Moving away from shell api to support long path names on windows for filesystem.

base/file_path.cc

Index: base/file_path.cc
===================================================================
--- base/file_path.cc	(revision 69859)
+++ base/file_path.cc	(working copy)
@@ -34,6 +34,19 @@
 const FilePath::CharType FilePath::kCurrentDirectory[] = FILE_PATH_LITERAL(".");
 const FilePath::CharType FilePath::kParentDirectory[] = FILE_PATH_LITERAL("..");
 
+#if defined(OS_WIN)
+const FilePath::CharType FilePath::kExtendedPathPrefix[] =
+    FILE_PATH_LITERAL("\\\\?\\");
+
+const FilePath::CharType FilePath::kUNCExtendedPathPrefix[] =
+    FILE_PATH_LITERAL("\\\\?\\UNC\\");
+
+const FilePath::CharType FilePath::kSharePrefix[] =
+    FILE_PATH_LITERAL("\\\\");
+
+const int kSharePrefixLength = 2;
+#endif
+
 const FilePath::CharType FilePath::kExtensionSeparator = FILE_PATH_LITERAL('.');
 
 typedef FilePath::StringType StringType;
@@ -1190,3 +1203,51 @@
   return FilePath(copy);
 }
 #endif
+
+#if defined(OS_WIN)
+// TODO(kkanetkar): Taken from gears. Replace this when
+// crbug.com/67384 is addressed.
+StringType FilePath::ToLongFileNameHack(const StringType& path) const {
+  StringType long_path;
+  // This cast is for countering the compiler warning.
+  DWORD length_to_try = static_cast<DWORD>(path.length() * 2);
+  long_path.resize(length_to_try);
+  DWORD actual_length = GetLongPathName(path.c_str(),
+                                        &long_path.at(0),
+                                        length_to_try);
+  if (actual_length == 0) {
+    return path;
+  } else if (actual_length <= length_to_try) {
+    long_path.resize(actual_length);
+    return long_path;
+  }
+
+  length_to_try = actual_length;
+  long_path.resize(length_to_try);
+  actual_length = GetLongPathName(path.c_str(),
+                                  &long_path.at(0),
+                                  length_to_try + 1);
+  if (actual_length > 0 && actual_length <= length_to_try) {
+    long_path.resize(actual_length);
+    return long_path;
+  } else {
+    return path;
+  }
+}
+
+FilePath FilePath::GetLongPathHack() const {
+  if (StartsWith(path_, kExtendedPathPrefix, false) ||
+      StartsWith(path_, kUNCExtendedPathPrefix, false)) {
+    return FilePath(path_);
+  }
+
+  // Note that the 8.3 short file name can not be simply prefixed with the long
+  // path prefix. It has to be converted to long file name first.
+  if (StartsWith(path_, kSharePrefix, false)) {
+    return FilePath(kUNCExtendedPathPrefix + ToLongFileNameHack(
+        path_.substr(kSharePrefixLength)));
+  } else {
+    return FilePath(kExtendedPathPrefix + ToLongFileNameHack(path_));
+  }
+}
+#endif