Adding UMA stats for requestFileSystem error analysis.

webkit/fileapi/sandbox_mount_point_provider.cc

Index: webkit/fileapi/sandbox_mount_point_provider.cc
diff --git a/webkit/fileapi/sandbox_mount_point_provider.cc b/webkit/fileapi/sandbox_mount_point_provider.cc
index 25b4f233cb1ffc61bdbbfc1675ce6e2c22b86805..661d760ffab35a2fcd12623a95da155b664d3c0d 100644
--- a/webkit/fileapi/sandbox_mount_point_provider.cc
+++ b/webkit/fileapi/sandbox_mount_point_provider.cc
@@ -14,6 +14,7 @@
 #include "base/rand_util.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
+#include "base/metrics/histogram.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/net_util.h"
 #include "webkit/fileapi/file_system_operation_context.h"
@@ -36,6 +37,15 @@ static const int kOldFileSystemUniqueLength = 16;
 static const unsigned kOldFileSystemUniqueDirectoryNameLength =
     kOldFileSystemUniqueLength + arraysize(kOldFileSystemUniqueNamePrefix) - 1;
 
+const char kOpenFileSystem[] = "FileSystem.OpenFileSystem";
+enum FileSystemError {
+  kOK = 0,
+  kIncognito,
+  kInvalidScheme,
+  kCreateDirectoryError,
+  kFileSystemErrorMax,
+};
+
 // Restricted names.
 // http://dev.w3.org/2009/dap/file-system/file-dir-sys.html#naming-restrictions
 static const char* const kRestrictedNames[] = {
@@ -343,6 +353,11 @@ class SandboxMountPointProvider::GetFileSystemRootPathTask
   }
 
   void DispatchCallbackOnCallerThread(const FilePath& root_path) {
+    if (root_path.empty()) {
+      UMA_HISTOGRAM_ENUMERATION(kOpenFileSystem,
+                                kCreateDirectoryError,
+                                kFileSystemErrorMax);

[kinuko, 2011/12/15 04:34:05]

Tzik-san, I know this patch has been already landed but could we add slightly
more detailed metrics for this case?
GetDirectoryForOriginAndType could fail for various reasons and I suspect this
one would be the primary hot error spot.
(For example if it's failing due to CURRENT file corruption in origin db like
the one reported in 103018 the error must come from GetDirectoryForOrigin() =>
OriginDatabase::GetPathForOrigin() => OriginDatabase::Init().

+    }
     origin_message_loop_proxy_->PostTask(
         FROM_HERE,
         base::Bind(&GetFileSystemRootPathTask::DispatchCallback, this,
@@ -355,6 +370,10 @@ class SandboxMountPointProvider::GetFileSystemRootPathTask
         FileSystemPathManager::GetFileSystemTypeString(type_);
     DCHECK(!type_string.empty());
     std::string name = origin_identifier + ":" + type_string;
+
+    if (!root_path.empty())
+      UMA_HISTOGRAM_ENUMERATION(kOpenFileSystem, kOK, kFileSystemErrorMax);
+
     callback_.Run(!root_path.empty(), root_path, name);
     callback_.Reset();
   }
@@ -425,11 +444,17 @@ void SandboxMountPointProvider::ValidateFileSystemRootAndGetURL(
   if (path_manager_->is_incognito()) {
     // TODO(kinuko): return an isolated temporary directory.
     callback.Run(false, FilePath(), std::string());
+    UMA_HISTOGRAM_ENUMERATION(kOpenFileSystem,
+                              kIncognito,
+                              kFileSystemErrorMax);
     return;
   }
 
   if (!path_manager_->IsAllowedScheme(origin_url)) {
     callback.Run(false, FilePath(), std::string());
+    UMA_HISTOGRAM_ENUMERATION(kOpenFileSystem,
+                              kInvalidScheme,
+                              kFileSystemErrorMax);
     return;
   }