From 8b2f2914de0acfa2ea8ee7cb6406e618e2ea5143 Mon Sep 17 00:00:00 2001
From: Petr Bouianov <petr.bouianov@gmail.com>
Date: Mon, 24 Mar 2014 00:43:19 -0400
Subject: [PATCH] RSync as a Shell method. Missing README and tests

---
 gruntfile.js       |   1 +
 src/hash.js        |  53 +++++++
 src/rsync.js       | 371 +++++++++++++++++++++++++++++++++++++++++++++
 src/shell/shell.js |   3 +
 4 files changed, 428 insertions(+)
 create mode 100644 src/hash.js
 create mode 100644 src/rsync.js

diff --git a/gruntfile.js b/gruntfile.js
index 0aa3f44..2dac592 100644
--- a/gruntfile.js
+++ b/gruntfile.js
@@ -28,6 +28,7 @@ module.exports = function(grunt) {
         'src/shell.js',
         'src/fswatcher.js',
         'src/environment.js',
+        'src/rsync.js',
         'src/providers/**/*.js',
         'src/adapters/**/*.js',
         'src/directory-entry.js',
diff --git a/src/hash.js b/src/hash.js
new file mode 100644
index 0000000..74c146c
--- /dev/null
+++ b/src/hash.js
@@ -0,0 +1,53 @@
+// RSync hashing algorithms
+// Based on node.js Anchor's hash.js
+// Used under MIT License 
+// https://github.com/ttezel/anchor
+
+define(function(require) {
+  require("crypto-js/rollups/md5"); 
+
+  function md5(data) {
+    return CryptoJS.MD5(String.fromCharCode.apply(null, data)).toString();
+  }
+  function weak32(data, prev, start, end) {
+    var a = 0,
+        b = 0,
+        sum = 0,
+        M = 1 << 16;
+
+    if (!prev) {
+      var len = start >= 0 && end >= 0 ? end - start : data.length,
+          i = 0;
+
+        for (; i < len; i++) {
+          a += data[i];
+          b += a;
+        }
+
+        a %= M;
+        b %= M;
+    } else {
+      var k = start,
+          l = end - 1,
+          prev_k = k - 1,
+          prev_l = l - 1,
+          prev_first = data[prev_k],
+          prev_last = data[prev_l],
+          curr_first = data[k],
+          curr_last = data[l];
+      
+      a = (prev.a - prev_first + curr_last) % M
+      b = (prev.b - (prev_l - prev_k + 1) * prev_first + a) % M
+    }
+    return { a: a, b: b, sum: a + b * M };
+  }
+  function weak16(data) {
+    return 0xffff & (data >> 16 ^ data*1009);
+  }
+
+  return {
+    md5: md5,
+    weak16: weak16,
+    weak32: weak32
+  };
+});
diff --git a/src/rsync.js b/src/rsync.js
new file mode 100644
index 0000000..4c5d1e5
--- /dev/null
+++ b/src/rsync.js
@@ -0,0 +1,371 @@
+// RSync Module for Filer
+// Based on the Anchor module for node.js (https://github.com/ttezel/anchor)
+// Used under MIT
+
+define(function(require) {
+  var Path = require('src/path');
+  var async = require('async');
+  var _md5 = require('./hash').md5;
+  var _weak16 = require('./hash').weak16;
+  var _weak32 = require('./hash').weak32;
+  var cache = {};
+  var options;
+
+  function createHashtable(checksums) {
+    var hashtable = {};
+    var len = checksums.length;
+    var i = 0;
+    for (; i < len; i++) {
+      var checksum = checksums[i];
+      var weak16 = _weak16(checksum.weak);
+      if (hashtable[weak16]) {
+        hashtable[weak16].push(checksum);
+      } else {
+        hashtable[weak16] = [checksum];
+      }
+    }
+    return hashtable;
+  }
+
+  function roll(data, checksums, chunkSize) {
+    var results = [];
+    var hashtable = createHashtable(checksums);
+    var length = data.length;
+    var start = 0;
+    var end = chunkSize > length ? length : chunkSize;
+        // Updated when a block matches
+    var lastMatchedEnd = 0;
+        // This gets updated every iteration with the previous weak 32bit hash
+    var prevRollingWeak = null;
+    for (; end <= length; start++, end++) {
+      var weak = _weak32(data, prevRollingWeak, start, end);
+      var weak16 = _weak16(weak.sum);
+      var match = false;
+      prevRollingWeak = weak;
+      if (hashtable[weak16]) {
+        var len = hashtable[weak16].length;
+        var i = 0;
+        for (; i < len; i++) {
+          if (hashtable[weak16][i].weak === weak.sum) {
+            var mightMatch = hashtable[weak16][i];
+            var chunk = data.subarray(start, end);
+            var strong = _md5(chunk);
+            if (mightMatch.strong === strong) {
+              match = mightMatch;
+              break;
+            }
+          }
+        }
+      }
+      if (match) {
+        if(start < lastMatchedEnd) {
+          var d = data.subarray(lastMatchedEnd - 1, end);
+          results.push({
+            data: d,
+            index: match.index
+          });
+        } else if (start - lastMatchedEnd > 0) {
+          var d = data.subarray(lastMatchedEnd, start);
+          results.push({
+            data: d,
+            index: match.index
+          });
+        } else {
+          results.push({
+            index: match.index
+          });
+        }
+        lastMatchedEnd = end;
+      } else if (end === length) {
+        // No match and last block
+        var d = data.subarray(lastMatchedEnd);
+        results.push({
+          data: d
+        });
+      }
+    }
+    return results;
+  }
+
+  function rsync (srcPath, destPath, opts, callback) {
+    var self = this;
+    if(typeof options === 'function') {
+      callback = options;
+      options = {};
+    }
+    opts = opts || {};
+    opts.size = opts.size || 750;
+    options = opts;
+    callback = callback || function() {};
+
+    function getSrcList(path, callback) {
+      var result = [];
+      fs.stat(path, function(err, stats) {
+        if(err) callback(err);
+        if(stats.type === 'DIRECTORY') {
+          fs.readdir(path, function(err, entries) {
+            if(err) {
+              callback(err);
+              return;
+            };
+
+            function getSrcContents(name, callback) {
+              var name = Path.join(path, name);
+              fs.stat(name, function(error, stats) {
+                if(error) {
+                  callback(error);
+                  return;
+                }
+                var entry = { 
+                  path: Path.basename(name),
+                  modified: stats.mtime,
+                  type: stats.type
+                };
+                if(options.recursive && stats.type === 'DIRECTORY') {
+                  getSrcList(Path.join(srcPath, entry.path), function(error, items) {
+                    if(error) {
+                      callback(error);
+                      return;
+                    }
+                    entry.contents = items;
+                    result.push(entry);
+                    callback();
+                  });
+                } else if(stats.type === 'FILE') {
+                    result.push(entry);                
+                    callback();
+                } else {
+                  callback();
+                }              
+              });
+            }
+            
+            async.each(entries, getSrcContents, function(error) {
+              callback(error, result);
+            });
+          });
+        }
+        else{
+          var entry = { 
+            path: Path.basename(path),
+            modified: stats.mtime,
+            type: stats.type
+          };
+          result.push(entry);
+          callback(err, result);
+        }
+      });
+    }
+ 
+    function getChecksums(destPath, srcList, callback){     
+      var result = [];
+      function getDirChecksums(entry, callback) {
+        var item = { path: entry.path };
+        if(options.recursive && entry.type === 'DIRECTORY') {
+          getChecksums(Path.join(destPath, entry.path), entry.contents, function(error, items) {
+            if(error) {
+              callback(error);
+              return;
+            }
+            item.contents = items;
+            result.push(item);
+            callback();
+          });
+        } else if(entry.type === 'FILE'){
+          checksum.call(self, Path.join(destPath, entry.path), function(err, checksums) {
+            if(err) {
+              callback(err);
+              return;
+            }
+            item.checksum = checksums;
+            result.push(item); 
+            callback();               
+          });
+        }
+        else{
+          callback();
+        }           
+      }
+      async.each(srcList, getDirChecksums, function(error) {
+        callback(error, result);
+      });
+    }
+    
+    getSrcList(srcPath, function(err, result){
+      console.log(result);
+      fs.exists(destPath, function(res){
+        self.mkdirp(destPath, function(err){
+          getChecksums(destPath, result, function(err, result){
+            console.log(result);
+            diff.call(self, srcPath, result, function(err, diffs) {
+              console.log(diffs);
+              sync.call(self, destPath, diffs, function(err){
+                callback(err);
+              })
+            });
+          });
+        });
+      });
+    });
+  };
+
+  function checksum (path, callback) {
+    var self = this;
+    fs.readFile(path, function (err, data) {
+      if (!err){
+        // cache file
+        cache[path] = data;  
+      }
+      else if (err && err.code === 'ENOENT'){
+        cache[path] = [];
+      }
+      else {
+        callback(err);
+      }
+      var length = cache[path].length;
+      var incr = options.size;
+      var start = 0;
+      var end = incr > length ? length : incr;
+      var blockIndex = 0;
+      var result = [];
+      while (start < length) {
+        var chunk  = cache[path].subarray(start, end);
+        var weak   = _weak32(chunk).sum;
+        var strong = _md5(chunk);
+        result.push({
+          index: blockIndex,
+          weak: weak,
+          strong: strong
+        });
+        // update slice indices
+        start += incr;
+        end = (end + incr) > length ? length : end + incr;
+        // update block index
+        blockIndex++;
+      }
+      return callback(null, result);
+    });
+  }
+  
+  function diff(path, checksums, callback) {
+    var self = this;
+    if (!checksums.length) 
+      return callback(new Error('attribute does not exist'), null);
+    // roll through the file
+    var diffs = [];
+    fs.stat(path, function(err, stat){
+      if(stat.type ==='DIRECTORY') {
+        async.each(checksums, getDiff, function(err) {
+          callback(err, diffs);
+        }); 
+      }
+      else {
+        fs.readFile(path, function (err, data) {
+          if (err) { return callback(err); }
+          diffs.push({
+            diff: roll(data, checksums[0].checksum, options.size),
+            path: checksums[0].path
+          });
+          callback(err, diffs);
+        });
+      }
+    });
+
+    function getDiff(entry, callback) {
+      if(entry.hasOwnProperty('contents')) {
+        diff.call(self, Path.join(path, entry.path), entry.contents, function(err, stuff) {
+          if(err) {
+            callback(err);
+            return;
+          }
+          diffs.push({
+            path: entry.path,
+            contents: stuff
+          });
+          callback();
+        });
+      } else {
+        fs.readFile(Path.join(path,entry.path), function (err, data) {
+          if (err) { return callback(err); }
+          diffs.push({
+            diff: roll(data, entry.checksum, options.size),
+            path: entry.path
+          });
+          callback(err, diffs);
+        });
+      }
+    }
+  }
+
+  function sync(path, diff, callback) {
+    var self = this;
+
+    function syncEach(entry, callback){ 
+      if(entry.hasOwnProperty('contents')) {
+        sync.call(self, Path.join(path, entry.path), entry.contents, function(err){
+          if(err) {
+            callback(err);
+            return;
+          }
+          callback();
+        });
+      }
+      else {
+        var raw = cache[Path.join(path,entry.path)];
+        var i = 0;
+        var len = entry.diff.length;
+        if(typeof raw === 'undefined')
+          return callback(new Error('must do checksum() first'), null);
+
+        //get slice of raw file from block's index
+        function rawslice(index) {
+          var start = index*options.size;
+          var end = start + options.size > raw.length 
+                  ? raw.length 
+                  : start + options.size;
+          return raw.subarray(start, end);
+        }
+
+        var synced = '';
+        var buf = new Uint8Array();
+        for(; i < len; i++) {
+          var chunk = entry.diff[i];
+          if(typeof chunk.data === 'undefined') { //use slice of original file
+            buf = appendBuffer(buf, rawslice(chunk.index));
+            synced += String.fromCharCode.apply(null, rawslice(chunk.index));
+          } else {
+            buf = appendBuffer(buf, chunk.data);
+            synced += String.fromCharCode.apply(null, chunk.data);
+            if(typeof chunk.index !== 'undefined') {
+              buf = appendBuffer(buf, rawslice(chunk.index));
+              synced += String.fromCharCode.apply(null, rawslice(chunk.index));
+            }
+          }
+        }
+        delete cache[Path.join(path,entry.path)];
+        fs.writeFile(Path.join(path,entry.path), buf, function(err){
+          if(err){
+            callback(err);
+            return;
+          }
+          return callback(null);  
+        })
+        
+      }
+    }
+
+    async.each(diff, syncEach, function(err) {
+      callback(err);
+    }); 
+  }
+
+  function appendBuffer( buffer1, buffer2 ) {
+    var tmp = new Uint8Array( buffer1.byteLength + buffer2.byteLength );
+    tmp.set( new Uint8Array( buffer1 ), 0 );
+    tmp.set( new Uint8Array( buffer2 ), buffer1.byteLength );
+    return tmp;
+  }
+
+  return rsync;
+
+});
diff --git a/src/shell/shell.js b/src/shell/shell.js
index bccd9f8..6f387af 100644
--- a/src/shell/shell.js
+++ b/src/shell/shell.js
@@ -5,6 +5,7 @@ define(function(require) {
   var Errors = require('src/errors');
   var Environment = require('src/shell/environment');
   var async = require('async');
+  var rsync = require('src/rsync');
 
   function Shell(fs, options) {
     options = options || {};
@@ -422,6 +423,8 @@ define(function(require) {
     _mkdirp(path, callback);
   };
 
+  Shell.prototype.rsync = rsync;
+
   return Shell;
 
 });