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// Copyright 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 "content/child/indexed_db/webidbcursor_impl.h"
#include <string>
#include <vector>
#include "content/child/indexed_db/indexed_db_dispatcher.h"
#include "content/child/indexed_db/indexed_db_key_builders.h"
#include "content/child/thread_safe_sender.h"
#include "content/common/indexed_db/indexed_db_messages.h"
#include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBValue.h"
using blink::WebBlobInfo;
using blink::WebData;
using blink::WebIDBCallbacks;
using blink::WebIDBKey;
using blink::WebIDBValue;
namespace content {
WebIDBCursorImpl::WebIDBCursorImpl(int32 ipc_cursor_id,
int64 transaction_id,
ThreadSafeSender* thread_safe_sender)
: ipc_cursor_id_(ipc_cursor_id),
transaction_id_(transaction_id),
continue_count_(0),
used_prefetches_(0),
pending_onsuccess_callbacks_(0),
prefetch_amount_(kMinPrefetchAmount),
thread_safe_sender_(thread_safe_sender) {}
WebIDBCursorImpl::~WebIDBCursorImpl() {
// It's not possible for there to be pending callbacks that address this
// object since inside WebKit, they hold a reference to the object which owns
// this object. But, if that ever changed, then we'd need to invalidate
// any such pointers.
if (ipc_cursor_id_ != kInvalidCursorId) {
// Invalid ID used in tests to avoid really sending this message.
thread_safe_sender_->Send(
new IndexedDBHostMsg_CursorDestroyed(ipc_cursor_id_));
}
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance(thread_safe_sender_.get());
dispatcher->CursorDestroyed(ipc_cursor_id_);
}
void WebIDBCursorImpl::advance(unsigned long count,
WebIDBCallbacks* callbacks_ptr) {
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance(thread_safe_sender_.get());
scoped_ptr<WebIDBCallbacks> callbacks(callbacks_ptr);
if (count <= prefetch_keys_.size()) {
CachedAdvance(count, callbacks.get());
return;
}
ResetPrefetchCache();
dispatcher->RequestIDBCursorAdvance(
count, callbacks.release(), ipc_cursor_id_, transaction_id_);
}
void WebIDBCursorImpl::continueFunction(const WebIDBKey& key,
WebIDBCallbacks* callbacks_ptr) {
continueFunction(key, WebIDBKey::createNull(), callbacks_ptr);
}
void WebIDBCursorImpl::continueFunction(const WebIDBKey& key,
const WebIDBKey& primary_key,
WebIDBCallbacks* callbacks_ptr) {
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance(thread_safe_sender_.get());
scoped_ptr<WebIDBCallbacks> callbacks(callbacks_ptr);
if (key.keyType() == blink::WebIDBKeyTypeNull &&
primary_key.keyType() == blink::WebIDBKeyTypeNull) {
// No key(s), so this would qualify for a prefetch.
++continue_count_;
if (!prefetch_keys_.empty()) {
// We have a prefetch cache, so serve the result from that.
CachedContinue(callbacks.get());
return;
}
if (continue_count_ > kPrefetchContinueThreshold) {
// Request pre-fetch.
++pending_onsuccess_callbacks_;
dispatcher->RequestIDBCursorPrefetch(
prefetch_amount_, callbacks.release(), ipc_cursor_id_);
// Increase prefetch_amount_ exponentially.
prefetch_amount_ *= 2;
if (prefetch_amount_ > kMaxPrefetchAmount)
prefetch_amount_ = kMaxPrefetchAmount;
return;
}
} else {
// Key argument supplied. We couldn't prefetch this.
ResetPrefetchCache();
}
dispatcher->RequestIDBCursorContinue(IndexedDBKeyBuilder::Build(key),
IndexedDBKeyBuilder::Build(primary_key),
callbacks.release(),
ipc_cursor_id_,
transaction_id_);
}
void WebIDBCursorImpl::postSuccessHandlerCallback() {
pending_onsuccess_callbacks_--;
// If the onsuccess callback called continue()/advance() on the cursor
// again, and that request was served by the prefetch cache, then
// pending_onsuccess_callbacks_ would be incremented. If not, it means the
// callback did something else, or nothing at all, in which case we need to
// reset the cache.
if (pending_onsuccess_callbacks_ == 0)
ResetPrefetchCache();
}
void WebIDBCursorImpl::SetPrefetchData(
const std::vector<IndexedDBKey>& keys,
const std::vector<IndexedDBKey>& primary_keys,
const std::vector<WebIDBValue>& values) {
prefetch_keys_.assign(keys.begin(), keys.end());
prefetch_primary_keys_.assign(primary_keys.begin(), primary_keys.end());
prefetch_values_.assign(values.begin(), values.end());
used_prefetches_ = 0;
pending_onsuccess_callbacks_ = 0;
}
void WebIDBCursorImpl::CachedAdvance(unsigned long count,
WebIDBCallbacks* callbacks) {
DCHECK_GE(prefetch_keys_.size(), count);
DCHECK_EQ(prefetch_primary_keys_.size(), prefetch_keys_.size());
DCHECK_EQ(prefetch_values_.size(), prefetch_keys_.size());
while (count > 1) {
prefetch_keys_.pop_front();
prefetch_primary_keys_.pop_front();
prefetch_values_.pop_front();
++used_prefetches_;
--count;
}
CachedContinue(callbacks);
}
void WebIDBCursorImpl::CachedContinue(WebIDBCallbacks* callbacks) {
DCHECK_GT(prefetch_keys_.size(), 0ul);
DCHECK_EQ(prefetch_primary_keys_.size(), prefetch_keys_.size());
DCHECK_EQ(prefetch_values_.size(), prefetch_keys_.size());
IndexedDBKey key = prefetch_keys_.front();
IndexedDBKey primary_key = prefetch_primary_keys_.front();
WebIDBValue value = prefetch_values_.front();
prefetch_keys_.pop_front();
prefetch_primary_keys_.pop_front();
prefetch_values_.pop_front();
++used_prefetches_;
++pending_onsuccess_callbacks_;
if (!continue_count_) {
// The cache was invalidated by a call to ResetPrefetchCache()
// after the RequestIDBCursorPrefetch() was made. Now that the
// initiating continue() call has been satisfied, discard
// the rest of the cache.
ResetPrefetchCache();
}
callbacks->onSuccess(WebIDBKeyBuilder::Build(key),
WebIDBKeyBuilder::Build(primary_key), value);
}
void WebIDBCursorImpl::ResetPrefetchCache() {
continue_count_ = 0;
prefetch_amount_ = kMinPrefetchAmount;
if (!prefetch_keys_.size()) {
// No prefetch cache, so no need to reset the cursor in the back-end.
return;
}
// Ack any unused blobs.
std::vector<std::string> uuids;
for (const auto& value : prefetch_values_) {
for (size_t i = 0, size = value.webBlobInfo.size(); i < size; ++i)
uuids.push_back(value.webBlobInfo[i].uuid().latin1());
}
if (!uuids.empty())
thread_safe_sender_->Send(new IndexedDBHostMsg_AckReceivedBlobs(uuids));
// Reset the back-end cursor.
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance(thread_safe_sender_.get());
dispatcher->RequestIDBCursorPrefetchReset(
used_prefetches_, prefetch_keys_.size(), ipc_cursor_id_);
// Reset the prefetch cache.
prefetch_keys_.clear();
prefetch_primary_keys_.clear();
prefetch_values_.clear();
pending_onsuccess_callbacks_ = 0;
}
} // namespace content
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