replicate existing pinned.load API correctly

lib/pins.js

@@ -96,11 +96,20 @@ const getSafeKeyFromPath = function (path) {
     return path.replace(/^.*\//, '').replace(/\.ndjson/, '');
 }
 
-Pins.list = function (done, config) {
+Pins.list = function (_done, config) {
     const pinPath = config.pinPath || './data/pins';
     const plan = Plan(config.workers || 5);
     const handler = config.handler || function () {};
 
+    var isDone = false;
+    // ensure that 'done' is only called once
+    // that it calls back asynchronously
+    // and that it sets 'isDone' to true, so that pending processes
+    // know to abort
+    const done = Util.once(Util.both(Util.mkAsync(_done), function () {
+        isDone = true;
+    }));
+
     // TODO externalize this via optional handlers?
     const stats = {
         logs: 0,
@@ -137,29 +146,39 @@ Pins.list = function (done, config) {
                 return void cb(err);
             }
             cb(void 0, list.map(function (item) {
-                return Path.join(path, item);
+                return {
+                    path: Path.join(path, item),
+                    id: item.replace(/\.ndjson$/, ''),
+                };
             }));
         });
     };
 
-    scanDirectory(pinPath, function (err, paths) {
+    scanDirectory(pinPath, function (err, dirs) {
-        if (err) { return; } // XXX
+        if (err) {
-        paths.forEach(function (path) {
+            if (err.code === 'ENOENT') { return void cb(void 0, {}); }
+            return void done(err);
+        }
+        dirs.forEach(function (dir) {
             plan.job(1, function (next) {
-                scanDirectory(path, function (nested_err, nested_paths) {
+                if (isDone) { return void next(); }
-                    if (nested_err) { return; } // XXX
+                scanDirectory(dir.path, function (nested_err, logs) {
+                    if (nested_err) {
+                        return void done(err);
+                    }
                     stats.dirs++;
-                    nested_paths.forEach(function (nested_path) {
+                    logs.forEach(function (log) {
-                        if (!/\.ndjson$/.test(nested_path)) { return; }
+                        if (!/\.ndjson$/.test(log.path)) { return; }
                         plan.job(0, function (next)  {
-                            streamFile(nested_path, function (err, ref) {
+                            if (isDone) { return void next(); }
-                                if (err) { return; } // XXX
+                            streamFile(log.path, function (err, ref) {
+                                if (err) { return void done(err); }
                                 stats.logs++;
 
                                 var set = ref.pins;
                                 for (var item in set) {
+                                    (pinned[item] = pinned[item] || {})[log.id] = 1;
                                     if (!pinned.hasOwnProperty(item)) {
-                                        pinned[item] = true;
                                         stats.pinned++;
                                     }
                                 }