Revise search plugin install procedure

src/base/search/searchpluginmanager.cpp

@@ -248,60 +248,96 @@ void SearchPluginManager::installPlugin(const QString &source)
     }
 }
 
-void SearchPluginManager::installPlugin_impl(const QString &name, const Path &path)
+void SearchPluginManager::installPlugin_impl(const QString &name, const Path &srcPath)
 {
-    const SearchPluginVersion newVersion = getPluginVersion(path);
+    const SearchPluginVersion incomingVersion = getPluginVersion(srcPath);
     const SearchPluginInfo *plugin = pluginInfo(name);
-    if (plugin && !(plugin->version < newVersion))
+    if (plugin && (plugin->version >= incomingVersion))
     {
-        LogMsg(tr("Plugin already at version %1, which is greater than %2").arg(plugin->version.toString(), newVersion.toString()), Log::INFO);
+        LogMsg(tr("Same or newer version of search plugin is already installed. Plugin name: \"%1\". Current version: %2. Incoming version: %3")
+            .arg(plugin->name, plugin->version.toString(), incomingVersion.toString()), Log::INFO);
         emit pluginUpdateFailed(name, tr("A more recent version of this plugin is already installed."));
         return;
     }
 
-    // Process with install
+    // Proceed to install
     const Path destPath = pluginPath(name);
     const Path backupPath = destPath + u".bak";
-    bool updated = false;
-    if (destPath.exists())
+    const bool hasExistingPlugin = destPath.exists();
+    bool hasBackup = false;
+
+    if (destPath != srcPath)
     {
+        // Plugin is not at the dest path, otherwise there is nothing to do here
+
         // Backup in case install fails
-        Utils::Fs::copyFile(destPath, backupPath);
-        Utils::Fs::removeFile(destPath);
-        updated = true;
+        if (hasExistingPlugin)
+        {
+            hasBackup = Utils::Fs::copyFile(destPath, backupPath);
+            Utils::Fs::removeFile(destPath);
+        }
+
+        // Copy the plugin to dest path
+        if (!Utils::Fs::copyFile(srcPath, destPath))
+        {
+            // Roll back
+            Utils::Fs::removeFile(destPath);
+            if (hasBackup)
+            {
+                // restore backup
+                if (Utils::Fs::copyFile(backupPath, destPath))
+                    Utils::Fs::removeFile(backupPath);
+                else
+                    Utils::Fs::removeFile(destPath);
+            }
+
+            const QString errMsg = tr("Search plugin installation failed.");
+            if (hasExistingPlugin)
+                emit pluginUpdateFailed(name, errMsg);
+            else
+                emit pluginInstallationFailed(name, errMsg);
+
+            return;
+        }
     }
-    // Copy the plugin
-    Utils::Fs::copyFile(path, destPath);
+
     // Update supported plugins
     update();
-    // Check if this was correctly installed
-    if (!m_plugins.contains(name))
+
+    // Check if it was correctly installed
+    if (m_plugins.contains(name))
     {
-        // Remove broken file
-        Utils::Fs::removeFile(destPath);
-        LogMsg(tr("Plugin %1 is not supported.").arg(name), Log::INFO);
-        if (updated)
-        {
-            // restore backup
-            Utils::Fs::copyFile(backupPath, destPath);
+        // installation successful
+        LogMsg(tr("Search plugin has been updated. Plugin name: \"%1\". Version: %2.").arg(name, incomingVersion.toString()), Log::INFO);
+
+        if (hasBackup)
             Utils::Fs::removeFile(backupPath);
-            // Update supported plugins
-            update();
-            emit pluginUpdateFailed(name, tr("Plugin is not supported."));
-        }
-        else
-        {
-            emit pluginInstallationFailed(name, tr("Plugin is not supported."));
-        }
     }
     else
     {
-        // Install was successful, remove backup
-        if (updated)
+        LogMsg(tr("Search plugin installation failed. Plugin name: \"%1\"").arg(name), Log::INFO);
+
+        // Roll back
+        Utils::Fs::removeFile(destPath);
+        if (hasBackup)
         {
-            LogMsg(tr("Plugin %1 has been successfully updated.").arg(name), Log::INFO);
-            Utils::Fs::removeFile(backupPath);
+            // restore backup
+            if (Utils::Fs::copyFile(backupPath, destPath))
+            {
+                Utils::Fs::removeFile(backupPath);
+                update();  // Update supported plugins
+            }
+            else
+            {
+                Utils::Fs::removeFile(destPath);
+            }
         }
+
+        const QString errMsg = tr("Plugin is not supported.");
+        if (hasExistingPlugin)
+            emit pluginUpdateFailed(name, errMsg);
+        else
+            emit pluginInstallationFailed(name, errMsg);
     }
 }
 

src/base/search/searchpluginmanager.h

@@ -112,7 +112,7 @@ class SearchPluginManager final : public QObject
     void update();
     void updateNova();
     void parseVersionInfo(const QByteArray &info);
-    void installPlugin_impl(const QString &name, const Path &path);
+    void installPlugin_impl(const QString &name, const Path &srcPath);
     bool isUpdateNeeded(const QString &pluginName, const SearchPluginVersion &newVersion) const;
 
     void versionInfoDownloadFinished(const Net::DownloadResult &result);