storage/mozStorageStatementData.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: sw=2 ts=2 sts=2 et
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozStorageStatementData_h
   8 #define mozStorageStatementData_h
   9
  10 #include "sqlite3.h"
  11
  12 #include "nsTArray.h"
  13 #include "MainThreadUtils.h"
  14
  15 #include "mozStorageBindingParamsArray.h"
  16 #include "mozStorageConnection.h"
  17 #include "StorageBaseStatementInternal.h"
  18 #include "mozStoragePrivateHelpers.h"
  19
  20 struct sqlite3_stmt;
  21
  22 namespace mozilla {
  23 namespace storage {
  24
  25 class StatementData {
  26  public:
  27   StatementData(sqlite3_stmt* aStatement,
  28                 already_AddRefed<BindingParamsArray> aParamsArray,
  29                 StorageBaseStatementInternal* aStatementOwner)
  30       : mStatement(aStatement),
  31         mParamsArray(aParamsArray),
  32         mQueryStatusRecorded(false),
  33         mStatementOwner(aStatementOwner) {
  34     MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
  35   }
  36   StatementData(const StatementData& aSource)
  37       : mStatement(aSource.mStatement),
  38         mParamsArray(aSource.mParamsArray),
  39         mQueryStatusRecorded(false),
  40         mStatementOwner(aSource.mStatementOwner) {
  41     MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
  42   }
  43   StatementData() : mStatement(nullptr), mQueryStatusRecorded(false) {}
  44   ~StatementData() {
  45     // We need to ensure that mParamsArray is released on the main thread,
  46     // as the binding arguments may be XPConnect values, which are safe
  47     // to release only on the main thread.
  48     NS_ReleaseOnMainThread("StatementData::mParamsArray",
  49                            mParamsArray.forget());
  50   }
  51
  52   /**
  53    * Return the sqlite statement, fetching it from the storage statement.  In
  54    * the case of AsyncStatements this may actually create the statement
  55    */
  56   inline int getSqliteStatement(sqlite3_stmt** _stmt) {
  57     if (!mStatement) {
  58       int rc = mStatementOwner->getAsyncStatement(&mStatement);
  59       MaybeRecordQueryStatus(rc);
  60       NS_ENSURE_TRUE(rc == SQLITE_OK, rc);
  61     }
  62     *_stmt = mStatement;
  63     return SQLITE_OK;
  64   }
  65
  66   operator BindingParamsArray*() const { return mParamsArray; }
  67
  68   /**
  69    * NULLs out our sqlite3_stmt (it is held by the owner) after reseting it and
  70    * clear all bindings to it.  This is expected to occur on the async thread.
  71    */
  72   inline void reset() {
  73     MOZ_ASSERT(mStatementOwner, "Must have a statement owner!");
  74     // In the AsyncStatement case we may never have populated mStatement if the
  75     // AsyncExecuteStatements got canceled or a failure occurred in constructing
  76     // the statement.
  77     if (mStatement) {
  78       (void)::sqlite3_reset(mStatement);
  79       (void)::sqlite3_clear_bindings(mStatement);
  80       mStatement = nullptr;
  81
  82       if (!mQueryStatusRecorded) {
  83         mStatementOwner->getOwner()->RecordQueryStatus(SQLITE_OK);
  84       }
  85     }
  86   }
  87
  88   /**
  89    * Indicates if this statement has parameters to be bound before it is
  90    * executed.
  91    *
  92    * @return true if the statement has parameters to bind against, false
  93    *         otherwise.
  94    */
  95   inline bool hasParametersToBeBound() const { return !!mParamsArray; }
  96   /**
  97    * Indicates the number of implicit statements generated by this statement
  98    * requiring a transaction for execution.  For example a single statement
  99    * with N BindingParams will execute N implicit staments.
 100    *
 101    * @return number of statements requiring a transaction for execution.
 102    *
 103    * @note In the case of AsyncStatements this may actually create the
 104    *       statement.
 105    */
 106   inline uint32_t needsTransaction() {
 107     MOZ_ASSERT(!NS_IsMainThread());
 108     // Be sure to use the getSqliteStatement helper, since sqlite3_stmt_readonly
 109     // can only analyze prepared statements and AsyncStatements are prepared
 110     // lazily.
 111     sqlite3_stmt* stmt;
 112     int rc = getSqliteStatement(&stmt);
 113     if (SQLITE_OK != rc || ::sqlite3_stmt_readonly(stmt)) {
 114       return 0;
 115     }
 116     return mParamsArray ? mParamsArray->length() : 1;
 117   }
 118
 119   void MaybeRecordQueryStatus(int srv) {
 120     if (mQueryStatusRecorded || !isErrorCode(srv)) {
 121       return;
 122     }
 123
 124     mStatementOwner->getOwner()->RecordQueryStatus(srv);
 125     mQueryStatusRecorded = true;
 126   }
 127
 128  private:
 129   sqlite3_stmt* mStatement;
 130   RefPtr<BindingParamsArray> mParamsArray;
 131   bool mQueryStatusRecorded;
 132
 133   /**
 134    * We hold onto a reference of the statement's owner so it doesn't get
 135    * destroyed out from under us.
 136    */
 137   nsCOMPtr<StorageBaseStatementInternal> mStatementOwner;
 138 };
 139
 140 }  // namespace storage
 141 }  // namespace mozilla
 142
 143 #endif  // mozStorageStatementData_h