix all of these (http://code.google.com/p/chromium/issues/detail?id=27055).  Also filed a bug to expand unit tests for NSString conversion methods (http://code.google.com/p/chromium/issues/detail?id=27059).


Review URL: http://codereview.chromium.org/371057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31408 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 28 insertions, 1 deletions

diff --git a/base/base.gyp b/base/base.gyp
index f09e2e5..31d9d49 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -621,6 +621,7 @@
         'string_tokenizer_unittest.cc',
         'string_util_unittest.cc',
         'sys_info_unittest.cc',
+        'sys_string_conversions_mac_unittest.mm',
         'sys_string_conversions_unittest.cc',
         'system_monitor_unittest.cc',
         'task_unittest.cc',
diff --git a/base/sys_string_conversions.h b/base/sys_string_conversions.h
index 18be826..edf4dd2 100644
--- a/base/sys_string_conversions.h
+++ b/base/sys_string_conversions.h
@@ -71,7 +71,8 @@ std::string SysCFStringRefToUTF8(CFStringRef ref);
 string16 SysCFStringRefToUTF16(CFStringRef ref);
 std::wstring SysCFStringRefToWide(CFStringRef ref);
 
-// Same, but accepts NSString input.
+// Same, but accepts NSString input. Converts nil NSString* to the appropriate
+// string type of length 0.
 std::string SysNSStringToUTF8(NSString* ref);
 string16 SysNSStringToUTF16(NSString* ref);
 std::wstring SysNSStringToWide(NSString* ref);
diff --git a/base/sys_string_conversions_mac.mm b/base/sys_string_conversions_mac.mm
index d0b2b235c..9b9a07e 100644
--- a/base/sys_string_conversions_mac.mm
+++ b/base/sys_string_conversions_mac.mm
@@ -184,14 +184,20 @@ std::wstring SysCFStringRefToWide(CFStringRef ref) {
 }
 
 std::string SysNSStringToUTF8(NSString* nsstring) {
+  if (!nsstring)
+    return std::string();
   return SysCFStringRefToUTF8(reinterpret_cast<CFStringRef>(nsstring));
 }
 
 string16 SysNSStringToUTF16(NSString* nsstring) {
+  if (!nsstring)
+    return string16();
   return SysCFStringRefToUTF16(reinterpret_cast<CFStringRef>(nsstring));
 }
 
 std::wstring SysNSStringToWide(NSString* nsstring) {
+  if (!nsstring)
+    return std::wstring();
   return SysCFStringRefToWide(reinterpret_cast<CFStringRef>(nsstring));
 }
 
diff --git a/base/sys_string_conversions_mac_unittest.mm b/base/sys_string_conversions_mac_unittest.mm
new file mode 100644
index 0000000..628b515
--- /dev/null
+++ b/base/sys_string_conversions_mac_unittest.mm
@@ -0,0 +1,19 @@
+// Copyright (c) 2009 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.
+
+#import <Foundation/Foundation.h>
+
+#include "base/string16.h"
+#include "base/sys_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+TEST(SysStrings, ConversionsFromNSString) {
+  EXPECT_STREQ("Hello, world!",
+               base::SysNSStringToUTF8(@"Hello, world!").c_str());
+
+  // Conversions should be able to handle a NULL value without crashing.
+  EXPECT_STREQ("", base::SysNSStringToUTF8(nil).c_str());
+  EXPECT_EQ(string16(), base::SysNSStringToUTF16(nil));
+  EXPECT_STREQ(L"", base::SysNSStringToWide(nil).c_str());
+}