Closes #955, Don't generate bibliography when dragging many items

Default limit set to 50, configurable in the Export pane

chrome/content/zotero/preferences/preferences.xul

@@ -455,6 +455,7 @@ To add a new preference:
 		<preferences>
 			<preference id="pref-export-citePaperJournalArticleURL" name="extensions.zotero.export.citePaperJournalArticleURL" type="bool"/>
 			<preference id="pref-quickCopy-setting" name="extensions.zotero.export.quickCopy.setting" type="string"/>
+			<preference id="pref-quickCopy-dragLimit" name="extensions.zotero.export.quickCopy.dragLimit" type="int"/>
 		</preferences>
 		
 		<groupbox>
@@ -503,6 +504,15 @@ To add a new preference:
 			
 			<separator/>
 			
+			<!-- TODO: localize -->
+			<hbox align="center">
+				<label value="Disable Quick Copy when dragging more than"/>
+				<textbox preference="pref-quickCopy-dragLimit" size="3"/>
+				<label value="items" flex="1"/>
+			</hbox>
+			
+			<separator/>
+			
 			<label id="quickCopy-macWarning" hidden="true" value="&zotero.preferences.quickCopy.macWarning;"/>
 		</groupbox>
 	</prefpane>

chrome/content/zotero/xpcom/itemTreeView.js

@@ -1715,17 +1715,19 @@ Zotero.ItemTreeView.prototype.onDragStart = function (event, transferData, actio
 		}
 		else if (mode.indexOf('bibliography') == 0) {
 			var content = Zotero.QuickCopy.getContentFromItems(items, format, null, event.shiftKey);
-			if (oldMethod) {
+			if (content) {
-				if (content.html) {
+				if (oldMethod) {
-					transferData.data.addDataForFlavour("text/html", content.html);
+					if (content.html) {
+						transferData.data.addDataForFlavour("text/html", content.html);
+					}
+					transferData.data.addDataForFlavour("text/unicode", content.text);
 				}
-				transferData.data.addDataForFlavour("text/unicode", content.text);
+				else {
-			}
+					if (content.html) {
-			else {
+						event.dataTransfer.setData("text/html", content.html);
-				if (content.html) {
+					}
-					event.dataTransfer.setData("text/html", content.html);
+					event.dataTransfer.setData("text/plain", content.text);
 				}
-				event.dataTransfer.setData("text/plain", content.text);
 			}
 		}
 		else {

chrome/content/zotero/xpcom/quickCopy.js

@@ -132,6 +132,11 @@ Zotero.QuickCopy = new function() {
 	 * contain properties 'text' and 'html' is returned.
 	 */
 	function getContentFromItems(items, format, callback, modified) {
+		if (items.length > Zotero.Prefs.get('export.quickCopy.dragLimit')) {
+			Zotero.debug("Skipping quick copy for " + items.length + " items");
+			return false;
+		}
+		
 		var [mode, format] = format.split('=');
 		var [mode, contentType] = mode.split('/');
 		

defaults/preferences/zotero.js

@@ -81,6 +81,7 @@ pref("extensions.zotero.rtfScan.lastInputFile", "");
 pref("extensions.zotero.rtfScan.lastOutputFile", "");
 
 pref("extensions.zotero.export.quickCopy.setting", 'bibliography=http://www.zotero.org/styles/chicago-note');
+pref("extensions.zotero.export.quickCopy.dragLimit", 50);
 
 // Integration settings
 pref("extensions.zotero.integration.port", 50001);