From 516ff44789aa892e6bef9764ff0adcfa55521721 Mon Sep 17 00:00:00 2001
From: Martin Kleusberg <mkleusberg@gmail.com>
Date: Fri, 1 Sep 2017 09:57:44 +0200
Subject: [PATCH] dbhub: Redownload database if local copy has been deleted

See issue #1111.
---
 src/RemoteDatabase.cpp | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/RemoteDatabase.cpp b/src/RemoteDatabase.cpp
index d33be2b1..3f96fe31 100644
--- a/src/RemoteDatabase.cpp
+++ b/src/RemoteDatabase.cpp
@@ -616,8 +616,32 @@ QString RemoteDatabase::localExists(const QUrl& url, QString identity)
     // is newer, or the local commit id is newer.
     if(local_commit_id == url_commit_id)
     {
-        // Both commit ids are the same. That's the perfect match, so just return the path to the local file
-        return Settings::getValue("remote", "clonedirectory").toString() + "/" + local_file;
+        // Both commit ids are the same. That's the perfect match, so we can build the full path to where the file should be
+        QString full_path = Settings::getValue("remote", "clonedirectory").toString() + "/" + local_file;
+
+        // Check if the database still exists. If so return its path, if not return an empty string to redownload it
+        if(QFile::exists(full_path))
+        {
+            return full_path;
+        } else {
+            // Remove the apparently invalid entry from the local clones database to avoid future lookups and confusions. The file column
+            // should be unique for the entire table because the files are all in the same directory and their names need to be unique because
+            // of this.
+            QString sql = QString("DELETE FROM local WHERE file=?");
+            sqlite3_stmt* stmt;
+            if(sqlite3_prepare_v2(m_dbLocal, sql.toUtf8(), -1, &stmt, 0) != SQLITE_OK)
+                return QString();
+            if(sqlite3_bind_text(stmt, 1, local_file.toUtf8(), local_file.toUtf8().length(), SQLITE_TRANSIENT))
+            {
+                sqlite3_finalize(stmt);
+                return QString();
+            }
+            sqlite3_step(stmt);
+            sqlite3_finalize(stmt);
+
+            // Return empty string to indicate a redownload request
+            return QString();
+        }
     } else {
         // In all the other cases just treat the remote database as a completely new database for now.