Unlink corrupt SimpleCache index files immediately after load.

net/disk_cache/simple/simple_index_file.cc

Index: net/disk_cache/simple/simple_index_file.cc
diff --git a/net/disk_cache/simple/simple_index_file.cc b/net/disk_cache/simple/simple_index_file.cc
index 529faf15a1ed1c71ecb6a616f3c5480134dfc2b6..c6bc6eaf891dc1a55cc3bd0c3517792324bace1c 100644
--- a/net/disk_cache/simple/simple_index_file.cc
+++ b/net/disk_cache/simple/simple_index_file.cc
@@ -6,6 +6,7 @@
 
 #include <vector>
 
+#include <base/bind_helpers.h>
 #include "base/file_util.h"
 #include "base/files/file_enumerator.h"
 #include "base/hash.h"
@@ -175,13 +176,23 @@ bool SimpleIndexFile::IsIndexFileStale(const base::FilePath& index_filename) {
 // static
 scoped_ptr<SimpleIndex::EntrySet> SimpleIndexFile::LoadFromDisk(
     const base::FilePath& index_filename) {
+  base::ScopedClosureRunner
+      scoped_index_deleter(base::Bind(base::IgnoreResult(&file_util::Delete),
+                                      index_filename, false));
+
   std::string contents;
   if (!file_util::ReadFileToString(index_filename, &contents)) {
     LOG(WARNING) << "Could not read Simple Index file.";
     return scoped_ptr<SimpleIndex::EntrySet>();
   }
 
-  return SimpleIndexFile::Deserialize(contents.data(), contents.size());
+  scoped_ptr<SimpleIndex::EntrySet> entries =
+      SimpleIndexFile::Deserialize(contents.data(), contents.size());
+  if (!entries)
+    return scoped_ptr<SimpleIndex::EntrySet>();
+
+  scoped_index_deleter.Release();

[pasko, 2013/06/20 13:52:22]

I don't like using automatic closure runner in this simple function. It
complicates the matter because of wtf-always-deleting-the-index until the very
end of the function where there is a Release(). Also it runs base::Bind and
other memory allocation heavy lifting only to throw everything away in .9999% of
cases.

I know, lisp-ish code looks beautiful, but could you just call
file_util::Delete(index_filename, false) on the two return paths? It will be
less lines of code and less metaprogramming.

[gavinp, 2013/06/20 20:18:18]

Done. I was only trying to show off that I knew about base::IgnoreResult anyway,
and now that's done!

+  return entries.Pass();
 }
 
 // static