provide a standard api for calculating pin data for a given public key

lib/pins.js

@@ -2,20 +2,44 @@
 
 var Pins = module.exports;
 
-/*
-    takes contents of a pinFile (UTF8 string)
-    and the pin file's name
-    returns an array of of channel ids which are pinned
-
-    throw errors on pin logs with invalid pin data
+/*  Accepts a reference to an object, and...
+    either a string describing which log is being processed (backwards compatibility),
+    or a function which will log the error with all relevant data
 */
-Pins.calculateFromLog = function (pinFile, fileName) {
-    var pins = {};
-    pinFile.split('\n').filter((x)=>(x)).map((l) => JSON.parse(l)).forEach((l) => {
+var createLineHandler = Pins.createLineHandler = function (ref, errorHandler) {
+    var fileName;
+    if (typeof(errorHandler) === 'string') {
+        fileName = errorHandler;
+        errorHandler = function (label, data) {
+            console.error(label, {
+                log: fileName,
+                data: data,
+            });
+        };
+    }
+
+    // passing the reference to an object allows us to overwrite accumulated pins
+    // make sure to get ref.pins as the result
+    // it's a weird API but it's faster than unpinning manually
+    var pins = ref.pins = {};
+    return function (line) {
+        if (!Boolean(line)) { return; }
+
+        var l;
+        try {
+            l = JSON.parse(line);
+        } catch (e) {
+            return void errorHandler('PIN_LINE_PARSE_ERROR', line);
+        }
+
+        if (!Array.isArray(l)) {
+            return void errorHandler('PIN_LINE_NOT_FORMAT_ERROR', l);
+        }
+
         switch (l[0]) {
             case 'RESET': {
-                pins = {};
-                if (l[1] && l[1].length) { l[1].forEach((x) => { pins[x] = 1; }); }
+                pins = ref.pins = {};
+                if (l[1] && l[1].length) { l[1].forEach((x) => { ref.pins[x] = 1; }); }
                 //jshint -W086
                 // fallthrough
             }
@@ -28,16 +52,25 @@ Pins.calculateFromLog = function (pinFile, fileName) {
                 break;
             }
             default:
-                // FIXME logging
-                // TODO write to the error log
-                /* Log.error('CORRUPTED_PIN_LOG', {
-                    line: JSON.stringify(l),
-                    fileName: fileName,
-                }); */
-                console.error(new Error (JSON.stringify(l) + '  ' + fileName));
+                errorHandler("PIN_LINE_UNSUPPORTED_COMMAND", l);
         }
-    });
-    return Object.keys(pins);
+    };
+};
+
+/*
+    takes contents of a pinFile (UTF8 string)
+    and the pin file's name
+    returns an array of of channel ids which are pinned
+
+    throw errors on pin logs with invalid pin data
+*/
+Pins.calculateFromLog = function (pinFile, fileName) {
+    var ref = {};
+    var handler = createLineHandler(ref, fileName);
+
+    pinFile.split('\n').forEach(handler);
+    return Object.keys(ref.pins);
 };
 
 // TODO refactor to include a streaming version for use in rpc.js as well
+