From 1a6c34951b9960efe27b0aab599673f3391642fa Mon Sep 17 00:00:00 2001
From: Martin Kleusberg <mkleusberg@gmail.com>
Date: Sun, 15 Jan 2017 21:10:23 +0100
Subject: [PATCH] Fix error handling in open database procedure

When opening a database fails a proper error message is now shown which
hopefully tells the user what the source of the problem is. Note: this
will only work for newer versions of SQLite.

This requires a bug fix which is included in this commit. The error
message wasn't taken from the correct database handle, so it had nothing
to do with the actual error source. This is fixed by this commit as
well.
---
 src/MainWindow.cpp |  2 +-
 src/sqlitedb.cpp   | 15 +++++++++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/MainWindow.cpp b/src/MainWindow.cpp
index 1fed0ef8..5bf5bbb5 100644
--- a/src/MainWindow.cpp
+++ b/src/MainWindow.cpp
@@ -307,7 +307,7 @@ bool MainWindow::fileOpen(const QString& fileName, bool dontAddToRecentFiles, bo
                     loadPragmas();
                 retval = true;
             } else {
-                QMessageBox::warning(this, qApp->applicationName(), tr("Invalid file format."));
+                QMessageBox::warning(this, qApp->applicationName(), tr("Could not open database file.\nReason: %1").arg(db.lastErrorMessage));
                 return false;
             }
         }
diff --git a/src/sqlitedb.cpp b/src/sqlitedb.cpp
index 0dbad15a..23845c48 100644
--- a/src/sqlitedb.cpp
+++ b/src/sqlitedb.cpp
@@ -93,10 +93,7 @@ bool DBBrowserDB::open(const QString& db, bool readOnly)
     // Get encryption settings for database file
     CipherDialog* cipher = 0;
     if(tryEncryptionSettings(db, &isEncrypted, cipher) == false)
-    {
-        lastErrorMessage = QString::fromUtf8((const char*)sqlite3_errmsg(_db));
         return false;
-    }
 
     // Open database file
     if(sqlite3_open_v2(db.toUtf8(), &_db, readOnly ? SQLITE_OPEN_READONLY : SQLITE_OPEN_READWRITE, NULL) != SQLITE_OK)
@@ -208,6 +205,8 @@ bool DBBrowserDB::attach(const QString& filename, QString attach_as)
 
 bool DBBrowserDB::tryEncryptionSettings(const QString& filename, bool* encrypted, CipherDialog*& cipherSettings)
 {
+    lastErrorMessage = tr("Invalid file format");
+
     // Open database file
     sqlite3* dbHandle;
     if(sqlite3_open_v2(filename.toUtf8(), &dbHandle, SQLITE_OPEN_READWRITE, NULL) != SQLITE_OK)
@@ -222,7 +221,14 @@ bool DBBrowserDB::tryEncryptionSettings(const QString& filename, bool* encrypted
         QByteArray utf8Statement = statement.toUtf8();
         sqlite3_stmt* vm;
         const char* tail;
-        sqlite3_prepare_v2(dbHandle, utf8Statement, utf8Statement.length(), &vm, &tail);
+        int err = sqlite3_prepare_v2(dbHandle, utf8Statement, utf8Statement.length(), &vm, &tail);
+        if(err == SQLITE_BUSY || err == SQLITE_PERM || err == SQLITE_NOMEM || err == SQLITE_IOERR || err == SQLITE_CORRUPT || err == SQLITE_CANTOPEN)
+        {
+            lastErrorMessage = QString::fromUtf8((const char*)sqlite3_errmsg(dbHandle));
+            sqlite3_close(dbHandle);
+            return false;
+        }
+
         if(sqlite3_step(vm) != SQLITE_ROW)
         {
             sqlite3_finalize(vm);
@@ -254,6 +260,7 @@ bool DBBrowserDB::tryEncryptionSettings(const QString& filename, bool* encrypted
                 return false;
             }
 #else
+            lastErrorMessage = QString::fromUtf8((const char*)sqlite3_errmsg(dbHandle));
             sqlite3_close(dbHandle);
             return false;
 #endif