Enforce lowercase switches when calling CommandLine::HasSwitch(const char*).

base/command_line.cc

Index: base/command_line.cc
diff --git a/base/command_line.cc b/base/command_line.cc
index 3e143cc5d449f358936726f33c8d3fda95064f03..136a8b34ffb744e24416bb72953c79f83345d06b 100644
--- a/base/command_line.cc
+++ b/base/command_line.cc
@@ -93,6 +93,14 @@ void AppendSwitchesAndArguments(CommandLine* command_line,
   }
 }
 
+bool ContainsUpperASCII(const char* string) {
+  for (; *string; ++string) {
+    if (*string >= 'A' && *string <= 'Z')
+      return true;
+  }
+  return false;
+}
+
 // Lowercase switches for backwards compatiblity *on Windows*.
 #if defined(OS_WIN)
 std::string LowerASCIIOnWindows(const std::string& string) {
@@ -263,11 +271,18 @@ void CommandLine::SetProgram(const FilePath& program) {
 }
 
 bool CommandLine::HasSwitch(const std::string& switch_string) const {

[tapted, 2015/04/02 01:46:14]

How many times is the std::string version called now? Maybe it's not worth
changing this fn.

[jackhou1, 2015/04/02 04:51:51]

Agreed. 1% of calls.

-  return switches_.find(LowerASCIIOnWindows(switch_string)) != switches_.end();
+#if defined(OS_WIN)
+  if (ContainsUpperASCII(switch_string.c_str()))
+    return switches_.find(LowerASCIIOnWindows(switch_string)) !=
+           switches_.end();
+#endif
+
+  return switches_.find(switch_string) != switches_.end();
 }
 
 bool CommandLine::HasSwitch(const char string_constant[]) const {
-  return HasSwitch(std::string(string_constant));
+  DCHECK(!ContainsUpperASCII(string_constant));

[tapted, 2015/04/02 01:46:14]

I think we can avoid the extra function with something like

DCHECK_EQ(StringToLowerASCII(string_constant), string_constant);

[jackhou1, 2015/04/02 04:51:51]

Done.

+  return switches_.find(std::string(string_constant)) != switches_.end();

[tapted, 2015/04/02 01:46:15]

is the std::string(..) still needed?

[jackhou1, 2015/04/02 04:51:51]

Nope, but the one in the DEBUG_EQ is.

 }
 
 std::string CommandLine::GetSwitchValueASCII(
@@ -291,8 +306,15 @@ FilePath CommandLine::GetSwitchValuePath(
 
 CommandLine::StringType CommandLine::GetSwitchValueNative(
     const std::string& switch_string) const {
-  SwitchMap::const_iterator result =
-    switches_.find(LowerASCIIOnWindows(switch_string));
+#if defined(OS_WIN)

[tapted, 2015/04/02 01:46:14]

I think we should defer this until there's a char[] overload of this function
and we have baseline on that

[jackhou1, 2015/04/02 04:51:51]

This method is about 9% of lookups during startup, but yeah, there's probably
more to gain by adding a char[] overload.

+  if (ContainsUpperASCII(switch_string.c_str())) {
+    SwitchMap::const_iterator result =
+        switches_.find(LowerASCIIOnWindows(switch_string));
+    return result == switches_.end() ? StringType() : result->second;
+  }
+#endif
+
+  SwitchMap::const_iterator result = switches_.find(switch_string);
   return result == switches_.end() ? StringType() : result->second;
 }