Sqlite: Add update hook and use it to get the last changed id

Sqlite has a function to get the last inserted rowid but very often you
want to get the updated rowid too.

Change-Id: Ie276a5039682813ad16597433996a2959f54d9ba
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/lastchangedrowid.h

@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "sqlitedatabaseinterface.h"
+
+#include <utils/smallstringio.h>
+
+#include <iostream>
+
+namespace Sqlite {
+
+class LastChangedRowId
+{
+public:
+    LastChangedRowId(DatabaseInterface &database,
+                     Utils::SmallStringView databaseName,
+                     Utils::SmallStringView tableName)
+        : database(database)
+        , databaseName(databaseName)
+        , tableName(tableName)
+    {
+        callback = [this](ChangeType, char const *database, char const *table, long long rowId) {
+            if (this->databaseName == database && this->tableName == table)
+                lastRowId = rowId;
+        };
+
+        database.setUpdateHook(callback);
+    }
+
+    ~LastChangedRowId() { database.resetUpdateHook(); }
+
+    long long takeLastRowId()
+    {
+        long long rowId = lastRowId;
+        lastRowId = -1;
+        return rowId;
+    }
+
+public:
+    DatabaseInterface &database;
+    DatabaseInterface::UpdateCallback callback;
+    Utils::SmallStringView databaseName;
+    Utils::SmallStringView tableName;
+    long long lastRowId = -1;
+};
+
+} // namespace Sqlite

src/libs/sqlite/sqlite-lib.pri

@@ -25,6 +25,7 @@ SOURCES += \
     $$PWD/sqlitebasestatement.cpp
 HEADERS += \
     $$PWD/createtablesqlstatementbuilder.h \
+    $$PWD/lastchangedrowid.h \
     $$PWD/sqlitedatabasebackend.h \
     $$PWD/sqlitedatabaseinterface.h \
     $$PWD/sqliteexception.h \

src/libs/sqlite/sqlitedatabase.h

@@ -114,6 +114,13 @@ public:
         m_databaseBackend.walCheckpointFull();
     }
 
+    void setUpdateHook(DatabaseBackend::UpdateCallback &callback)
+    {
+        m_databaseBackend.setUpdateHook(callback);
+    }
+
+    void resetUpdateHook() { m_databaseBackend.resetUpdateHook(); }
+
 private:
     void deferredBegin() override;
     void immediateBegin() override;

src/libs/sqlite/sqlitedatabasebackend.cpp

@@ -344,13 +344,11 @@ int indexOfPragma(Utils::SmallStringView pragma, const Utils::SmallStringView (&
 }
 }
 
-constexpr const Utils::SmallStringView journalModeStrings[] = {
-    "delete",
-    "truncate",
-    "persist",
-    "memory",
-    "wal"
-};
+const Utils::SmallStringView journalModeStrings[] = {"delete",
+                                                     "truncate",
+                                                     "persist",
+                                                     "memory",
+                                                     "wal"};
 
 Utils::SmallStringView DatabaseBackend::journalModeToPragma(JournalMode journalMode)
 {
@@ -367,11 +365,7 @@ JournalMode DatabaseBackend::pragmaToJournalMode(Utils::SmallStringView pragma)
     return static_cast<JournalMode>(index);
 }
 
-constexpr const Utils::SmallStringView textEncodingStrings[] = {
-    "UTF-8",
-    "UTF-16le",
-    "UTF-16be"
-};
+const Utils::SmallStringView textEncodingStrings[] = {"UTF-8", "UTF-16le", "UTF-16be"};
 
 Utils::SmallStringView DatabaseBackend::textEncodingToPragma(TextEncoding textEncoding)
 {
@@ -426,6 +420,29 @@ void DatabaseBackend::walCheckpointFull()
     }
 }
 
+namespace {
+void updateCallback(
+    void *callback, int type, char const *database, char const *table, sqlite3_int64 row)
+{
+    auto &function = *reinterpret_cast<DatabaseBackend::UpdateCallback *>(callback);
+
+    function(static_cast<ChangeType>(type), database, table, row);
+}
+} // namespace
+
+void DatabaseBackend::setUpdateHook(UpdateCallback &callback)
+{
+    if (callback)
+        sqlite3_update_hook(m_databaseHandle, updateCallback, &callback);
+    else
+        sqlite3_update_hook(m_databaseHandle, nullptr, nullptr);
+}
+
+void DatabaseBackend::resetUpdateHook()
+{
+    sqlite3_update_hook(m_databaseHandle, nullptr, nullptr);
+}
+
 void DatabaseBackend::throwExceptionStatic(const char *whatHasHappens)
 {
     throw Exception(whatHasHappens);

src/libs/sqlite/sqlitedatabasebackend.h

@@ -40,6 +40,9 @@ class Database;
 class SQLITE_EXPORT DatabaseBackend
 {
 public:
+    using UpdateCallback
+        = std::function<void(ChangeType type, char const *, char const *, long long)>;
+
     DatabaseBackend(Database &database);
     ~DatabaseBackend();
 
@@ -87,6 +90,9 @@ public:
 
     void walCheckpointFull();
 
+    void setUpdateHook(UpdateCallback &callback);
+    void resetUpdateHook();
+
 protected:
     bool databaseIsOpen() const;
 
@@ -128,7 +134,6 @@ private:
     Database &m_database;
     sqlite3 *m_databaseHandle;
     TextEncoding m_cachedTextEncoding;
-
 };
 
 } // namespace Sqlite

src/libs/sqlite/sqlitedatabaseinterface.h

@@ -25,11 +25,23 @@
 
 #pragma once
 
+#include <utils/smallstringview.h>
+
+#include "sqliteglobal.h"
+
+#include <functional>
+
 namespace Sqlite {
 class DatabaseInterface
 {
 public:
+    using UpdateCallback
+        = std::function<void(ChangeType type, char const *, char const *, long long)>;
+
     virtual void walCheckpointFull() = 0;
+    virtual void execute(Utils::SmallStringView sqlStatement) = 0;
+    virtual void setUpdateHook(UpdateCallback &callback) = 0;
+    virtual void resetUpdateHook() = 0;
 
 protected:
     ~DatabaseInterface() = default;

src/libs/sqlite/sqliteexception.h

@@ -29,6 +29,8 @@
 
 #include <utils/smallstring.h>
 
+#include <iostream>
+
 namespace Sqlite {
 
 class SQLITE_EXPORT Exception

src/libs/sqlite/sqliteglobal.h

@@ -84,4 +84,6 @@ enum TextEncoding : char
 
 };
 
+enum class ChangeType : int { Delete = 9, Insert = 18, Update = 23 };
+
 } // namespace Sqlite