1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
// Copyright (c) 2012 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/common_child/indexed_db/proxy_webidbcursor_impl.h"
#include <vector>
#include "content/common/child_thread.h"
#include "content/common/indexed_db/indexed_db_messages.h"
#include "content/common_child/indexed_db/indexed_db_dispatcher.h"
using WebKit::WebData;
using WebKit::WebIDBCallbacks;
using WebKit::WebIDBKey;
namespace content {
RendererWebIDBCursorImpl::RendererWebIDBCursorImpl(int32 ipc_cursor_id)
: ipc_cursor_id_(ipc_cursor_id),
continue_count_(0),
used_prefetches_(0),
pending_onsuccess_callbacks_(0),
prefetch_amount_(kMinPrefetchAmount) {}
RendererWebIDBCursorImpl::~RendererWebIDBCursorImpl() {
// 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.
IndexedDBDispatcher::Send(
new IndexedDBHostMsg_CursorDestroyed(ipc_cursor_id_));
}
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance();
dispatcher->CursorDestroyed(ipc_cursor_id_);
}
void RendererWebIDBCursorImpl::advance(unsigned long count,
WebIDBCallbacks* callbacks_ptr) {
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance();
scoped_ptr<WebIDBCallbacks> callbacks(callbacks_ptr);
ResetPrefetchCache();
dispatcher->RequestIDBCursorAdvance(
count, callbacks.release(), ipc_cursor_id_);
}
void RendererWebIDBCursorImpl::continueFunction(
const WebIDBKey& key,
WebIDBCallbacks* callbacks_ptr) {
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance();
scoped_ptr<WebIDBCallbacks> callbacks(callbacks_ptr);
if (key.type() == WebIDBKey::NullType) {
// No key, 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(
IndexedDBKey(key), callbacks.release(), ipc_cursor_id_);
}
void RendererWebIDBCursorImpl::postSuccessHandlerCallback() {
pending_onsuccess_callbacks_--;
// If the onsuccess callback called continue() on the cursor again,
// and that continue 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 RendererWebIDBCursorImpl::SetPrefetchData(
const std::vector<IndexedDBKey>& keys,
const std::vector<IndexedDBKey>& primary_keys,
const std::vector<WebData>& 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 RendererWebIDBCursorImpl::CachedContinue(
WebKit::WebIDBCallbacks* callbacks) {
DCHECK_GT(prefetch_keys_.size(), 0ul);
DCHECK(prefetch_primary_keys_.size() == prefetch_keys_.size());
DCHECK(prefetch_values_.size() == prefetch_keys_.size());
IndexedDBKey key = prefetch_keys_.front();
IndexedDBKey primary_key = prefetch_primary_keys_.front();
// this could be a real problem.. we need 2 CachedContinues
WebData value = prefetch_values_.front();
prefetch_keys_.pop_front();
prefetch_primary_keys_.pop_front();
prefetch_values_.pop_front();
used_prefetches_++;
pending_onsuccess_callbacks_++;
callbacks->onSuccess(key, primary_key, value);
}
void RendererWebIDBCursorImpl::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;
}
IndexedDBDispatcher* dispatcher =
IndexedDBDispatcher::ThreadSpecificInstance();
dispatcher->RequestIDBCursorPrefetchReset(
used_prefetches_, prefetch_keys_.size(), ipc_cursor_id_);
prefetch_keys_.clear();
prefetch_primary_keys_.clear();
prefetch_values_.clear();
pending_onsuccess_callbacks_ = 0;
}
} // namespace content
|
