From 1c230592045727263c5f84a86d70ba688e54e99a Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@jermolene.com>
Date: Mon, 16 Sep 2019 12:15:39 +0100
Subject: [PATCH] Dynamic loading/unloading of plugins (#4259)

* First pass at dynamic loading/unloading

* Show warning for changes to plugins containing JS modules

* Use $:/config/RegisterPluginType/* for configuring whether a plugin type is automatically registered

Where "registered" means "the constituent shadows are loaded".

* Fix the info plugin

The previous mechanism re-read all plugin info during startup

* Don't prettify JSON in the plugin library

* Indicate in plugin library whether a plugin requires reloading

* Display the highlighted plugin name in the plugin chooser

And if there's no name field fall back to the part of the title after the final slash.
---
 boot/boot.js                                 | 55 +++++++++++++-----
 core/language/en-GB/ControlPanel.multids     |  1 +
 core/language/en-GB/Misc.multids             |  2 +-
 core/modules/commands/makelibrary.js         |  2 +-
 core/modules/commands/savelibrarytiddlers.js | 10 +++-
 core/modules/startup/info.js                 |  8 ++-
 core/modules/startup/plugins.js              | 59 ++++++++++++++++++++
 core/modules/wiki.js                         | 20 +++++++
 core/ui/ControlPanel/Modals/AddPlugins.tid   |  3 +-
 core/ui/PageTemplate/pluginreloadwarning.tid |  2 +-
 core/wiki/config/RegisterPluginTypes.multids |  7 +++
 11 files changed, 145 insertions(+), 24 deletions(-)
 create mode 100644 core/modules/startup/plugins.js
 create mode 100644 core/wiki/config/RegisterPluginTypes.multids

diff --git a/boot/boot.js b/boot/boot.js
index 82583c594..9f867c48a 100644
--- a/boot/boot.js
+++ b/boot/boot.js
@@ -1237,15 +1237,39 @@ $tw.Wiki = function(options) {
 		return null;
 	};
 
-	// Read plugin info for all plugins
-	this.readPluginInfo = function() {
-		for(var title in tiddlers) {
-			var tiddler = tiddlers[title];
-			if(tiddler.fields.type === "application/json" && tiddler.hasField("plugin-type")) {
-				pluginInfo[tiddler.fields.title] = JSON.parse(tiddler.fields.text);
+	// Get an array of all the currently recognised plugin types
+	this.getPluginTypes = function() {
+		var types = [];
+		$tw.utils.each(pluginTiddlers,function(pluginTiddler) {
+			var pluginType = pluginTiddler.fields["plugin-type"];
+			if(pluginType && types.indexOf(pluginType) === -1) {
+				types.push(pluginType);
 			}
+		});
+		return types;
+	};
 
-		}
+	// Read plugin info for all plugins, or just an array of titles. Returns the number of plugins updated or deleted
+	this.readPluginInfo = function(titles) {
+		var results = {
+			modifiedPlugins: [],
+			deletedPlugins: []
+		};
+		$tw.utils.each(titles || getTiddlerTitles(),function(title) {
+			var tiddler = tiddlers[title];
+			if(tiddler) {
+				if(tiddler.fields.type === "application/json" && tiddler.hasField("plugin-type")) {
+					pluginInfo[tiddler.fields.title] = JSON.parse(tiddler.fields.text);
+					results.modifiedPlugins.push(tiddler.fields.title);
+				}
+			} else {
+				if(pluginInfo[title]) {
+					delete pluginInfo[title];					
+					results.deletedPlugins.push(title);
+				}
+			}
+		});
+		return results;
 	};
 
 	// Get plugin info for a plugin
@@ -1253,14 +1277,15 @@ $tw.Wiki = function(options) {
 		return pluginInfo[title];
 	};
 
-	// Register the plugin tiddlers of a particular type, optionally restricting registration to an array of tiddler titles. Return the array of titles affected
+	// Register the plugin tiddlers of a particular type, or null/undefined for any type, optionally restricting registration to an array of tiddler titles. Return the array of titles affected
 	this.registerPluginTiddlers = function(pluginType,titles) {
 		var self = this,
 			registeredTitles = [],
 			checkTiddler = function(tiddler,title) {
-				if(tiddler && tiddler.fields.type === "application/json" && tiddler.fields["plugin-type"] === pluginType) {
+				if(tiddler && tiddler.fields.type === "application/json" && tiddler.fields["plugin-type"] && (!pluginType || tiddler.fields["plugin-type"] === pluginType)) {
 					var disablingTiddler = self.getTiddler("$:/config/Plugins/Disabled/" + title);
 					if(title === "$:/core" || !disablingTiddler || (disablingTiddler.fields.text || "").trim() !== "yes") {
+						self.unregisterPluginTiddlers(null,[title]); // Unregister the plugin if it's already registered
 						pluginTiddlers.push(tiddler);
 						registeredTitles.push(tiddler.fields.title);
 					}
@@ -1278,19 +1303,19 @@ $tw.Wiki = function(options) {
 		return registeredTitles;
 	};
 
-	// Unregister the plugin tiddlers of a particular type, returning an array of the titles affected
-	this.unregisterPluginTiddlers = function(pluginType) {
+	// Unregister the plugin tiddlers of a particular type, or null/undefined for any type, optionally restricting unregistering to an array of tiddler titles. Returns an array of the titles affected
+	this.unregisterPluginTiddlers = function(pluginType,titles) {
 		var self = this,
-			titles = [];
+			unregisteredTitles = [];
 		// Remove any previous registered plugins of this type
 		for(var t=pluginTiddlers.length-1; t>=0; t--) {
 			var tiddler = pluginTiddlers[t];
-			if(tiddler.fields["plugin-type"] === pluginType) {
-				titles.push(tiddler.fields.title);
+			if(tiddler.fields["plugin-type"] && (!pluginType || tiddler.fields["plugin-type"] === pluginType) && (!titles || titles.indexOf(tiddler.fields.title) !== -1)) {
+				unregisteredTitles.push(tiddler.fields.title);
 				pluginTiddlers.splice(t,1);
 			}
 		}
-		return titles;
+		return unregisteredTitles;
 	};
 
 	// Unpack the currently registered plugins, creating shadow tiddlers for their constituent tiddlers
diff --git a/core/language/en-GB/ControlPanel.multids b/core/language/en-GB/ControlPanel.multids
index faa4d73c5..d1fd8f374 100644
--- a/core/language/en-GB/ControlPanel.multids
+++ b/core/language/en-GB/ControlPanel.multids
@@ -78,6 +78,7 @@ Plugins/NoInfoFound/Hint: No ''"<$text text=<<currentTab>>/>"'' found
 Plugins/NotInstalled/Hint: This plugin is not currently installed
 Plugins/OpenPluginLibrary: open plugin library
 Plugins/ClosePluginLibrary: close plugin library
+Plugins/PluginWillRequireReload: (requires reload)
 Plugins/Plugins/Caption: Plugins
 Plugins/Plugins/Hint: Plugins
 Plugins/Reinstall/Caption: reinstall
diff --git a/core/language/en-GB/Misc.multids b/core/language/en-GB/Misc.multids
index 0f267186e..599b575eb 100644
--- a/core/language/en-GB/Misc.multids
+++ b/core/language/en-GB/Misc.multids
@@ -59,7 +59,7 @@ MissingTiddler/Hint: Missing tiddler "<$text text=<<currentTiddler>>/>" -- click
 No: No
 OfficialPluginLibrary: Official ~TiddlyWiki Plugin Library
 OfficialPluginLibrary/Hint: The official ~TiddlyWiki plugin library at tiddlywiki.com. Plugins, themes and language packs are maintained by the core team.
-PluginReloadWarning: Please save {{$:/core/ui/Buttons/save-wiki}} and reload {{$:/core/ui/Buttons/refresh}} to allow changes to plugins to take effect
+PluginReloadWarning: Please save {{$:/core/ui/Buttons/save-wiki}} and reload {{$:/core/ui/Buttons/refresh}} to allow changes to ~JavaScript plugins to take effect
 RecentChanges/DateFormat: DDth MMM YYYY
 SystemTiddler/Tooltip: This is a system tiddler
 SystemTiddlers/Include/Prompt: Include system tiddlers
diff --git a/core/modules/commands/makelibrary.js b/core/modules/commands/makelibrary.js
index bb149fd16..ce7150f0c 100644
--- a/core/modules/commands/makelibrary.js
+++ b/core/modules/commands/makelibrary.js
@@ -59,7 +59,7 @@ Command.prototype.execute = function() {
 		title: upgradeLibraryTitle,
 		type: "application/json",
 		"plugin-type": "library",
-		"text": JSON.stringify({tiddlers: tiddlers},null,$tw.config.preferences.jsonSpaces)
+		"text": JSON.stringify({tiddlers: tiddlers})
 	};
 	wiki.addTiddler(new $tw.Tiddler(pluginFields));
 	return null;
diff --git a/core/modules/commands/savelibrarytiddlers.js b/core/modules/commands/savelibrarytiddlers.js
index 44feea071..b1874c9b5 100644
--- a/core/modules/commands/savelibrarytiddlers.js
+++ b/core/modules/commands/savelibrarytiddlers.js
@@ -65,10 +65,11 @@ Command.prototype.execute = function() {
 		// Save each JSON file and collect the skinny data
 		var pathname = path.resolve(self.commander.outputPath,basepath + encodeURIComponent(title) + ".json");
 		$tw.utils.createFileDirectories(pathname);
-		fs.writeFileSync(pathname,JSON.stringify(tiddler,null,$tw.config.preferences.jsonSpaces),"utf8");
+		fs.writeFileSync(pathname,JSON.stringify(tiddler),"utf8");
 		// Collect the skinny list data
 		var pluginTiddlers = JSON.parse(tiddler.text),
 			readmeContent = (pluginTiddlers.tiddlers[title + "/readme"] || {}).text,
+			doesContainJavaScript = !!$tw.wiki.doesPluginInfoContainModules(pluginTiddlers),
 			iconTiddler = pluginTiddlers.tiddlers[title + "/icon"] || {},
 			iconType = iconTiddler.type,
 			iconText = iconTiddler.text,
@@ -76,7 +77,12 @@ Command.prototype.execute = function() {
 		if(iconType && iconText) {
 			iconContent = $tw.utils.makeDataUri(iconText,iconType);
 		}
-		skinnyList.push($tw.utils.extend({},tiddler,{text: undefined, readme: readmeContent, icon: iconContent}));
+		skinnyList.push($tw.utils.extend({},tiddler,{
+			text: undefined,
+			readme: readmeContent,
+			"contains-javascript": doesContainJavaScript ? "yes" : "no",
+			icon: iconContent
+		}));
 	});
 	// Save the catalogue tiddler
 	if(skinnyListTitle) {
diff --git a/core/modules/startup/info.js b/core/modules/startup/info.js
index 1ebf568f4..7efaa5b0e 100644
--- a/core/modules/startup/info.js
+++ b/core/modules/startup/info.js
@@ -18,6 +18,8 @@ exports.before = ["startup"];
 exports.after = ["load-modules"];
 exports.synchronous = true;
 
+var TITLE_INFO_PLUGIN = "$:/temp/info-plugin";
+
 exports.startup = function() {
 	// Collect up the info tiddlers
 	var infoTiddlerFields = {};
@@ -32,15 +34,15 @@ exports.startup = function() {
 			});
 		}
 	});
-	// Bake the info tiddlers into a plugin
+	// Bake the info tiddlers into a plugin. We use the non-standard plugin-type "info" because ordinary plugins are only registered asynchronously after being loaded dynamically
 	var fields = {
-		title: "$:/temp/info-plugin",
+		title: TITLE_INFO_PLUGIN,
 		type: "application/json",
 		"plugin-type": "info",
 		text: JSON.stringify({tiddlers: infoTiddlerFields},null,$tw.config.preferences.jsonSpaces)
 	};
 	$tw.wiki.addTiddler(new $tw.Tiddler(fields));
-	$tw.wiki.readPluginInfo();
+	$tw.wiki.readPluginInfo([TITLE_INFO_PLUGIN]);
 	$tw.wiki.registerPluginTiddlers("info");
 	$tw.wiki.unpackPluginTiddlers();
 };
diff --git a/core/modules/startup/plugins.js b/core/modules/startup/plugins.js
new file mode 100644
index 000000000..5dd03bbf1
--- /dev/null
+++ b/core/modules/startup/plugins.js
@@ -0,0 +1,59 @@
+/*\
+title: $:/core/modules/startup/plugins.js
+type: application/javascript
+module-type: startup
+
+Startup logic concerned with managing plugins
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+// Export name and synchronous status
+exports.name = "plugins";
+exports.after = ["load-modules"];
+exports.synchronous = true;
+
+var TITLE_REQUIRE_RELOAD_DUE_TO_PLUGIN_CHANGE = "$:/status/RequireReloadDueToPluginChange";
+
+var PREFIX_CONFIG_REGISTER_PLUGIN_TYPE = "$:/config/RegisterPluginType/";
+
+exports.startup = function() {
+	$tw.wiki.addTiddler({title: TITLE_REQUIRE_RELOAD_DUE_TO_PLUGIN_CHANGE,text: "no"});
+	$tw.wiki.addEventListener("change",function(changes) {
+		var changesToProcess = [],
+			requireReloadDueToPluginChange = false;
+		$tw.utils.each(Object.keys(changes),function(title) {
+			var tiddler = $tw.wiki.getTiddler(title),
+				containsModules = $tw.wiki.doesPluginContainModules(title);
+			if(containsModules) {
+				requireReloadDueToPluginChange = true;
+			} else if(tiddler) {
+				var pluginType = tiddler.fields["plugin-type"];
+				if($tw.wiki.getTiddlerText(PREFIX_CONFIG_REGISTER_PLUGIN_TYPE + (tiddler.fields["plugin-type"] || ""),"no") === "yes") {
+					changesToProcess.push(title);
+				}
+			}
+		});
+		if(requireReloadDueToPluginChange) {
+			$tw.wiki.addTiddler({title: TITLE_REQUIRE_RELOAD_DUE_TO_PLUGIN_CHANGE,text: "yes"});
+		}
+		// Read or delete the plugin info of the changed tiddlers
+		if(changesToProcess.length > 0) {
+			var changes = $tw.wiki.readPluginInfo(changesToProcess);
+			if(changes.modifiedPlugins.length > 0 || changes.deletedPlugins.length > 0) {
+				// (Re-)register any modified plugins
+				$tw.wiki.registerPluginTiddlers(null,changes.modifiedPlugins);
+				// Unregister any deleted plugins
+				$tw.wiki.unregisterPluginTiddlers(null,changes.deletedPlugins);
+				// Unpack the shadow tiddlers
+				$tw.wiki.unpackPluginTiddlers();
+			}
+		}
+	});
+};
+
+})();
diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index a4bc7b650..c531440a3 100755
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -1450,5 +1450,25 @@ exports.invokeUpgraders = function(titles,tiddlers) {
 	return messages;
 };
 
+// Determine whether a plugin by title contains JS modules. 
+exports.doesPluginContainModules = function(title) {
+	return this.doesPluginInfoContainModules(this.getPluginInfo(title) || this.getTiddlerDataCached(title));
+};
+
+// Determine whether a plugin info structure contains JS modules. 
+exports.doesPluginInfoContainModules = function(pluginInfo) {
+	if(pluginInfo) {
+		var foundModule = false;
+		$tw.utils.each(pluginInfo.tiddlers,function(tiddler) {
+			if(tiddler.type === "application/javascript" && $tw.utils.hop(tiddler,"module-type")) {
+				foundModule = true;
+			}
+		});
+		return foundModule;
+	} else {
+		return null;
+	}
+};
+
 })();
 
diff --git a/core/ui/ControlPanel/Modals/AddPlugins.tid b/core/ui/ControlPanel/Modals/AddPlugins.tid
index b7f84a3c6..0fe8af20d 100644
--- a/core/ui/ControlPanel/Modals/AddPlugins.tid
+++ b/core/ui/ControlPanel/Modals/AddPlugins.tid
@@ -7,6 +7,7 @@ subtitle: {{$:/core/images/download-button}} {{$:/language/ControlPanel/Plugins/
 <$list filter="[<assetInfo>get[original-title]get[version]]" variable="installedVersion" emptyMessage="""{{$:/language/ControlPanel/Plugins/Install/Caption}}""">
 {{$:/language/ControlPanel/Plugins/Reinstall/Caption}}
 </$list>
+<$reveal stateTitle=<<assetInfo>> stateField="contains-javascript" type="match" text="yes">{{$:/language/ControlPanel/Plugins/PluginWillRequireReload}}</$reveal>
 </$button>
 \end
 
@@ -35,7 +36,7 @@ $:/state/add-plugin-info/$(connectionTiddler)$/$(assetInfo)$
 </$list>
 </div>
 <div class="tc-plugin-info-chunk">
-<h1><$view tiddler=<<assetInfo>> field="description"/></h1>
+<h1><strong><$text text={{{ [<assetInfo>get[name]] ~[<assetInfo>get[original-title]split[/]last[1]] }}}/></strong>: <$view tiddler=<<assetInfo>> field="description"/></h1>
 <h2><$view tiddler=<<assetInfo>> field="original-title"/></h2>
 <div><em><$view tiddler=<<assetInfo>> field="version"/></em></div>
 </div>
diff --git a/core/ui/PageTemplate/pluginreloadwarning.tid b/core/ui/PageTemplate/pluginreloadwarning.tid
index d7aa21fe4..4ac44ddc9 100644
--- a/core/ui/PageTemplate/pluginreloadwarning.tid
+++ b/core/ui/PageTemplate/pluginreloadwarning.tid
@@ -3,7 +3,7 @@ tags: $:/tags/PageTemplate
 
 \define lingo-base() $:/language/
 
-<$list filter="[has[plugin-type]haschanged[]!plugin-type[import]limit[1]]">
+<$list filter="[{$:/status/RequireReloadDueToPluginChange}match[yes]]">
 
 <$reveal type="nomatch" state="$:/temp/HidePluginWarning" text="yes">
 
diff --git a/core/wiki/config/RegisterPluginTypes.multids b/core/wiki/config/RegisterPluginTypes.multids
new file mode 100644
index 000000000..d2113728b
--- /dev/null
+++ b/core/wiki/config/RegisterPluginTypes.multids
@@ -0,0 +1,7 @@
+title: $:/config/RegisterPluginType/
+
+plugin: yes
+theme: yes
+language: yes
+info: no
+import: no