content/browser/indexed_db/indexed_db_cursor.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/indexed_db/indexed_db_cursor.h"
   6
   7 #include <vector>
   8
   9 #include "base/bind.h"
  10 #include "base/logging.h"
  11 #include "content/browser/indexed_db/indexed_db_callbacks.h"
  12 #include "content/browser/indexed_db/indexed_db_database_error.h"
  13 #include "content/browser/indexed_db/indexed_db_tracing.h"
  14 #include "content/browser/indexed_db/indexed_db_transaction.h"
  15 #include "content/browser/indexed_db/indexed_db_value.h"
  16
  17 namespace content {
  18
  19 IndexedDBCursor::IndexedDBCursor(
  20     scoped_ptr<IndexedDBBackingStore::Cursor> cursor,
  21     indexed_db::CursorType cursor_type,
  22     blink::WebIDBTaskType task_type,
  23     IndexedDBTransaction* transaction)
  24     : task_type_(task_type),
  25       cursor_type_(cursor_type),
  26       transaction_(transaction),
  27       cursor_(cursor.Pass()),
  28       closed_(false) {
  29   transaction_->RegisterOpenCursor(this);
  30 }
  31
  32 IndexedDBCursor::~IndexedDBCursor() {
  33   transaction_->UnregisterOpenCursor(this);
  34 }
  35
  36 void IndexedDBCursor::Continue(scoped_ptr<IndexedDBKey> key,
  37                                scoped_ptr<IndexedDBKey> primary_key,
  38                                scoped_refptr<IndexedDBCallbacks> callbacks) {
  39   IDB_TRACE("IndexedDBCursor::Continue");
  40
  41   transaction_->ScheduleTask(
  42       task_type_,
  43       base::Bind(&IndexedDBCursor::CursorIterationOperation,
  44                  this,
  45                  base::Passed(&key),
  46                  base::Passed(&primary_key),
  47                  callbacks));
  48 }
  49
  50 void IndexedDBCursor::Advance(uint32 count,
  51                               scoped_refptr<IndexedDBCallbacks> callbacks) {
  52   IDB_TRACE("IndexedDBCursor::Advance");
  53
  54   transaction_->ScheduleTask(
  55       task_type_,
  56       base::Bind(
  57           &IndexedDBCursor::CursorAdvanceOperation, this, count, callbacks));
  58 }
  59
  60 void IndexedDBCursor::CursorAdvanceOperation(
  61     uint32 count,
  62     scoped_refptr<IndexedDBCallbacks> callbacks,
  63     IndexedDBTransaction* /*transaction*/) {
  64   IDB_TRACE("IndexedDBCursor::CursorAdvanceOperation");
  65   leveldb::Status s;
  66   // TODO(cmumford): Handle this error (crbug.com/363397). Although this will
  67   //                 properly fail, caller will not know why, and any corruption
  68   //                 will be ignored.
  69   if (!cursor_ || !cursor_->Advance(count, &s)) {
  70     cursor_.reset();
  71     callbacks->OnSuccess(nullptr);
  72     return;
  73   }
  74
  75   callbacks->OnSuccess(key(), primary_key(), Value());
  76 }
  77
  78 void IndexedDBCursor::CursorIterationOperation(
  79     scoped_ptr<IndexedDBKey> key,
  80     scoped_ptr<IndexedDBKey> primary_key,
  81     scoped_refptr<IndexedDBCallbacks> callbacks,
  82     IndexedDBTransaction* /*transaction*/) {
  83   IDB_TRACE("IndexedDBCursor::CursorIterationOperation");
  84   leveldb::Status s;
  85   // TODO(cmumford): Handle this error (crbug.com/363397). Although this will
  86   //                 properly fail, caller will not know why, and any corruption
  87   //                 will be ignored.
  88   if (!cursor_ || !cursor_->Continue(key.get(),
  89                                      primary_key.get(),
  90                                      IndexedDBBackingStore::Cursor::SEEK,
  91                                      &s) || !s.ok()) {
  92     cursor_.reset();
  93     callbacks->OnSuccess(nullptr);
  94     return;
  95   }
  96
  97   callbacks->OnSuccess(this->key(), this->primary_key(), Value());
  98 }
  99
 100 void IndexedDBCursor::PrefetchContinue(
 101     int number_to_fetch,
 102     scoped_refptr<IndexedDBCallbacks> callbacks) {
 103   IDB_TRACE("IndexedDBCursor::PrefetchContinue");
 104
 105   transaction_->ScheduleTask(
 106       task_type_,
 107       base::Bind(&IndexedDBCursor::CursorPrefetchIterationOperation,
 108                  this,
 109                  number_to_fetch,
 110                  callbacks));
 111 }
 112
 113 void IndexedDBCursor::CursorPrefetchIterationOperation(
 114     int number_to_fetch,
 115     scoped_refptr<IndexedDBCallbacks> callbacks,
 116     IndexedDBTransaction* /*transaction*/) {
 117   IDB_TRACE("IndexedDBCursor::CursorPrefetchIterationOperation");
 118
 119   std::vector<IndexedDBKey> found_keys;
 120   std::vector<IndexedDBKey> found_primary_keys;
 121   std::vector<IndexedDBValue> found_values;
 122
 123   saved_cursor_.reset();
 124   const size_t max_size_estimate = 10 * 1024 * 1024;
 125   size_t size_estimate = 0;
 126   leveldb::Status s;
 127
 128   // TODO(cmumford): Handle this error (crbug.com/363397). Although this will
 129   //                 properly fail, caller will not know why, and any corruption
 130   //                 will be ignored.
 131   for (int i = 0; i < number_to_fetch; ++i) {
 132     if (!cursor_ || !cursor_->Continue(&s)) {
 133       cursor_.reset();
 134       break;
 135     }
 136
 137     if (i == 0) {
 138       // First prefetched result is always used, so that's the position
 139       // a cursor should be reset to if the prefetch is invalidated.
 140       saved_cursor_.reset(cursor_->Clone());
 141     }
 142
 143     found_keys.push_back(cursor_->key());
 144     found_primary_keys.push_back(cursor_->primary_key());
 145
 146     switch (cursor_type_) {
 147       case indexed_db::CURSOR_KEY_ONLY:
 148         found_values.push_back(IndexedDBValue());
 149         break;
 150       case indexed_db::CURSOR_KEY_AND_VALUE: {
 151         IndexedDBValue value;
 152         value.swap(*cursor_->value());
 153         size_estimate += value.SizeEstimate();
 154         found_values.push_back(value);
 155         break;
 156       }
 157       default:
 158         NOTREACHED();
 159     }
 160     size_estimate += cursor_->key().size_estimate();
 161     size_estimate += cursor_->primary_key().size_estimate();
 162
 163     if (size_estimate > max_size_estimate)
 164       break;
 165   }
 166
 167   if (!found_keys.size()) {
 168     callbacks->OnSuccess(nullptr);
 169     return;
 170   }
 171
 172   callbacks->OnSuccessWithPrefetch(
 173       found_keys, found_primary_keys, &found_values);
 174 }
 175
 176 leveldb::Status IndexedDBCursor::PrefetchReset(int used_prefetches,
 177                                                int /* unused_prefetches */) {
 178   IDB_TRACE("IndexedDBCursor::PrefetchReset");
 179   cursor_.swap(saved_cursor_);
 180   saved_cursor_.reset();
 181   leveldb::Status s;
 182
 183   if (closed_)
 184     return s;
 185   if (cursor_) {
 186     // First prefetched result is always used.
 187     DCHECK_GT(used_prefetches, 0);
 188     for (int i = 0; i < used_prefetches - 1; ++i) {
 189       bool ok = cursor_->Continue(&s);
 190       DCHECK(ok);
 191     }
 192   }
 193
 194   return s;
 195 }
 196
 197 void IndexedDBCursor::Close() {
 198   IDB_TRACE("IndexedDBCursor::Close");
 199   closed_ = true;
 200   cursor_.reset();
 201   saved_cursor_.reset();
 202 }
 203
 204 }  // namespace content