Adds AppendASCII which will append an ASCII path component.

Since this is safe to do on all platform path encodings (even Linux), this allows path components to be taken from ASCII sources without #ifdefs for the caller.

Review URL: http://codereview.chromium.org/18134

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8394 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 29 insertions, 1 deletions

diff --git a/base/file_path.cc b/base/file_path.cc
index 3375b66..406d018 100644
--- a/base/file_path.cc
+++ b/base/file_path.cc
@@ -252,6 +252,15 @@ FilePath FilePath::Append(const FilePath& component) const {
   return Append(component.value());
 }
 
+FilePath FilePath::AppendASCII(const std::string& component) const {
+  DCHECK(IsStringASCII(component));
+#if defined(OS_WIN)
+  return Append(ASCIIToWide(component));
+#elif defined(OS_POSIX)
+  return Append(component);
+#endif
+}
+
 bool FilePath::IsAbsolute() const {
   return IsPathAbsolute(path_);
 }
diff --git a/base/file_path.h b/base/file_path.h
index d82f8f4..053b815b 100644
--- a/base/file_path.h
+++ b/base/file_path.h
@@ -189,6 +189,14 @@ class FilePath {
   FilePath Append(const StringType& component) const WARN_UNUSED_RESULT;
   FilePath Append(const FilePath& component) const WARN_UNUSED_RESULT;
 
+  // Although Windows StringType is std::wstring, since the encoding it uses for
+  // paths is well defined, it can handle ASCII path components as well.
+  // Mac uses UTF8, and since ASCII is a subset of that, it works there as well.
+  // 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;
+
   // Returns true if this FilePath contains an absolute path.  On Windows, an
   // absolute path begins with either a drive letter specification followed by
   // a separator character, or with two separator characters.  On POSIX
diff --git a/base/file_path_unittest.cc b/base/file_path_unittest.cc
index b237af6..3439c6c 100644
--- a/base/file_path_unittest.cc
+++ b/base/file_path_unittest.cc
@@ -5,7 +5,7 @@
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
-#include "base/path_service.h"
+#include "base/string_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
@@ -293,6 +293,17 @@ TEST_F(FilePathTest, Append) {
     FilePath observed_path = root.Append(FilePath(leaf));
     EXPECT_EQ(FilePath::StringType(cases[i].expected), observed_path.value()) <<
               "i: " << i << ", root: " << root.value() << ", leaf: " << leaf;
+
+    // TODO(erikkay): It would be nice to have a unicode test append value to
+    // handle the case when AppendASCII is passed UTF8
+#if defined(OS_WIN)
+    std::string ascii = WideToASCII(leaf);
+#elif defined(OS_POSIX)
+    std::string ascii = leaf;
+#endif
+    observed_str = root.AppendASCII(ascii);
+    EXPECT_EQ(FilePath::StringType(cases[i].expected), observed_str.value()) <<
+              "i: " << i << ", root: " << root.value() << ", leaf: " << leaf;
   }
 }