Add GetWellKnowMimeTypeFromExtension() to limit the search to a fixed set of well-known types without consulting the OS/registry.

BUG=86108
TESTS=none
Review URL: http://codereview.chromium.org/7204036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@89773 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 39 insertions, 9 deletions

diff --git a/net/base/mime_util.cc b/net/base/mime_util.cc
index 05c04ca..75572a9 100644
--- a/net/base/mime_util.cc
+++ b/net/base/mime_util.cc
@@ -28,6 +28,9 @@ class MimeUtil : public PlatformMimeUtil {
   bool GetMimeTypeFromFile(const FilePath& file_path,
                            std::string* mime_type) const;
 
+  bool GetWellKnownMimeTypeFromExtension(const FilePath::StringType& ext,
+                                         std::string* mime_type) const;
+
   bool IsSupportedImageMimeType(const char* mime_type) const;
   bool IsSupportedMediaMimeType(const char* mime_type) const;
   bool IsSupportedNonImageMimeType(const char* mime_type) const;
@@ -59,6 +62,10 @@ class MimeUtil : public PlatformMimeUtil {
   // For faster lookup, keep hash sets.
   void InitializeMimeTypeMaps();
 
+  bool GetMimeTypeFromExtensionHelper(
+      const FilePath::StringType& ext, bool include_platform_types,
+      std::string* mime_type) const;
+
   typedef base::hash_set<std::string> MimeMappings;
   MimeMappings image_map_;
   MimeMappings media_map_;
@@ -146,6 +153,25 @@ static const char* FindMimeType(const MimeInfo* mappings,
 
 bool MimeUtil::GetMimeTypeFromExtension(const FilePath::StringType& ext,
                                         string* result) const {
+  return GetMimeTypeFromExtensionHelper(ext, true, result);
+}
+
+bool MimeUtil::GetWellKnownMimeTypeFromExtension(
+    const FilePath::StringType& ext, string* result) const {
+  return GetMimeTypeFromExtensionHelper(ext, false, result);
+}
+
+bool MimeUtil::GetMimeTypeFromFile(const FilePath& file_path,
+                                   string* result) const {
+  FilePath::StringType file_name_str = file_path.Extension();
+  if (file_name_str.empty())
+    return false;
+  return GetMimeTypeFromExtension(file_name_str.substr(1), result);
+}
+
+bool MimeUtil::GetMimeTypeFromExtensionHelper(
+    const FilePath::StringType& ext, bool include_platform_types,
+    string* result) const {
   // Avoids crash when unable to handle a long file path. See crbug.com/48733.
   const unsigned kMaxFilePathSize = 65536;
   if (ext.length() > kMaxFilePathSize)
@@ -171,7 +197,7 @@ bool MimeUtil::GetMimeTypeFromExtension(const FilePath::StringType& ext,
     return true;
   }
 
-  if (GetPlatformMimeTypeFromExtension(ext, result))
+  if (include_platform_types && GetPlatformMimeTypeFromExtension(ext, result))
     return true;
 
   mime_type = FindMimeType(secondary_mappings, arraysize(secondary_mappings),
@@ -184,14 +210,6 @@ bool MimeUtil::GetMimeTypeFromExtension(const FilePath::StringType& ext,
   return false;
 }
 
-bool MimeUtil::GetMimeTypeFromFile(const FilePath& file_path,
-                                   string* result) const {
-  FilePath::StringType file_name_str = file_path.Extension();
-  if (file_name_str.empty())
-    return false;
-  return GetMimeTypeFromExtension(file_name_str.substr(1), result);
-}
-
 // From WebKit's WebCore/platform/MIMETypeRegistry.cpp:
 
 static const char* const supported_image_types[] = {
@@ -486,6 +504,11 @@ bool GetMimeTypeFromFile(const FilePath& file_path, std::string* mime_type) {
   return g_mime_util.Get().GetMimeTypeFromFile(file_path, mime_type);
 }
 
+bool GetWellKnownMimeTypeFromExtension(const FilePath::StringType& ext,
+                                       std::string* mime_type) {
+  return g_mime_util.Get().GetWellKnownMimeTypeFromExtension(ext, mime_type);
+}
+
 bool GetPreferredExtensionForMimeType(const std::string& mime_type,
                                       FilePath::StringType* extension) {
   return g_mime_util.Get().GetPreferredExtensionForMimeType(mime_type,
diff --git a/net/base/mime_util.h b/net/base/mime_util.h
index d228b58..545abe0 100644
--- a/net/base/mime_util.h
+++ b/net/base/mime_util.h
@@ -19,6 +19,13 @@ namespace net {
 NET_API bool GetMimeTypeFromExtension(const FilePath::StringType& ext,
                                       std::string* mime_type);
 
+// Get the mime type (if any) that is associated with the given file extension.
+// Returns true if a corresponding mime type exists. In this method,
+// the search for a mime type is constrained to a limited set of
+// types known to the net library, the OS/registry is not consulted.
+NET_API bool GetWellKnownMimeTypeFromExtension(const FilePath::StringType& ext,
+                                               std::string* mime_type);
+
 // Get the mime type (if any) that is associated with the given file.  Returns
 // true if a corresponding mime type exists.
 NET_API bool GetMimeTypeFromFile(const FilePath& file_path,