Sniff MIME type for files which have unknown extensions.

chrome/browser/chromeos/extensions/file_manager/private_api_tasks.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/extensions/file_manager/private_api_tasks.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "chrome/browser/chromeos/drive/file_system_util.h"
-#include "chrome/browser/chromeos/file_manager/file_tasks.h"
 #include "chrome/browser/chromeos/file_manager/fileapi_util.h"
 #include "chrome/browser/chromeos/file_manager/mime_util.h"
 #include "chrome/browser/chromeos/fileapi/file_system_backend.h"
 #include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/filename_util.h"
+#include "net/base/mime_sniffer.h"
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_url.h"
 
+using content::BrowserThread;
+using extensions::app_file_handler_util::PathAndMimeTypeSet;
 using fileapi::FileSystemURL;
 
 namespace extensions {
 namespace {
 
 // Error messages.
 const char kInvalidFileUrl[] = "Invalid file URL";
 
 // Make a set of unique filename suffixes out of the list of file URLs.
 std::set<std::string> GetUniqueSuffixes(
@@ skipping 17 matching lines @@
   std::set<std::string> mime_types;
   for (size_t i = 0; i < mime_type_list.size(); ++i) {
     const std::string mime_type = mime_type_list[i];
     // We'll skip empty MIME types and existing MIME types.
     if (!mime_type.empty())
       mime_types.insert(mime_type);
   }
   return mime_types;
 }
 
+void SniffMimeType(PathAndMimeTypeSet* path_mime_set,
+                   std::vector<GURL>* file_urls) {
+  PathAndMimeTypeSet sniffed_path_mime_set;
+  std::vector<char> content(net::kMaxBytesToSniff);
+
+  // For each files, sniff its MIME type if it is empty
+  for (PathAndMimeTypeSet::iterator it = path_mime_set->begin();
+       it != path_mime_set->end();
+       ++it) {
+    const base::FilePath& file_path = it->first;
+    std::string mime_type = it->second;
+
+    // Note: sniff MIME type only for local files to avoid getting file's
+    // content via network frequently.

[hashimoto, 2014/04/10 11:54:21]

This comment is misleading as we can get MIME type of the file from the Drive
server so that there is no need to sniff Drive files (of course, its cost is
also the reason why we don't do it.)

[fukino, 2014/04/10 12:10:59]

Done.

+    if (mime_type.empty() && !drive::util::IsUnderDriveMountPoint(file_path)) {
+      int bytes_read = base::ReadFile(file_path, &content[0], content.size());
+      if (bytes_read >= 0) {
+        net::SniffMimeType(&content[0],
+                           bytes_read,
+                           net::FilePathToFileURL(file_path),
+                           std::string(),  // type_hint (passes no hint)
+                           &mime_type);
+      }
+    }
+    sniffed_path_mime_set.insert(std::make_pair(file_path, mime_type));
+  }
+  path_mime_set->swap(sniffed_path_mime_set);
+}
+
 }  // namespace
 
 bool FileBrowserPrivateExecuteTaskFunction::RunImpl() {
   using extensions::api::file_browser_private::ExecuteTask::Params;
   using extensions::api::file_browser_private::ExecuteTask::Results::Create;
   const scoped_ptr<Params> params(Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params);
 
   file_manager::file_tasks::TaskDescriptor task;
   if (!file_manager::file_tasks::ParseTaskID(params->task_id, &task)) {
@@ skipping 60 matching lines @@
   if (params->mime_types.size() != params->file_urls.size() &&
       params->mime_types.size() != 0)
     return false;
 
   const scoped_refptr<fileapi::FileSystemContext> file_system_context =
       file_manager::util::GetFileSystemContextForRenderViewHost(
           GetProfile(), render_view_host());
 
   // Collect all the URLs, convert them to GURLs, and crack all the urls into
   // file paths.
-  extensions::app_file_handler_util::PathAndMimeTypeSet path_mime_set;
-  std::vector<GURL> file_urls;
+  scoped_ptr<PathAndMimeTypeSet> path_mime_set(new PathAndMimeTypeSet);
+  scoped_ptr<std::vector<GURL> > file_urls(new std::vector<GURL>);
   for (size_t i = 0; i < params->file_urls.size(); ++i) {
     std::string mime_type;
     if (params->mime_types.size() != 0)
       mime_type = params->mime_types[i];
 
     const GURL file_url(params->file_urls[i]);
     fileapi::FileSystemURL file_system_url(
         file_system_context->CrackURL(file_url));
     if (!chromeos::FileSystemBackend::CanHandleURL(file_system_url))
       continue;
     const base::FilePath file_path = file_system_url.path();
 
-    file_urls.push_back(file_url);
+    file_urls->push_back(file_url);
 
     // If MIME type is not provided, guess it from the file path.
     if (mime_type.empty())
       mime_type = file_manager::util::GetMimeTypeForPath(file_path);
 
-    path_mime_set.insert(std::make_pair(file_path, mime_type));
+    path_mime_set->insert(std::make_pair(file_path, mime_type));
   }
 
+  // In case the MIME type of some files are empty,
+  // try to sniff their MIME type by their content.
+  PathAndMimeTypeSet* path_mime_set_ptr = path_mime_set.get();
+  std::vector<GURL>* file_urls_ptr = file_urls.get();
+
+  BrowserThread::PostBlockingPoolTaskAndReply(
+      FROM_HERE,
+      base::Bind(&SniffMimeType, path_mime_set_ptr, file_urls_ptr),
+      base::Bind(
+          &FileBrowserPrivateGetFileTasksFunction::OnSniffingMimeTypeCompleted,
+          this,
+          base::Passed(&path_mime_set),
+          base::Passed(&file_urls)));
+  return true;
+}
+
+void FileBrowserPrivateGetFileTasksFunction::OnSniffingMimeTypeCompleted(
+    scoped_ptr<PathAndMimeTypeSet> path_mime_set,
+    scoped_ptr<std::vector<GURL> > file_urls) {
   std::vector<file_manager::file_tasks::FullTaskDescriptor> tasks;
   file_manager::file_tasks::FindAllTypesOfTasks(
       GetProfile(),
       drive::util::GetDriveAppRegistryByProfile(GetProfile()),
-      path_mime_set,
-      file_urls,
+      *path_mime_set,
+      *file_urls,
       &tasks);
 
   // Convert the tasks into JSON compatible objects.
   using api::file_browser_private::FileTask;
   std::vector<linked_ptr<FileTask> > results;
   for (size_t i = 0; i < tasks.size(); ++i) {
     const file_manager::file_tasks::FullTaskDescriptor& task = tasks[i];
     const linked_ptr<FileTask> converted(new FileTask);
     converted->task_id = file_manager::file_tasks::TaskDescriptorToId(
         task.task_descriptor());
     if (!task.icon_url().is_empty())
       converted->icon_url = task.icon_url().spec();
     converted->title = task.task_title();
     converted->is_default = task.is_default();
     results.push_back(converted);
   }
   results_ = extensions::api::file_browser_private::GetFileTasks::Results::
       Create(results);
   SendResponse(true);
-  return true;
 }
 
 bool FileBrowserPrivateSetDefaultTaskFunction::RunImpl() {
   using extensions::api::file_browser_private::SetDefaultTask::Params;
   const scoped_ptr<Params> params(Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params);
 
   const scoped_refptr<fileapi::FileSystemContext> file_system_context =
       file_manager::util::GetFileSystemContextForRenderViewHost(
           GetProfile(), render_view_host());
@@ skipping 19 matching lines @@
     SetResult(new base::FundamentalValue(true));
     return true;
   }
 
   file_manager::file_tasks::UpdateDefaultTask(
       GetProfile()->GetPrefs(), params->task_id, suffixes, mime_types);
   return true;
 }
 
 }  // namespace extensions