Added the basic parts for a plugin loader

node/pluginfw/plugins.js

@@ -0,0 +1,82 @@
+var npm = require("npm/lib/npm.js");
+var readInstalled = require("npm/lib/utils/read-installed.js");
+var relativize = require("npm/lib/utils/relativize.js");
+var readJson = require("npm/lib/utils/read-json.js");
+var path = require("path");
+var async = require("async");
+var fs = require("fs");
+var tsort = require("./tsort");
+
+var PLUGIN_PREFIX = 'pluginomatic_';
+
+exports.getPlugins = function (cb, prefix) {
+  prefix = prefix || PLUGIN_PREFIX;
+
+  // Load list of installed NPM packages, flatten it to a list, and filter out only packages with names that
+  // ../.. and not just .. because current dir is like ETHERPAD_ROOT/node/node_modules (!!!!)
+  var dir = path.resolve(npm.dir, "../..")
+  readInstalled(dir, function (er, data) {
+    var plugins = {};
+    var parts = {};
+    function flatten(deps) {
+      Object.keys(deps).forEach(function (name) {
+        if (name.indexOf(prefix) == 0) {
+          plugins[name] = deps[name];
+	}
+	if (deps[name].dependencies !== undefined)
+	  flatten(deps[name].dependencies);
+      });
+    }
+    flatten([data]);
+
+    // Load plugin metadata pluginomatic.json
+    async.forEach(
+      Object.keys(plugins),
+      function (plugin_name, cb) {
+	fs.readFile(
+	  path.resolve(plugins[plugin_name].path, "pluginomatic.json"),
+          function (er, data) {
+	    plugin = JSON.parse(data);
+	    plugin.package = plugins[plugin_name];
+	    plugins[plugin_name] = plugin;
+	    plugin.parts.forEach(function (part) {
+	      part.plugin = plugin;
+              part.full_name = plugin_name + "." + part.name;
+	      parts[part.full_name] = part;
+            });
+	    cb();
+	  }
+        );
+      },
+      function (err) {
+        cb(err, plugins, exports.sortParts(parts));
+      }
+    );
+  });
+}
+
+exports.partsToParentChildList = function (parts) {
+  var res = [];
+  Object.keys(parts).forEach(function (name) {
+    (parts[name].post || []).forEach(function (child_name)  {
+      res.push([name, child_name]);
+    });
+    (parts[name].pre || []).forEach(function (parent_name)  {
+      res.push([parent_name, name]);
+    });
+    if (!parts[name].pre && !parts[name].post) {
+      res.push([name, ":" + name]); // Include apps with no dependency info
+    }
+  });
+  return res;
+}
+
+exports.sortParts = function(parts) {
+  return tsort(
+    exports.partsToParentChildList(parts)
+  ).filter(
+    function (name) { return parts[name] !== undefined; }
+  ).map(
+    function (name) { return parts[name]; }
+  );
+};