From 4ee42b87d47ce1d4189ea88e54749d15681bfa6f Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Mon, 22 May 2017 12:04:47 +0200
Subject: [PATCH] make file crypto great again

---
 www/file/file-crypto.js | 58 +++++++++++++++++++++++++----------------
 www/file/main.js        |  2 ++
 2 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/www/file/file-crypto.js b/www/file/file-crypto.js
index cde49759c..c7bd74ea3 100644
--- a/www/file/file-crypto.js
+++ b/www/file/file-crypto.js
@@ -58,14 +58,14 @@ define([
     };
 
     var joinChunks = function (chunks) {
-        return new Uint8Array(chunks.reduce(function (A, B) {
-            return slice(A).concat(slice(B));
-        }, []));
+        return new Blob(chunks);
     };
 
-    var decrypt = function (u8, key, cb) {
-        var fail = function (e) {
-            cb(e || "DECRYPTION_ERROR");
+    var decrypt = function (u8, key, done, progress) {
+        var MAX = u8.length;
+        var _progress = function (offset) {
+            if (typeof(progress) !== 'function') { return; }
+            progress(Math.min(1, offset / MAX));
         };
 
         var nonce = createNonce();
@@ -86,16 +86,18 @@ define([
         try {
             res.metadata = JSON.parse(Nacl.util.encodeUTF8(metaChunk));
         } catch (e) {
-            return fail('E_METADATA_DECRYPTION');
+            return window.setTimeout(function () {
+                done('E_METADATA_DECRYPTION');
+            });
         }
 
         if (!res.metadata) {
             return void setTimeout(function () {
-                cb('NO_METADATA');
+                done('NO_METADATA');
             });
         }
 
-        var takeChunk = function () {
+        var takeChunk = function (cb) {
             var start = i * cypherChunkLength + 2 + metadataLength;
             var end = start + cypherChunkLength;
             i++;
@@ -104,24 +106,36 @@ define([
             // decrypt the chunk
             var plaintext = Nacl.secretbox.open(box, nonce, key);
             increment(nonce);
-            return plaintext;
+
+            if (!plaintext) { return cb('DECRYPTION_ERROR'); }
+
+            _progress(end);
+            cb(void 0, plaintext);
         };
 
         var chunks = [];
-        // decrypt file contents
-        var chunk;
-        for (;i * cypherChunkLength < u8.length;) {
-            chunk = takeChunk();
-            if (!chunk) {
-                return window.setTimeout(fail);
-            }
-            chunks.push(chunk);
-        }
 
-        // send chunks
-        res.content = joinChunks(chunks);
+        var again = function () {
+            takeChunk(function (e, plaintext) {
+                if (e) {
+                    return setTimeout(function () {
+                        done(e);
+                    });
+                }
+                if (plaintext) {
+                    if (i * cypherChunkLength < u8.length) { // not done
+                        chunks.push(plaintext);
+                        return setTimeout(again);
+                    }
+                    chunks.push(plaintext);
+                    res.content = joinChunks(chunks);
+                    return done(void 0, res);
+                }
+                done('UNEXPECTED_ENDING');
+            });
+        };
 
-        cb(void 0, res);
+        again();
     };
 
     // metadata
diff --git a/www/file/main.js b/www/file/main.js
index ada0b50d2..0ce6ecefa 100644
--- a/www/file/main.js
+++ b/www/file/main.js
@@ -273,6 +273,8 @@ define([
                     myDataType = data.metadata.type;
                     Title.updateTitle(title || Title.defaultTitle);
                     Cryptpad.removeLoadingScreen();
+                }, function (progress) {
+                    console.error(progress);
                 });
             });
         }