Reland of "Remove void** from disk_cache interface" w/ blockfile iter fix.

Enumeration and iteration were passing around void**. With this CL, we
instead use an Iterator object.

TBR=jkarlin@chromium.org,rvargas@chromium.org,clamy@chromium.org,piman@chromium.org
BUG=413644,416059
TEST=None

Review URL: https://codereview.chromium.org/588243002

Cr-Commit-Position: refs/heads/master@{#296415}

2 files changed, 23 insertions, 20 deletions

diff --git a/content/browser/gpu/shader_disk_cache.cc b/content/browser/gpu/shader_disk_cache.cc
index a7f240c..c97fd9e 100644
--- a/content/browser/gpu/shader_disk_cache.cc
+++ b/content/browser/gpu/shader_disk_cache.cc
@@ -23,6 +23,9 @@ void EntryCloser(disk_cache::Entry* entry) {
   entry->Close();
 }
 
+void FreeDiskCacheIterator(scoped_ptr<disk_cache::Backend::Iterator> iterator) {
+}
+
 }  // namespace
 
 // ShaderDiskCacheEntry handles the work of caching/updating the cached
@@ -95,7 +98,7 @@ class ShaderDiskReadHelper
 
   base::WeakPtr<ShaderDiskCache> cache_;
   OpType op_type_;
-  void* iter_;
+  scoped_ptr<disk_cache::Backend::Iterator> iter_;
   scoped_refptr<net::IOBufferWithSize> buf_;
   int host_id_;
   disk_cache::Entry* entry_;
@@ -243,7 +246,6 @@ ShaderDiskReadHelper::ShaderDiskReadHelper(
     int host_id)
     : cache_(cache),
       op_type_(OPEN_NEXT),
-      iter_(NULL),
       buf_(NULL),
       host_id_(host_id),
       entry_(NULL) {
@@ -291,16 +293,17 @@ int ShaderDiskReadHelper::OpenNextEntry() {
   DCHECK(CalledOnValidThread());
   // Called through OnOpComplete, so we know |cache_| is valid.
   op_type_ = OPEN_NEXT_COMPLETE;
-  return cache_->backend()->OpenNextEntry(
-      &iter_,
-      &entry_,
-      base::Bind(&ShaderDiskReadHelper::OnOpComplete, this));
+  if (!iter_)
+    iter_ = cache_->backend()->CreateIterator();
+  return iter_->OpenNextEntry(
+      &entry_, base::Bind(&ShaderDiskReadHelper::OnOpComplete, this));
 }
 
 int ShaderDiskReadHelper::OpenNextEntryComplete(int rv) {
   DCHECK(CalledOnValidThread());
   // Called through OnOpComplete, so we know |cache_| is valid.
   if (rv == net::ERR_FAILED) {
+    iter_.reset();
     op_type_ = ITERATION_FINISHED;
     return net::OK;
   }
@@ -339,16 +342,21 @@ int ShaderDiskReadHelper::ReadComplete(int rv) {
 int ShaderDiskReadHelper::IterationComplete(int rv) {
   DCHECK(CalledOnValidThread());
   // Called through OnOpComplete, so we know |cache_| is valid.
-  cache_->backend()->EndEnumeration(&iter_);
-  iter_ = NULL;
+  iter_.reset();
   op_type_ = TERMINATE;
   return net::OK;
 }
 
 ShaderDiskReadHelper::~ShaderDiskReadHelper() {
-  if (entry_)
+  if (entry_) {
     BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
                             base::Bind(&EntryCloser, entry_));
+  }
+  if (iter_) {
+    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+                            base::Bind(&FreeDiskCacheIterator,
+                                       base::Passed(&iter_)));
+  }
 }
 
 ShaderClearHelper::ShaderClearHelper(scoped_refptr<ShaderDiskCache> cache,
diff --git a/content/browser/service_worker/service_worker_cache.cc b/content/browser/service_worker/service_worker_cache.cc
index 9c16df0..6bf5acb 100644
--- a/content/browser/service_worker/service_worker_cache.cc
+++ b/content/browser/service_worker/service_worker_cache.cc
@@ -645,7 +645,6 @@ struct ServiceWorkerCache::KeysContext {
       : original_callback(callback),
         cache(cache),
         out_keys(new ServiceWorkerCache::Requests()),
-        backend_iterator(NULL),
         enumerated_entry(NULL) {}
 
   ~KeysContext() {
@@ -653,8 +652,6 @@ struct ServiceWorkerCache::KeysContext {
       entries[i]->Close();
     if (enumerated_entry)
       enumerated_entry->Close();
-    if (cache && backend_iterator && cache->backend_)
-      cache->backend_->EndEnumeration(&backend_iterator);
   }
 
   // The callback passed to the Keys() function.
@@ -670,7 +667,7 @@ struct ServiceWorkerCache::KeysContext {
   scoped_ptr<ServiceWorkerCache::Requests> out_keys;
 
   // Used for enumerating cache entries.
-  void* backend_iterator;
+  scoped_ptr<disk_cache::Backend::Iterator> backend_iterator;
   disk_cache::Entry* enumerated_entry;
 };
 
@@ -822,14 +819,14 @@ void ServiceWorkerCache::Keys(const RequestsCallback& callback) {
   scoped_ptr<KeysContext> keys_context(
       new KeysContext(callback, weak_ptr_factory_.GetWeakPtr()));
 
-  void** backend_iterator = &keys_context->backend_iterator;
+  keys_context->backend_iterator = backend_->CreateIterator();
+  disk_cache::Backend::Iterator& iterator = *keys_context->backend_iterator;
   disk_cache::Entry** enumerated_entry = &keys_context->enumerated_entry;
 
   net::CompletionCallback open_entry_callback =
       base::Bind(KeysDidOpenNextEntry, base::Passed(keys_context.Pass()));
 
-  int rv = backend_->OpenNextEntry(
-      backend_iterator, enumerated_entry, open_entry_callback);
+  int rv = iterator.OpenNextEntry(enumerated_entry, open_entry_callback);
 
   if (rv != net::ERR_IO_PENDING)
     open_entry_callback.Run(rv);
@@ -912,14 +909,12 @@ void ServiceWorkerCache::KeysDidOpenNextEntry(
   keys_context->enumerated_entry = NULL;
 
   // Enumerate the next entry.
-  void** backend_iterator = &keys_context->backend_iterator;
+  disk_cache::Backend::Iterator& iterator = *keys_context->backend_iterator;
   disk_cache::Entry** enumerated_entry = &keys_context->enumerated_entry;
-
   net::CompletionCallback open_entry_callback =
       base::Bind(KeysDidOpenNextEntry, base::Passed(keys_context.Pass()));
 
-  rv = cache->backend_->OpenNextEntry(
-      backend_iterator, enumerated_entry, open_entry_callback);
+  rv = iterator.OpenNextEntry(enumerated_entry, open_entry_callback);
 
   if (rv != net::ERR_IO_PENDING)
     open_entry_callback.Run(rv);