deterministic revs for IDBCouch

gistfile1.diff

diff --git a/couch.js b/couch.js
index 26fb69e..21a6e82 100644
--- a/couch.js
+++ b/couch.js
@@ -97,6 +97,198 @@ Dual licensed under the MIT and GPL licenses.
 
 // END Math.uuid.js
 
+/**
+*
+*  MD5 (Message-Digest Algorithm)
+*
+*  For original source see http://www.webtoolkit.info/
+*  Download: 15.02.2009 from http://www.webtoolkit.info/javascript-md5.html
+*
+*  Licensed under CC-BY 2.0 License
+*  (http://creativecommons.org/licenses/by/2.0/uk/)
+*
+**/
+
+var Crypto = {};
+(function() {
+  Crypto.MD5 = function(string) {
+
+    function RotateLeft(lValue, iShiftBits) {
+      return (lValue<<iShiftBits) | (lValue>>>(32-iShiftBits));
+    }
+
+    function AddUnsigned(lX,lY) {
+      var lX4,lY4,lX8,lY8,lResult;
+      lX8 = (lX & 0x80000000);
+      lY8 = (lY & 0x80000000);
+      lX4 = (lX & 0x40000000);
+      lY4 = (lY & 0x40000000);
+      lResult = (lX & 0x3FFFFFFF)+(lY & 0x3FFFFFFF);
+      if (lX4 & lY4) {
+        return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
+      }
+      if (lX4 | lY4) {
+        if (lResult & 0x40000000) {
+          return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
+        } else {
+          return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
+        }
+      } else {
+        return (lResult ^ lX8 ^ lY8);
+      }
+    }
+
+    function F(x,y,z) { return (x & y) | ((~x) & z); }
+    function G(x,y,z) { return (x & z) | (y & (~z)); }
+    function H(x,y,z) { return (x ^ y ^ z); }
+    function I(x,y,z) { return (y ^ (x | (~z))); }
+
+    function FF(a,b,c,d,x,s,ac) {
+      a = AddUnsigned(a, AddUnsigned(AddUnsigned(F(b, c, d), x), ac));
+      return AddUnsigned(RotateLeft(a, s), b);
+    };
+
+    function GG(a,b,c,d,x,s,ac) {
+      a = AddUnsigned(a, AddUnsigned(AddUnsigned(G(b, c, d), x), ac));
+      return AddUnsigned(RotateLeft(a, s), b);
+    };
+
+    function HH(a,b,c,d,x,s,ac) {
+      a = AddUnsigned(a, AddUnsigned(AddUnsigned(H(b, c, d), x), ac));
+      return AddUnsigned(RotateLeft(a, s), b);
+    };
+
+    function II(a,b,c,d,x,s,ac) {
+      a = AddUnsigned(a, AddUnsigned(AddUnsigned(I(b, c, d), x), ac));
+      return AddUnsigned(RotateLeft(a, s), b);
+    };
+
+    function ConvertToWordArray(string) {
+      var lWordCount;
+      var lMessageLength = string.length;
+      var lNumberOfWords_temp1=lMessageLength + 8;
+      var lNumberOfWords_temp2=(lNumberOfWords_temp1-(lNumberOfWords_temp1 % 64))/64;
+      var lNumberOfWords = (lNumberOfWords_temp2+1)*16;
+      var lWordArray=Array(lNumberOfWords-1);
+      var lBytePosition = 0;
+      var lByteCount = 0;
+      while ( lByteCount < lMessageLength ) {
+        lWordCount = (lByteCount-(lByteCount % 4))/4;
+        lBytePosition = (lByteCount % 4)*8;
+        lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount)<<lBytePosition));
+        lByteCount++;
+      }
+      lWordCount = (lByteCount-(lByteCount % 4))/4;
+      lBytePosition = (lByteCount % 4)*8;
+      lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80<<lBytePosition);
+      lWordArray[lNumberOfWords-2] = lMessageLength<<3;
+      lWordArray[lNumberOfWords-1] = lMessageLength>>>29;
+      return lWordArray;
+    };
+
+    function WordToHex(lValue) {
+      var WordToHexValue="",WordToHexValue_temp="",lByte,lCount;
+      for (lCount = 0;lCount<=3;lCount++) {
+        lByte = (lValue>>>(lCount*8)) & 255;
+        WordToHexValue_temp = "0" + lByte.toString(16);
+        WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length-2,2);
+      }
+      return WordToHexValue;
+    };
+
+    //**	function Utf8Encode(string) removed. Aready defined in pidcrypt_utils.js
+
+    var x=Array();
+    var k,AA,BB,CC,DD,a,b,c,d;
+    var S11=7, S12=12, S13=17, S14=22;
+    var S21=5, S22=9 , S23=14, S24=20;
+    var S31=4, S32=11, S33=16, S34=23;
+    var S41=6, S42=10, S43=15, S44=21;
+
+    //	string = Utf8Encode(string); #function call removed
+
+    x = ConvertToWordArray(string);
+
+    a = 0x67452301; b = 0xEFCDAB89; c = 0x98BADCFE; d = 0x10325476;
+
+    for (k=0;k<x.length;k+=16) {
+      AA=a; BB=b; CC=c; DD=d;
+      a=FF(a,b,c,d,x[k+0], S11,0xD76AA478);
+      d=FF(d,a,b,c,x[k+1], S12,0xE8C7B756);
+      c=FF(c,d,a,b,x[k+2], S13,0x242070DB);
+      b=FF(b,c,d,a,x[k+3], S14,0xC1BDCEEE);
+      a=FF(a,b,c,d,x[k+4], S11,0xF57C0FAF);
+      d=FF(d,a,b,c,x[k+5], S12,0x4787C62A);
+      c=FF(c,d,a,b,x[k+6], S13,0xA8304613);
+      b=FF(b,c,d,a,x[k+7], S14,0xFD469501);
+      a=FF(a,b,c,d,x[k+8], S11,0x698098D8);
+      d=FF(d,a,b,c,x[k+9], S12,0x8B44F7AF);
+      c=FF(c,d,a,b,x[k+10],S13,0xFFFF5BB1);
+      b=FF(b,c,d,a,x[k+11],S14,0x895CD7BE);
+      a=FF(a,b,c,d,x[k+12],S11,0x6B901122);
+      d=FF(d,a,b,c,x[k+13],S12,0xFD987193);
+      c=FF(c,d,a,b,x[k+14],S13,0xA679438E);
+      b=FF(b,c,d,a,x[k+15],S14,0x49B40821);
+      a=GG(a,b,c,d,x[k+1], S21,0xF61E2562);
+      d=GG(d,a,b,c,x[k+6], S22,0xC040B340);
+      c=GG(c,d,a,b,x[k+11],S23,0x265E5A51);
+      b=GG(b,c,d,a,x[k+0], S24,0xE9B6C7AA);
+      a=GG(a,b,c,d,x[k+5], S21,0xD62F105D);
+      d=GG(d,a,b,c,x[k+10],S22,0x2441453);
+      c=GG(c,d,a,b,x[k+15],S23,0xD8A1E681);
+      b=GG(b,c,d,a,x[k+4], S24,0xE7D3FBC8);
+      a=GG(a,b,c,d,x[k+9], S21,0x21E1CDE6);
+      d=GG(d,a,b,c,x[k+14],S22,0xC33707D6);
+      c=GG(c,d,a,b,x[k+3], S23,0xF4D50D87);
+      b=GG(b,c,d,a,x[k+8], S24,0x455A14ED);
+      a=GG(a,b,c,d,x[k+13],S21,0xA9E3E905);
+      d=GG(d,a,b,c,x[k+2], S22,0xFCEFA3F8);
+      c=GG(c,d,a,b,x[k+7], S23,0x676F02D9);
+      b=GG(b,c,d,a,x[k+12],S24,0x8D2A4C8A);
+      a=HH(a,b,c,d,x[k+5], S31,0xFFFA3942);
+      d=HH(d,a,b,c,x[k+8], S32,0x8771F681);
+      c=HH(c,d,a,b,x[k+11],S33,0x6D9D6122);
+      b=HH(b,c,d,a,x[k+14],S34,0xFDE5380C);
+      a=HH(a,b,c,d,x[k+1], S31,0xA4BEEA44);
+      d=HH(d,a,b,c,x[k+4], S32,0x4BDECFA9);
+      c=HH(c,d,a,b,x[k+7], S33,0xF6BB4B60);
+      b=HH(b,c,d,a,x[k+10],S34,0xBEBFBC70);
+      a=HH(a,b,c,d,x[k+13],S31,0x289B7EC6);
+      d=HH(d,a,b,c,x[k+0], S32,0xEAA127FA);
+      c=HH(c,d,a,b,x[k+3], S33,0xD4EF3085);
+      b=HH(b,c,d,a,x[k+6], S34,0x4881D05);
+      a=HH(a,b,c,d,x[k+9], S31,0xD9D4D039);
+      d=HH(d,a,b,c,x[k+12],S32,0xE6DB99E5);
+      c=HH(c,d,a,b,x[k+15],S33,0x1FA27CF8);
+      b=HH(b,c,d,a,x[k+2], S34,0xC4AC5665);
+      a=II(a,b,c,d,x[k+0], S41,0xF4292244);
+      d=II(d,a,b,c,x[k+7], S42,0x432AFF97);
+      c=II(c,d,a,b,x[k+14],S43,0xAB9423A7);
+      b=II(b,c,d,a,x[k+5], S44,0xFC93A039);
+      a=II(a,b,c,d,x[k+12],S41,0x655B59C3);
+      d=II(d,a,b,c,x[k+3], S42,0x8F0CCC92);
+      c=II(c,d,a,b,x[k+10],S43,0xFFEFF47D);
+      b=II(b,c,d,a,x[k+1], S44,0x85845DD1);
+      a=II(a,b,c,d,x[k+8], S41,0x6FA87E4F);
+      d=II(d,a,b,c,x[k+15],S42,0xFE2CE6E0);
+      c=II(c,d,a,b,x[k+6], S43,0xA3014314);
+      b=II(b,c,d,a,x[k+13],S44,0x4E0811A1);
+      a=II(a,b,c,d,x[k+4], S41,0xF7537E82);
+      d=II(d,a,b,c,x[k+11],S42,0xBD3AF235);
+      c=II(c,d,a,b,x[k+2], S43,0x2AD7D2BB);
+      b=II(b,c,d,a,x[k+9], S44,0xEB86D391);
+      a=AddUnsigned(a,AA);
+      b=AddUnsigned(b,BB);
+      c=AddUnsigned(c,CC);
+      d=AddUnsigned(d,DD);
+    }
+    var temp = WordToHex(a)+WordToHex(b)+WordToHex(c)+WordToHex(d);
+    return temp.toLowerCase();
+  }
+})();
+
+// END Crypto.md5.js
+
 // Begin request *requires jQuery*
 
 var ajax = function (options, callback) {
@@ -161,6 +353,33 @@ var getNewSequence = function (transaction, couch, callback) {
   }
 }
 
+var getNewRevision = function (doc, oldRevPos) {
+  oldRevPos = (oldRevPos && oldRevPos.split('-')) || [0, ''];
+  var oldPos = Number(oldRevPos[0]);
+  var oldRev = oldRevPos[1];
+
+  var newPos = oldPos + 1;
+
+  // First clear metadata from the doc, leaving only the "body".
+  var metadata = {};
+  for (var key in doc) {
+    if (key && key[0] == '_') {
+      metadata[key] = doc[key];
+      delete(doc[key]);
+    }
+  }
+
+  // TODO: make this match CouchDB using BERTS stuff
+  var newRev = Crypto.MD5(JSON.stringify(doc));
+
+  // Restore the doc so no one hates us
+  for (var key in metadata) {
+    doc[key] = metadata[key];
+  }
+
+  return '-'.join([newPos, newRev]);
+}
+
 var viewQuery = function (objectStore, options) {
   var range;
   var request;
@@ -224,9 +443,6 @@ var makeCouch = function (db, documentStore, sequenceIndex, opts) {
     if (!doc._id) doc._id = Math.uuid();
     if (typeof options.newEdits === 'undefined') options.newEdits = true;
     if (couch.docToSeq[doc._id]) {
-      if (!doc._rev) {
-        options.error({code:413, message:"Update conflict, no revision information"});
-      }
       if (!transaction) {
         transaction = db.transaction(["document-store", "sequence-index"], IDBTransaction.READ_WRITE);
         var bulk = false;
@@ -237,13 +453,13 @@ var makeCouch = function (db, documentStore, sequenceIndex, opts) {
       request.onsuccess = function (event) {
         var prevDocCursor = event.target.result;
         var prev = event.target.result.value;
-        if ((prev._rev !== doc._rev) && options.newEdits) {
-          options.error("Conflict error, revision does not match.")
+        if ((prev._rev !== doc._rev && !prev._deleted) && options.newEdits) {
+          options.error({code:413, "Conflict error, revision does not match."})
           return;
         }
         getNewSequence(transaction, couch, function (seq) {
           if (!options.newEdits) {
-            var rev = Math.uuid(); 
+            var rev = getNewRevision(doc, prev._rev);
           } else {
             var rev = doc._rev;
           }
@@ -291,7 +507,7 @@ var makeCouch = function (db, documentStore, sequenceIndex, opts) {
       } else {var bulk = true}
       
       getNewSequence(transaction, couch, function (seq) {
-        doc._rev = Math.uuid();
+        doc._rev = getNewRevision(doc);
         transaction.objectStore("sequence-index").add({seq:seq, id:doc._id, rev:doc._rev});
         transaction.objectStore("document-store").add(doc);
         if (!bulk) {