# HG changeset patch
# User Atul Varma <varmaa@toolness.com>
# Date 1239746539 25200
# Node ID a5e2db06b58d9d60e369e0080a68543e8fa10442
# Parent  b0d5bc990a8043af506eeab4a610461534334769
Initial proof-of-concept of a WebWorkerMapReducer.  Still needs lots of work.

diff -r b0d5bc990a80 -r a5e2db06b58d browser-couch.js
--- a/browser-couch.js	Tue Apr 14 12:50:23 2009 -0700
+++ b/browser-couch.js	Tue Apr 14 15:02:19 2009 -0700
@@ -93,6 +93,57 @@
   }
 };
 
+function WebWorkerMapReducer(numWorkers, Worker) {
+  if (!Worker)
+    Worker = window.Worker;
+
+  var pool = [];
+
+  function MapWorker() {
+    var worker = new Worker('worker-map-reducer.js');
+    var onDone;
+
+    worker.onmessage = function(event) {
+      onDone(event.data);
+    };
+
+    this.map = function MW_map(map, dict, cb) {
+      onDone = cb;
+      worker.postMessage({map: map.toString(), dict: dict});
+    };
+  }
+
+  for (var i = 0; i < numWorkers; i++)
+    pool.push(new MapWorker());
+
+  this.map = function WWMR_map(map, dict, progress, chunkSize, finished) {
+    pool[0].map(map,
+                dict.pickle(),
+                function onDone(mapDict) {
+                  var mapKeys = [];
+                  for (name in mapDict)
+                    mapKeys.push(name);
+                  mapKeys.sort();
+                  finished({dict: mapDict, keys: mapKeys});
+                });
+
+    // TODO:
+
+    // Break up the dict into multiple chunks.
+
+    // Issue each worker a chunk.
+
+    // When a worker is done with a chunk, pass it a new one and call
+    // the progress callback.
+
+    // When there are no more chunks left to pass out, we're done;
+    // merge all the results into a single mapResult and pass it
+    // to the finished() callback.
+  };
+
+  this.reduce = SingleThreadedMapReducer.reduce;
+};
+
 var SingleThreadedMapReducer = {
   map: function STMR_map(map, dict, progress,
                          chunkSize, finished) {
diff -r b0d5bc990a80 -r a5e2db06b58d worker-map-reducer.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/worker-map-reducer.js	Tue Apr 14 15:02:19 2009 -0700
@@ -0,0 +1,24 @@
+function map(func, dict) {
+  var mapDict = {};
+  var currDoc;
+
+  function emit(key, value) {
+    var item = mapDict[key];
+    if (!item)
+      item = mapDict[key] = {keys: [], values: []};
+    item.keys.push(currDoc.id);
+    item.values.push(value);
+  }
+
+  for (key in dict) {
+    currDoc = dict[key];
+    func(currDoc, emit);
+  }
+
+  return mapDict;
+}
+
+onmessage = function(event) {
+  var mapFunc = eval("(" + event.data.map + ")");
+  postMessage(map(mapFunc, event.data.dict));
+};