Move a few functions commonly called with char* to StringPiece.

In some cases this will avoid the implicit char* -> std::string conversion,
object creation, and string copying.  One of the biggest benefit is on Windows,
where we can save some conversions in FilePath::AppendASCII.

Review URL: http://codereview.chromium.org/113996


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17182 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 10 insertions, 9 deletions

diff --git a/base/file_path.cc b/base/file_path.cc
index b1bf687..a00659e 100644
--- a/base/file_path.cc
+++ b/base/file_path.cc
@@ -252,12 +252,12 @@ FilePath FilePath::Append(const FilePath& component) const {
   return Append(component.value());
 }
 
-FilePath FilePath::AppendASCII(const std::string& component) const {
+FilePath FilePath::AppendASCII(const StringPiece& component) const {
   DCHECK(IsStringASCII(component));
 #if defined(OS_WIN)
   return Append(ASCIIToWide(component));
 #elif defined(OS_POSIX)
-  return Append(component);
+  return Append(component.as_string());
 #endif
 }
 
diff --git a/base/file_path.h b/base/file_path.h
index d4f35d1..73de4a6 100644
--- a/base/file_path.h
+++ b/base/file_path.h
@@ -70,6 +70,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/hash_tables.h"
+#include "base/string_piece.h"  // For implicit conversions.
 
 // Windows-style drive letter support and pathname separator characters can be
 // enabled and disabled independently, to aid testing.  These #defines are
@@ -199,7 +200,7 @@ class FilePath {
   // On Linux, although it can use any 8-bit encoding for paths, we assume that
   // ASCII is a valid subset, regardless of the encoding, since many operating
   // system paths will always be ASCII.
-  FilePath AppendASCII(const std::string& component) const WARN_UNUSED_RESULT;
+  FilePath AppendASCII(const StringPiece& component) const WARN_UNUSED_RESULT;
 
   // Returns true if this FilePath contains an absolute path.  On Windows, an
   // absolute path begins with either a drive letter specification followed by
diff --git a/base/string_util.cc b/base/string_util.cc
index c666960..1cdbd7b 100644
--- a/base/string_util.cc
+++ b/base/string_util.cc
@@ -466,7 +466,7 @@ std::string WideToASCII(const std::wstring& wide) {
   return std::string(wide.begin(), wide.end());
 }
 
-std::wstring ASCIIToWide(const std::string& ascii) {
+std::wstring ASCIIToWide(const StringPiece& ascii) {
   DCHECK(IsStringASCII(ascii));
   return std::wstring(ascii.begin(), ascii.end());
 }
@@ -476,7 +476,7 @@ std::string UTF16ToASCII(const string16& utf16) {
   return std::string(utf16.begin(), utf16.end());
 }
 
-string16 ASCIIToUTF16(const std::string& ascii) {
+string16 ASCIIToUTF16(const StringPiece& ascii) {
   DCHECK(IsStringASCII(ascii));
   return string16(ascii.begin(), ascii.end());
 }
@@ -523,7 +523,7 @@ bool IsStringASCII(const string16& str) {
 }
 #endif
 
-bool IsStringASCII(const std::string& str) {
+bool IsStringASCII(const StringPiece& str) {
   return DoIsStringASCII(str);
 }
 
diff --git a/base/string_util.h b/base/string_util.h
index f40cc8d..b082078 100644
--- a/base/string_util.h
+++ b/base/string_util.h
@@ -174,9 +174,9 @@ std::wstring CollapseWhitespace(const std::wstring& text,
 
 // These convert between ASCII (7-bit) and Wide/UTF16 strings.
 std::string WideToASCII(const std::wstring& wide);
-std::wstring ASCIIToWide(const std::string& ascii);
+std::wstring ASCIIToWide(const StringPiece& ascii);
 std::string UTF16ToASCII(const string16& utf16);
-string16 ASCIIToUTF16(const std::string& ascii);
+string16 ASCIIToUTF16(const StringPiece& ascii);
 
 // These convert between UTF-8, -16, and -32 strings. They are potentially slow,
 // so avoid unnecessary conversions. The low-level versions return a boolean
@@ -252,7 +252,7 @@ bool IsString8Bit(const std::wstring& str);
 bool IsStringUTF8(const std::string& str);
 bool IsStringWideUTF8(const std::wstring& str);
 bool IsStringASCII(const std::wstring& str);
-bool IsStringASCII(const std::string& str);
+bool IsStringASCII(const StringPiece& str);
 bool IsStringASCII(const string16& str);
 
 // ASCII-specific tolower.  The standard library's tolower is locale sensitive,