Add initial SQLCipher support

Add some basic initial support for SQLCipher. Note that this is more of
a POC than a final implementation.

This commit adds an option called 'sqlcipher' to the cmake and qmake
projects which - when enabled - replaces the default SQLite3 include and
library files by their SQLCipher counter-parts. Especially on MacOS X
there might be some more work required in finding the correct include
paths. The SQLCipher library supports unencrypted databases, too, so
even if the option is enabled the program behaves like before. You can
see the difference, though, in the About Dialog where the SQLite version
string will say 'SQLCipher version xy'.

When the sqlcipher option is enabled and you try to open a file which is
neither a project file nor a normal SQLite3 database it is assumed now
that the file is an encypted database. There is no way to tell between
an invalid file and an encypted file, so in both cases a password dialog
pops up. When the correct password and page size are entered the file is
opened and can be edited like any other database before.

Creating encrypted databases isn't supported yet. So for testing you
need to fall back to the sqlcipher command line tool.

See issue #12.

CMakeLists.txt

@@ -29,7 +29,7 @@ endif()
 set(SQLB_HDR
 	src/gen_version.h
 	src/sqlitetypes.h
-    src/csvparser.h
+	src/csvparser.h
 	src/grammar/sqlite3TokenTypes.hpp
 	src/grammar/Sqlite3Lexer.hpp
 	src/grammar/Sqlite3Parser.hpp
@@ -54,6 +54,7 @@ set(SQLB_MOC_HDR
 	src/sqltextedit.h
 	src/DbStructureModel.h
 	src/Application.h
+	src/sqlite.h
 )
 
 set(SQLB_SRC
@@ -179,13 +180,21 @@ if(APPLE)
 	add_definitions(-DCHECKNEWVERSION)
 endif(APPLE)
 
+# SQLCipher option
+if(sqlcipher)
+	add_definitions(-DSQLCIPHER)
+	set(LIBSQLITE_NAME sqlcipher)
+else(sqlcipher)
+	set(LIBSQLITE_NAME sqlite3)
+endif(sqlcipher)
+
 # add extra library path for MacOS and FreeBSD
 set(EXTRAPATH APPLE OR ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
 if(EXTRAPATH) 
-	find_library(LIBSQLITE sqlite3 HINTS /usr/local/lib /usr/local/opt/sqlite/lib)
+	find_library(LIBSQLITE ${LIBSQLITE_NAME} HINTS /usr/local/lib /usr/local/opt/sqlite/lib)
 	set(ADDITIONAL_INCLUDE_PATHS /usr/local/include /usr/local/opt/sqlite/include)
 else(EXTRAPATH)
-	find_library(LIBSQLITE sqlite3)
+	find_library(LIBSQLITE ${LIBSQLITE_NAME})
 endif(EXTRAPATH)
 
 include_directories(

src/AboutDialog.cpp

@@ -1,7 +1,7 @@
 #include "AboutDialog.h"
 #include "ui_AboutDialog.h"
 #include "gen_version.h"
-#include <sqlite3.h>
+#include "sqlite.h"
 
 AboutDialog::AboutDialog(QWidget *parent) :
     QDialog(parent),
@@ -12,7 +12,11 @@ AboutDialog::AboutDialog(QWidget *parent) :
 
     ui->label_version->setText(ui->label_version->text() + " " + APP_VERSION);
     ui->label_versionqt->setText(ui->label_versionqt->text() + " " + QT_VERSION_STR);
+#ifdef SQLCIPHER
+    ui->label_versionsqlite->setText(ui->label_versionsqlite->text().replace("SQLite", "SQLCipher") + " " + SQLITE_VERSION);
+#else
     ui->label_versionsqlite->setText(ui->label_versionsqlite->text() + " " + SQLITE_VERSION);
+#endif
 }
 
 AboutDialog::~AboutDialog()

src/ExportCsvDialog.cpp

@@ -3,12 +3,12 @@
 #include "sqlitedb.h"
 #include "PreferencesDialog.h"
 #include "sqlitetablemodel.h"
+#include "sqlite.h"
 
 #include <QFile>
 #include <QTextStream>
 #include <QMessageBox>
 #include <QFileDialog>
-#include <sqlite3.h>
 
 ExportCsvDialog::ExportCsvDialog(DBBrowserDB* db, QWidget* parent, const QString& query, const QString& selection)
     : QDialog(parent),

src/ImportCsvDialog.cpp

@@ -2,6 +2,7 @@
 #include "ui_ImportCsvDialog.h"
 #include "sqlitedb.h"
 #include "csvparser.h"
+#include "sqlite.h"
 
 #include <QMessageBox>
 #include <QProgressDialog>
@@ -10,7 +11,6 @@
 #include <QTextCodec>
 #include <QCompleter>
 #include <QComboBox>
-#include <sqlite3.h>
 #include <QFile>
 #include <QTextStream>
 #include <QSettings>

src/MainWindow.cpp

@@ -15,6 +15,7 @@
 #include "VacuumDialog.h"
 #include "DbStructureModel.h"
 #include "gen_version.h"
+#include "sqlite.h"
 
 #include <QFileDialog>
 #include <QFile>
@@ -28,7 +29,6 @@
 #include <QScrollBar>
 #include <QSortFilterProxyModel>
 #include <QElapsedTimer>
-#include <sqlite3.h>
 #include <QNetworkRequest>
 #include <QNetworkReply>
 #include <QNetworkAccessManager>
@@ -195,23 +195,30 @@ bool MainWindow::fileOpen(const QString& fileName, bool dontAddToRecentFiles)
     if(QFile::exists(wFile) )
     {
         fileClose();
-        if(db.open(wFile))
+        // Try opening it as a project file first
+        if(loadProject(wFile))
         {
-            statusEncodingLabel->setText(db.getPragma("encoding"));
-            setCurrentFile(wFile);
-            if(!dontAddToRecentFiles)
-                addToRecentFilesMenu(wFile);
             retval = true;
         } else {
-            // Failed opening file; so it might be a project file instead
-            return loadProject(wFile);
+            // No project file; so it should be a database file
+            if(db.open(wFile))
+            {
+                statusEncodingLabel->setText(db.getPragma("encoding"));
+                setCurrentFile(wFile);
+                if(!dontAddToRecentFiles)
+                    addToRecentFilesMenu(wFile);
+                openSqlTab(true);
+                retval = true;
+            } else {
+                QMessageBox::warning(this, qApp->applicationName(), tr("Invalid file format."));
+                return false;
+            }
         }
         loadExtensionsFromSettings();
         populateStructure();
         resetBrowser();
         if(ui->mainTab->currentIndex() == 2)
             loadPragmas();
-        openSqlTab(true);
     }
 
     return retval;
@@ -1749,10 +1756,7 @@ bool MainWindow::loadProject(QString filename)
         xml.readNext();     // token == QXmlStreamReader::StartDocument
         xml.readNext();     // name == sqlb_project
         if(xml.name() != "sqlb_project")
-        {
-            QMessageBox::warning(this, qApp->applicationName(), tr("Invalid file format."));
             return false;
-        }
 
         addToRecentFilesMenu(filename);
 

src/sqlite.h

@@ -0,0 +1,12 @@
+#ifndef SQLITE_H
+#define SQLITE_H
+
+#ifdef SQLCIPHER
+    #define SQLITE_TEMP_STORE 2
+    #define SQLITE_HAS_CODEC
+    #include <sqlcipher/sqlite3.h>
+#else
+    #include <sqlite3.h>
+#endif
+
+#endif

src/sqlitedb.cpp

@@ -1,5 +1,6 @@
 #include "sqlitedb.h"
 #include "sqlitetablemodel.h"
+#include "sqlite.h"
 
 #include <QFile>
 #include <QMessageBox>
@@ -7,7 +8,7 @@
 #include <QApplication>
 #include <QSettings>
 #include <QDebug>
-#include <sqlite3.h>
+#include <QInputDialog>
 
 // collation callbacks
 int collCompare(void* /*pArg*/, int /*eTextRepA*/, const void* sA, int /*eTextRepB*/, const void* sB)
@@ -43,32 +44,62 @@ bool DBBrowserDB::getDirty() const
     return !savepointList.empty();
 }
 
-bool DBBrowserDB::open ( const QString & db)
+bool DBBrowserDB::open(const QString& db)
 {
     bool ok=false;
     int  err;
 
     if (isOpen()) close();
 
-    //try to verify the SQLite version 3 file header
-    QFile dbfile(db);
-    if ( dbfile.open( QIODevice::ReadOnly ) ) {
-        char buffer[16+1];
-        dbfile.readLine(buffer, 16);
-        QString contents = QString(buffer);
-        dbfile.close();
-        if (!contents.startsWith("SQLite format 3")) {
-            lastErrorMessage = QObject::tr("File is not a SQLite 3 database");
-            return false;
-        }
-    } else {
-        lastErrorMessage = QObject::tr("File could not be read");
+    lastErrorMessage = QObject::tr("no error");
+
+    // Open database file
+    if(sqlite3_open_v2(db.toUtf8(), &_db, SQLITE_OPEN_READWRITE, NULL) != SQLITE_OK)
+    {
+        lastErrorMessage = QString::fromUtf8((const char*)sqlite3_errmsg(_db));
         return false;
     }
 
-    lastErrorMessage = QObject::tr("no error");
-
-    err = sqlite3_open_v2(db.toUtf8(), &_db, SQLITE_OPEN_READWRITE, NULL);
+    // Try reading from database
+    bool done = false;
+    do
+    {
+        QString statement = "SELECT COUNT(*) FROM sqlite_master;";
+        QByteArray utf8Statement = statement.toUtf8();
+        sqlite3_stmt* vm;
+        const char* tail;
+        err = sqlite3_prepare_v2(_db, utf8Statement, utf8Statement.length(), &vm, &tail);
+        if(sqlite3_step(vm) != SQLITE_ROW)
+        {
+#ifdef SQLCIPHER
+            QString pass = QInputDialog::getText(0, qApp->applicationName(),
+                                                 QObject::tr("Couldn't read from database file. This means it is either not a valid SQLite3 "
+                                                             "database or it is encrypted.\nIn the latter case you can provide a passphrase to open the file. Note"
+                                                             "that only databases encrypted using SQLCipher are supported."));
+            if(pass.isEmpty())
+            {
+                sqlite3_close(_db);
+                _db = 0;
+                return false;
+            } else {
+                int pagesize = QInputDialog::getInt(0, qApp->applicationName(),
+                                                    QObject::tr("If the database has been encrypted using a different page size than normally (i.e. 1024 bytes) this "
+                                                                "value is required, too."),
+                                                    1024, 0);
+                if(pagesize == 0) pagesize = 1024;
+                sqlite3_key(_db, pass.toUtf8(), pass.toUtf8().length());
+                sqlite3_exec(_db, QString("PRAGMA cipher_page_size = %1;").arg(pagesize).toUtf8(), NULL, NULL, NULL);
+            }
+#else
+            sqlite3_close(_db);
+            _db = 0;
+            return false;
+#endif
+        } else {
+            done = true;
+        }
+        sqlite3_finalize(vm);
+    } while(!done);
 
     // register collation callback
     sqlite3_collation_needed(_db, NULL, collation_needed);

src/sqlitetablemodel.cpp

@@ -1,10 +1,10 @@
 #include "sqlitetablemodel.h"
 #include "sqlitedb.h"
+#include "sqlite.h"
 
 #include <QDebug>
 #include <QMessageBox>
 #include <QApplication>
-#include <sqlite3.h>
 
 SqliteTableModel::SqliteTableModel(QObject* parent, DBBrowserDB* db, size_t chunkSize)
     : QAbstractTableModel(parent)

src/src.pro

@@ -42,7 +42,8 @@ HEADERS += \
     SqlExecutionArea.h \
     VacuumDialog.h \
     DbStructureModel.h \
-    Application.h
+    Application.h \
+    sqlite.h
 
 SOURCES += \
     sqlitedb.cpp \
@@ -88,6 +89,13 @@ TRANSLATIONS += \
     translations/sqlb_fr.ts \
     translations/sqlb_ru.ts
 
+CONFIG(sqlcipher) {
+	QMAKE_CXXFLAGS += -DENABLE_SQLCIPHER
+	LIBS += -lsqlcipher
+} else {
+	LIBS += -lsqlite3
+}
+
 LIBPATH_QHEXEDIT=$$PWD/../libs/qhexedit
 LIBPATH_ANTLR=$$PWD/../libs/antlr-2.7.7
 LIBPATH_QCUSTOMPLOT=$$PWD/../libs/qcustomplot-source
@@ -121,7 +129,7 @@ mac {
 
 UI_DIR = .ui
 INCLUDEPATH += $$PWD/../libs/antlr-2.7.7 $$PWD/../libs/qhexedit $$PWD/../libs/qcustomplot-source $$PWD/..
-LIBS += -L$$LIBPATH_QHEXEDIT -L$$LIBPATH_ANTLR -L$$LIBPATH_QCUSTOMPLOT -lantlr -lqhexedit -lqcustomplot -lsqlite3
+LIBS += -L$$LIBPATH_QHEXEDIT -L$$LIBPATH_ANTLR -L$$LIBPATH_QCUSTOMPLOT -lantlr -lqhexedit -lqcustomplot
 DEPENDPATH += $$PWD/../libs/antlr-2.7.7 $$PWD/../libs/qhexedit $$PWD/../libs/qcustomplot-source
 
 # Rules for creating/updating {ts|qm}-files