Revert of Reland of "Remove void** from disk_cache interface."

net/disk_cache/simple/simple_backend_impl.cc

 // Copyright (c) 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 "net/disk_cache/simple/simple_backend_impl.h"
 
 #include <algorithm>
 #include <cstdlib>
 #include <functional>
 
@@ skipping 455 matching lines @@
       base::Bind(&SimpleBackendImpl::IndexReadyForDoom, AsWeakPtr(),
                  initial_time, end_time, callback));
 }
 
 int SimpleBackendImpl::DoomEntriesSince(
     const Time initial_time,
     const CompletionCallback& callback) {
   return DoomEntriesBetween(initial_time, Time(), callback);
 }
 
-class SimpleBackendImpl::SimpleIterator FINAL : public Iterator {
- public:
-  explicit SimpleIterator(base::WeakPtr<SimpleBackendImpl> backend)
-      : backend_(backend),
-        weak_factory_(this) {
-  }
+int SimpleBackendImpl::OpenNextEntry(void** iter,
+                                     Entry** next_entry,
+                                     const CompletionCallback& callback) {
+  CompletionCallback get_next_entry =
+      base::Bind(&SimpleBackendImpl::GetNextEntryInIterator, AsWeakPtr(), iter,
+                 next_entry, callback);
+  return index_->ExecuteWhenReady(get_next_entry);
+}
 
-  // From Backend::Iterator:
-  virtual int OpenNextEntry(Entry** next_entry,
-                            const CompletionCallback& callback) OVERRIDE {
-    CompletionCallback open_next_entry_impl =
-        base::Bind(&SimpleIterator::OpenNextEntryImpl,
-                   weak_factory_.GetWeakPtr(), next_entry, callback);
-    return backend_->index_->ExecuteWhenReady(open_next_entry_impl);
-  }
-
-  void OpenNextEntryImpl(Entry** next_entry,
-                         const CompletionCallback& callback,
-                         int index_initialization_error_code) {
-    if (!backend_) {
-      callback.Run(net::ERR_FAILED);
-      return;
-    }
-    if (index_initialization_error_code != net::OK) {
-      callback.Run(index_initialization_error_code);
-      return;
-    }
-    if (!hashes_to_enumerate_)
-      hashes_to_enumerate_ = backend_->index()->GetAllHashes().Pass();
-
-    while (!hashes_to_enumerate_->empty()) {
-      uint64 entry_hash = hashes_to_enumerate_->back();
-      hashes_to_enumerate_->pop_back();
-      if (backend_->index()->Has(entry_hash)) {
-        *next_entry = NULL;
-        CompletionCallback continue_iteration = base::Bind(
-            &SimpleIterator::CheckIterationReturnValue,
-            weak_factory_.GetWeakPtr(),
-            next_entry,
-            callback);
-        int error_code_open = backend_->OpenEntryFromHash(entry_hash,
-                                                          next_entry,
-                                                          continue_iteration);
-        if (error_code_open == net::ERR_IO_PENDING)
-          return;
-        if (error_code_open != net::ERR_FAILED) {
-          callback.Run(error_code_open);
-          return;
-        }
-      }
-    }
-    callback.Run(net::ERR_FAILED);
-  }
-
-  void CheckIterationReturnValue(Entry** entry,
-                                 const CompletionCallback& callback,
-                                 int error_code) {
-    if (error_code == net::ERR_FAILED) {
-      OpenNextEntry(entry, callback);
-      return;
-    }
-    callback.Run(error_code);
-  }
-
- private:
-  base::WeakPtr<SimpleBackendImpl> backend_;
-  scoped_ptr<std::vector<uint64> > hashes_to_enumerate_;
-  base::WeakPtrFactory<SimpleIterator> weak_factory_;
-};
-
-scoped_ptr<Backend::Iterator> SimpleBackendImpl::CreateIterator() {
-  return scoped_ptr<Iterator>(new SimpleIterator(AsWeakPtr()));
+void SimpleBackendImpl::EndEnumeration(void** iter) {
+  active_enumerations_.Remove(IteratorToEnumerationId(iter));
+  *iter = NULL;
 }
 
 void SimpleBackendImpl::GetStats(
     std::vector<std::pair<std::string, std::string> >* stats) {
   std::pair<std::string, std::string> item;
   item.first = "Cache type";
   item.second = "Simple Cache";
   stats->push_back(item);
 }
 
 void SimpleBackendImpl::OnExternalCacheHit(const std::string& key) {
   index_->UseIfExists(simple_util::GetEntryHashKey(key));
 }
 
+// static
+SimpleBackendImpl::ActiveEnumerationMap::KeyType
+    SimpleBackendImpl::IteratorToEnumerationId(void** iter) {
+  COMPILE_ASSERT(sizeof(ptrdiff_t) >= sizeof(*iter),
+                 integer_type_must_fit_ptr_type_for_cast_to_be_reversible);
+  const ptrdiff_t ptrdiff_enumeration_id = reinterpret_cast<ptrdiff_t>(*iter);
+  const ActiveEnumerationMap::KeyType enumeration_id = ptrdiff_enumeration_id;
+  DCHECK_EQ(enumeration_id, ptrdiff_enumeration_id);
+  return enumeration_id;
+}
+
+// static
+void* SimpleBackendImpl::EnumerationIdToIterator(
+    ActiveEnumerationMap::KeyType enumeration_id) {
+  const ptrdiff_t ptrdiff_enumeration_id = enumeration_id;
+  DCHECK_EQ(enumeration_id, ptrdiff_enumeration_id);
+  COMPILE_ASSERT(sizeof(ptrdiff_t) >= sizeof(void*),
+                 integer_type_must_fit_ptr_type_for_cast_to_be_reversible);
+  return reinterpret_cast<void*>(ptrdiff_enumeration_id);
+}
+
 void SimpleBackendImpl::InitializeIndex(const CompletionCallback& callback,
                                         const DiskStatResult& result) {
   if (result.net_error == net::OK) {
     index_->SetMaxSize(result.max_size);
     index_->Initialize(result.cache_dir_mtime);
   }
   callback.Run(result.net_error);
 }
 
 SimpleBackendImpl::DiskStatResult SimpleBackendImpl::InitCacheStructureOnDisk(
@@ skipping 93 matching lines @@
     return active_it->second->DoomEntry(callback);
 
   // There's no pending dooms, nor any open entry. We can make a trivial
   // call to DoomEntries() to delete this entry.
   std::vector<uint64> entry_hash_vector;
   entry_hash_vector.push_back(entry_hash);
   DoomEntries(&entry_hash_vector, callback);
   return net::ERR_IO_PENDING;
 }
 
+void SimpleBackendImpl::GetNextEntryInIterator(
+    void** iter,
+    Entry** next_entry,
+    const CompletionCallback& callback,
+    int error_code) {
+  if (error_code != net::OK) {
+    callback.Run(error_code);
+    return;
+  }
+  std::vector<uint64>* entry_list = NULL;
+  if (*iter == NULL) {
+    const ActiveEnumerationMap::KeyType new_enumeration_id =
+        active_enumerations_.Add(
+            entry_list = index()->GetAllHashes().release());
+    *iter = EnumerationIdToIterator(new_enumeration_id);
+  } else {
+    entry_list = active_enumerations_.Lookup(IteratorToEnumerationId(iter));
+  }
+  while (entry_list->size() > 0) {
+    uint64 entry_hash = entry_list->back();
+    entry_list->pop_back();
+    if (index()->Has(entry_hash)) {
+      *next_entry = NULL;
+      CompletionCallback continue_iteration = base::Bind(
+          &SimpleBackendImpl::CheckIterationReturnValue,
+          AsWeakPtr(),
+          iter,
+          next_entry,
+          callback);
+      int error_code_open = OpenEntryFromHash(entry_hash,
+                                              next_entry,
+                                              continue_iteration);
+      if (error_code_open == net::ERR_IO_PENDING)
+        return;
+      if (error_code_open != net::ERR_FAILED) {
+        callback.Run(error_code_open);
+        return;
+      }
+    }
+  }
+  callback.Run(net::ERR_FAILED);
+}
+
 void SimpleBackendImpl::OnEntryOpenedFromHash(
     uint64 hash,
     Entry** entry,
     const scoped_refptr<SimpleEntryImpl>& simple_entry,
     const CompletionCallback& callback,
     int error_code) {
   if (error_code != net::OK) {
     callback.Run(error_code);
     return;
   }
@@ skipping 33 matching lines @@
       simple_entry->Close();
       final_code = net::ERR_FAILED;
     } else {
       DCHECK_EQ(simple_entry->entry_hash(), simple_util::GetEntryHashKey(key));
     }
     SIMPLE_CACHE_UMA(BOOLEAN, "KeyMatchedOnOpen", cache_type_, key_matches);
   }
   callback.Run(final_code);
 }
 
+void SimpleBackendImpl::CheckIterationReturnValue(
+    void** iter,
+    Entry** entry,
+    const CompletionCallback& callback,
+    int error_code) {
+  if (error_code == net::ERR_FAILED) {
+    OpenNextEntry(iter, entry, callback);
+    return;
+  }
+  callback.Run(error_code);
+}
+
 void SimpleBackendImpl::DoomEntriesComplete(
     scoped_ptr<std::vector<uint64> > entry_hashes,
     const net::CompletionCallback& callback,
     int result) {
   std::for_each(
       entry_hashes->begin(), entry_hashes->end(),
       std::bind1st(std::mem_fun(&SimpleBackendImpl::OnDoomComplete),
                    this));
   callback.Run(result);
 }
 
 void SimpleBackendImpl::FlushWorkerPoolForTesting() {
   if (g_sequenced_worker_pool)
     g_sequenced_worker_pool->FlushForTesting();
 }
 
 }  // namespace disk_cache