Wired GDataFileSystem::GetFile() method with internal cache.

chrome/browser/chromeos/gdata/gdata_file_system.cc

Index: chrome/browser/chromeos/gdata/gdata_file_system.cc
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system.cc b/chrome/browser/chromeos/gdata/gdata_file_system.cc
index 4d0539528b71375b7292ed89fcbed87530af78d4..0bbeb5a82d3b863a773fb2df43ca684eb884870e 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system.cc
+++ b/chrome/browser/chromeos/gdata/gdata_file_system.cc
@@ -197,6 +197,7 @@ StoreToCacheParams::StoreToCacheParams(
 StoreToCacheParams::~StoreToCacheParams() {
 }
 
+
 //=================== ModifyCacheStatusParams implementations ==================
 
 ModifyCacheStatusParams::ModifyCacheStatusParams(
@@ -538,6 +539,28 @@ GDataFileSystem::CreateDirectoryParams::CreateDirectoryParams(
 GDataFileSystem::CreateDirectoryParams::~CreateDirectoryParams() {
 }
 
+//=================== GetFileFromCacheParams implementation ===================
+
+GDataFileSystem::GetFileFromCacheParams::GetFileFromCacheParams(
+    const FilePath& virtual_file_path,
+    const FilePath& local_tmp_path,
+    const GURL& content_url,
+    const std::string& resource_id,
+    const std::string& md5,
+    scoped_refptr<base::MessageLoopProxy> proxy,
+    const GetFileCallback& callback)
+    : virtual_file_path(virtual_file_path),
+      local_tmp_path(local_tmp_path),
+      content_url(content_url),
+      resource_id(resource_id),
+      md5(md5),
+      proxy(proxy),
+      callback(callback) {
+}
+
+GDataFileSystem::GetFileFromCacheParams::~GetFileFromCacheParams() {
+}
+
 // GDataFileSystem class implementatsion.
 
 GDataFileSystem::GDataFileSystem(Profile* profile,
@@ -1000,9 +1023,12 @@ void GDataFileSystem::CreateDirectory(
 
 void GDataFileSystem::GetFile(const FilePath& file_path,
                               const GetFileCallback& callback) {
-  base::AutoLock lock(lock_);
-  GDataFileBase* file_info = GetGDataFileInfoFromPath(file_path);
-  if (!file_info) {
+  std::string resource_id;
+  std::string md5;
+  GURL content_url;
+  base::PlatformFileInfo file_info;
+  if (!GetFileInfoFromPath(file_path, &file_info,
+                           &resource_id, &md5, &content_url)) {
     if (!callback.is_null()) {
       MessageLoop::current()->PostTask(
           FROM_HERE,
@@ -1013,15 +1039,56 @@ void GDataFileSystem::GetFile(const FilePath& file_path,
     return;
   }
 
-  // TODO(satorux): We should get a file from the cache if it's present, but
-  // the caching layer is not implemented yet. For now, always download from
-  // the cloud.
+  // Returns absolute path of the file if it were cached or to be cached.
+  FilePath local_tmp_path = GetCacheFilePath(resource_id, md5, CACHE_TYPE_TMP,
+      false  /* is_local */);

[kuan, 2012/03/20 03:22:19]

nit: align "false" with "resource_id"

[zel, 2012/03/20 04:31:17]

Done.

+  // Checks if file corresponding to |resource_id| and |md5| exist on disk and
+  // can be accessed i.e. not corrupted by previous file operations that didn't
+  // complete for whatever reasons.
+  // Initializes cache if it has not been initialized.
+  // Upon completion, |callback| is invoked on the thread where this method was
+  // called with the cache file path if it exists and is accessible or empty
+  // otherwise.

[kuan, 2012/03/20 03:22:19]

not sure if u really mean to copy and paste the comments from header file to
here?

[zel, 2012/03/20 04:31:17]

Removed.

+  GetFromCache(resource_id, md5,
+               base::Bind(
+                   &GDataFileSystem::OnGetFileFromCache,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   GetFileFromCacheParams(file_path,
+                                          local_tmp_path,
+                                          content_url,
+                                          resource_id,
+                                          md5,
+                                          base::MessageLoopProxy::current(),
+                                          callback)));
+}
+
+void GDataFileSystem::OnGetFileFromCache(
+        const GetFileFromCacheParams& params,
+        base::PlatformFileError error,
+        const std::string& resource_id,
+        const std::string& md5,
+        const FilePath& gdata_file_path,
+        const FilePath& cache_file_path) {

[kuan, 2012/03/20 03:22:19]

nit: only 4 spaces needed for indentation

[zel, 2012/03/20 04:31:17]

Done.

+  // Have we found the file in cache? If so, return it back to the caller.
+  if (error == base::PLATFORM_FILE_OK) {
+    if (!params.callback.is_null()) {
+      params.proxy->PostTask(FROM_HERE,
+                             base::Bind(params.callback,
+                                        error,
+                                        cache_file_path));
+    }
+
+    return;
+  }
+
+  // If cache file is not found, try to download it from the server instead.
   documents_service_->DownloadFile(
-      file_info->GetFilePath(),
-      file_info->content_url(),
+      params.virtual_file_path,
+      params.local_tmp_path,
+      params.content_url,
       base::Bind(&GDataFileSystem::OnFileDownloaded,
                  weak_ptr_factory_.GetWeakPtr(),
-                 callback));
+                 params));
 }
 
 void GDataFileSystem::InitiateUpload(
@@ -1148,13 +1215,26 @@ void GDataFileSystem::UnsafeFindFileByPath(
 }
 
 bool GDataFileSystem::GetFileInfoFromPath(
-    const FilePath& file_path, base::PlatformFileInfo* file_info) {
+    const FilePath& file_path, base::PlatformFileInfo* file_info,
+    std::string* resource_id, std::string* md5, GURL* content_url) {
+  DCHECK(file_info);
   base::AutoLock lock(lock_);
   GDataFileBase* file = GetGDataFileInfoFromPath(file_path);
   if (!file)
     return false;
 
   *file_info = file->file_info();
+  if (resource_id)
+    *resource_id = file->resource_id();
+
+  GDataFile* regular_file = file->AsGDataFile();
+  if (regular_file) {
+    if (md5)
+      *md5 = regular_file->file_md5();
+
+    if (content_url)
+      *content_url = regular_file->content_url();
+  }
   return true;
 }
 
@@ -1653,15 +1733,35 @@ void GDataFileSystem::OnRemovedDocument(
 }
 
 void GDataFileSystem::OnFileDownloaded(
-    const GetFileCallback& callback,
+    const GetFileFromCacheParams& params,
     GDataErrorCode status,
     const GURL& content_url,
-    const FilePath& file_path) {
+    const FilePath& downloaded_file_path) {
   base::PlatformFileError error = GDataToPlatformError(status);
 
-  if (!callback.is_null()) {
-    callback.Run(error, file_path);
+  // Make sure that downloaded file is properly stored in cache. We don't have
+  // to wait for this operation to finish since the user can already use the
+  // downloaded file.
+  if (error == base::PLATFORM_FILE_OK) {
+    StoreToCache(params.resource_id,
+                 params.md5,
+                 downloaded_file_path,
+                 base::Bind(&GDataFileSystem::OnStoreToCache,
+                            weak_ptr_factory_.GetWeakPtr()));
+
   }
+  if (!params.callback.is_null()) {
+    params.proxy->PostTask(FROM_HERE,
+                           base::Bind(params.callback,
+                                      error,
+                                      downloaded_file_path));
+  }
+}
+
+void GDataFileSystem::OnStoreToCache(base::PlatformFileError error,
+                                     const std::string& resource_id,
+                                     const std::string& md5) {
+  // Nothing much to do here for now.
 }
 
 base::PlatformFileError GDataFileSystem::RenameFileOnFilesystem(