Content merge

src/data/emptySyncContent.js

@@ -1,7 +1,7 @@
 export default () => ({
   id: null,
   type: 'syncContent',
-  contentRevisions: {},
+  historyData: {},
   syncLocationData: {},
   updated: 0,
 });

src/libs/cldiffutils.js

@@ -1,482 +0,0 @@
-import 'clunderscore';
-import DiffMatchPatch from 'diff-match-patch';
-
-var clDiffUtils = {
-  cloneObject: cloneObject,
-  offsetToPatch: offsetToPatch,
-  patchToOffset: patchToOffset,
-  serializeObject: serializeObject,
-  flattenContent: flattenContent,
-  makePatchableText: makePatchableText,
-  restoreDiscussionOffsets: restoreDiscussionOffsets,
-  makeContentChange: makeContentChange,
-  applyContentChanges: applyContentChanges,
-  getTextPatches: getTextPatches,
-  getObjectPatches: getObjectPatches,
-  quickPatch: quickPatch,
-  mergeObjects: mergeObjects,
-  mergeFlattenContent: mergeFlattenContent
-}
-
-var marker = '\uF111\uF222\uF333\uF444'
-var DIFF_DELETE = -1
-var DIFF_INSERT = 1
-var DIFF_EQUAL = 0
-var diffMatchPatch = new DiffMatchPatch() // eslint-disable-line new-cap
-var diffMatchPatchStrict = new DiffMatchPatch() // eslint-disable-line new-cap
-diffMatchPatchStrict.Match_Threshold = 0
-diffMatchPatchStrict.Patch_DeleteThreshold = 0
-var diffMatchPatchPermissive = new DiffMatchPatch() // eslint-disable-line new-cap
-diffMatchPatchPermissive.Match_Distance = 999999999
-
-function cloneObject (obj) {
-  return JSON.parse(JSON.stringify(obj))
-}
-
-function offsetToPatch (text, offset) {
-  var patch = diffMatchPatchPermissive.patch_make(text, [
-    [0, text.slice(0, offset)],
-    [1, marker],
-    [0, text.slice(offset)]
-  ])[0]
-  var diffs = patch.diffs.cl_map(function (diff) {
-    if (!diff[0]) {
-      return diff[1]
-    } else if (diff[1] === marker) {
-      return ''
-    }
-  })
-  return {
-    diffs: diffs,
-    length: patch.length1,
-    start: patch.start1
-  }
-}
-
-function patchToOffset (text, patch) {
-  var markersLength = 0
-  var diffs = patch.diffs.cl_map(function (diff) {
-    if (!diff) {
-      markersLength += marker.length
-      return [1, marker]
-    } else {
-      return [0, diff]
-    }
-  })
-  return diffMatchPatchPermissive.patch_apply([{
-    diffs: diffs,
-    length1: patch.length,
-    length2: patch.length + markersLength,
-    start1: patch.start,
-    start2: patch.start
-  }], text)[0].indexOf(marker)
-}
-
-function flattenObject (obj) {
-  return obj.cl_reduce(function (result, value, key) {
-    result[key] = value[1]
-    return result
-  }, {})
-}
-
-function flattenContent (content) {
-  var result = ({}).cl_extend(content)
-  result.properties = flattenObject(content.properties)
-  result.discussions = flattenObject(content.discussions)
-  result.comments = flattenObject(content.comments)
-  result.text = content.text.cl_reduce(function (text, item) {
-    switch (item.type) {
-      case 'discussion':
-        if (result.discussions[item.id]) {
-          result.discussions[item.id][item.name] = text.length
-        }
-        return text
-      default:
-        return text + item[1]
-    }
-  }, '')
-  return result
-}
-
-function getTextPatches (oldText, newText) {
-  var diffs = diffMatchPatch.diff_main(oldText, newText)
-  diffMatchPatch.diff_cleanupEfficiency(diffs)
-  var patches = []
-  var startOffset = 0
-  diffs.cl_each(function (change) {
-    var changeType = change[0]
-    var changeText = change[1]
-    switch (changeType) {
-      case DIFF_EQUAL:
-        startOffset += changeText.length
-        break
-      case DIFF_DELETE:
-        changeText && patches.push({
-          o: startOffset,
-          d: changeText
-        })
-        break
-      case DIFF_INSERT:
-        changeText && patches.push({
-          o: startOffset,
-          a: changeText
-        })
-        startOffset += changeText.length
-        break
-    }
-  })
-  return patches.length ? patches : undefined
-}
-
-function getObjectPatches (oldObject, newObjects) {
-  var valueHash = Object.create(null)
-  var valueArray = []
-  oldObject = hashObject(oldObject, valueHash, valueArray)
-  newObjects = hashObject(newObjects, valueHash, valueArray)
-  var diffs = diffMatchPatch.diff_main(oldObject, newObjects)
-  var patches = []
-  diffs.cl_each(function (change) {
-    var changeType = change[0]
-    var changeHash = change[1]
-    if (changeType === DIFF_EQUAL) {
-      return
-    }
-    changeHash.split('').cl_each(function (objHash) {
-      var obj = valueArray[objHash.charCodeAt(0)]
-      var patch = {
-        k: obj[0]
-      }
-      patch[changeType === DIFF_DELETE ? 'd' : 'a'] = obj[1]
-      patches.push(patch)
-    })
-  })
-  return patches.length ? patches : undefined
-}
-
-function makePatchableText (content, markerKeys, markerIdxMap) {
-  var markers = []
-  // Sort keys to have predictable marker positions, in case of same offset
-  var discussionKeys = Object.keys(content.discussions).sort()
-  discussionKeys.cl_each(function (discussionId) {
-    function addMarker (offsetName) {
-      var markerKey = discussionId + offsetName
-      if (discussion[offsetName] !== undefined) {
-        var idx = markerIdxMap[markerKey]
-        if (idx === undefined) {
-          idx = markerKeys.length
-          markerIdxMap[markerKey] = idx
-          markerKeys.push({
-            id: discussionId,
-            offsetName: offsetName
-          })
-        }
-        markers.push({
-          idx: idx,
-          offset: discussion[offsetName]
-        })
-      }
-    }
-
-    var discussion = content.discussions[discussionId]
-    if (discussion.offset0 === discussion.offset1) {
-      // Remove discussion offsets if markers are at the same position
-      discussion.offset0 = discussion.offset1 = undefined
-    } else {
-      addMarker('offset0')
-      addMarker('offset1')
-    }
-  })
-
-  var lastOffset = 0
-  var result = ''
-  markers
-    .sort(function (marker1, marker2) {
-      return marker1.offset - marker2.offset
-    })
-    .cl_each(function (marker) {
-      result +=
-        content.text.slice(lastOffset, marker.offset) +
-        String.fromCharCode(0xe000 + marker.idx) // Use a character from the private use area
-      lastOffset = marker.offset
-    })
-  return result + content.text.slice(lastOffset)
-}
-
-function stripDiscussionOffsets (objectMap) {
-  return objectMap.cl_reduce(function (result, object, id) {
-    result[id] = {
-      text: object.text
-    }
-    return result
-  }, {})
-}
-
-function restoreDiscussionOffsets (content, markerKeys) {
-  var len = content.text.length
-  var maxIdx = markerKeys.length
-  for (var i = 0; i < len; i++) {
-    var idx = content.text.charCodeAt(i) - 0xe000
-    if (idx >= 0 && idx < maxIdx) {
-      var markerKey = markerKeys[idx]
-      content.text = content.text.slice(0, i) + content.text.slice(i + 1)
-      var discussion = content.discussions[markerKey.id]
-      if (discussion) {
-        discussion[markerKey.offsetName] = i
-      }
-      i-- // We just removed the current character, we may have multiple markers with same offset
-    }
-  }
-}
-
-function makeContentChange (oldContent, newContent) {
-  var markerKeys = []
-  var markerIdxMap = Object.create(null)
-  var oldText = makePatchableText(oldContent, markerKeys, markerIdxMap)
-  var newText = makePatchableText(newContent, markerKeys, markerIdxMap)
-  var textPatches = getTextPatches(oldText, newText)
-  textPatches && textPatches.cl_each(function (patch) {
-    // If markers are present, replace changeText with an array of text and markers
-    var changeText = patch.a || patch.d
-    var textItems = []
-    var lastItem = ''
-    var len = changeText.length
-    var maxIdx = markerKeys.length
-    for (var i = 0; i < len; i++) {
-      var idx = changeText.charCodeAt(i) - 0xe000
-      if (idx >= 0 && idx < maxIdx) {
-        var markerKey = markerKeys[idx]
-        lastItem.length && textItems.push(lastItem)
-        textItems.push({
-          type: 'discussion',
-          name: markerKey.offsetName,
-          id: markerKey.id
-        })
-        lastItem = ''
-      } else {
-        lastItem += changeText[i]
-      }
-    }
-    if (textItems.length) {
-      lastItem.length && textItems.push(lastItem)
-      if (patch.a) {
-        patch.a = textItems
-      } else {
-        patch.d = textItems
-      }
-    }
-  })
-  var propertiesPatches = getObjectPatches(oldContent.properties, newContent.properties)
-  var discussionsPatches = getObjectPatches(
-    stripDiscussionOffsets(oldContent.discussions),
-    stripDiscussionOffsets(newContent.discussions)
-  )
-  var commentsPatches = getObjectPatches(oldContent.comments, newContent.comments)
-  if (textPatches || propertiesPatches || discussionsPatches || commentsPatches) {
-    return {
-      text: textPatches,
-      properties: propertiesPatches,
-      discussions: discussionsPatches,
-      comments: commentsPatches
-    }
-  }
-}
-
-function applyContentChanges (content, contentChanges, isBackward) {
-  function applyObjectPatches (obj, patches) {
-    if (patches) {
-      patches.cl_each(function (patch) {
-        if (!patch.a ^ !isBackward) {
-          obj[patch.k] = patch.a || patch.d
-        } else {
-          delete obj[patch.k]
-        }
-      })
-    }
-  }
-
-  var markerKeys = []
-  var markerIdxMap = Object.create(null)
-  var result = {
-    text: makePatchableText(content, markerKeys, markerIdxMap),
-    properties: cloneObject(content.properties),
-    discussions: stripDiscussionOffsets(content.discussions),
-    comments: cloneObject(content.comments)
-  }
-
-  contentChanges.cl_each(function (contentChange) {
-    var textPatches = contentChange.text || []
-    if (isBackward) {
-      textPatches = textPatches.slice().reverse()
-    }
-    result.text = textPatches.cl_reduce(function (text, patch) {
-      var isAdd = !patch.a ^ !isBackward
-      var textChanges = patch.a || patch.d || ''
-      // When no marker is present, textChanges is a string
-      if (typeof textChanges === 'string') {
-        textChanges = [textChanges]
-      }
-      var textChange = textChanges.cl_map(function (textChange) {
-        if (!textChange.type) {
-          // textChange is a string
-          return textChange
-        }
-        // textChange is a marker
-        var markerKey = textChange.id + textChange.name
-        var idx = markerIdxMap[markerKey]
-        if (idx === undefined) {
-          idx = markerKeys.length
-          markerIdxMap[markerKey] = idx
-          markerKeys.push({
-            id: textChange.id,
-            offsetName: textChange.name
-          })
-        }
-        return String.fromCharCode(0xe000 + idx)
-      }).join('')
-      if (!textChange) {
-        return text
-      } else if (isAdd) {
-        return text.slice(0, patch.o).concat(textChange).concat(text.slice(patch.o))
-      } else {
-        return text.slice(0, patch.o).concat(text.slice(patch.o + textChange.length))
-      }
-    }, result.text)
-
-    applyObjectPatches(result.properties, contentChange.properties)
-    applyObjectPatches(result.discussions, contentChange.discussions)
-    applyObjectPatches(result.comments, contentChange.comments)
-  })
-
-  restoreDiscussionOffsets(result, markerKeys)
-  return result
-}
-
-function serializeObject (obj) {
-  return JSON.stringify(obj, function (key, value) {
-    return Object.prototype.toString.call(value) === '[object Object]'
-      ? Object.keys(value).sort().cl_reduce(function (sorted, key) {
-        sorted[key] = value[key]
-        return sorted
-      }, {})
-      : value
-  })
-}
-
-function hashArray (arr, valueHash, valueArray) {
-  var hash = []
-  arr.cl_each(function (obj) {
-    var serializedObj = serializeObject(obj)
-    var objHash = valueHash[serializedObj]
-    if (objHash === undefined) {
-      objHash = valueArray.length
-      valueArray.push(obj)
-      valueHash[serializedObj] = objHash
-    }
-    hash.push(objHash)
-  })
-  return String.fromCharCode.apply(null, hash)
-}
-
-function hashObject (obj, valueHash, valueArray) {
-  return hashArray(Object.keys(obj || {}).sort().cl_map(function (key) {
-    return [key, obj[key]]
-  }), valueHash, valueArray)
-}
-
-function mergeText (oldText, newText, serverText) {
-  var diffs = diffMatchPatch.diff_main(oldText, newText)
-  diffMatchPatch.diff_cleanupSemantic(diffs)
-  var patches = diffMatchPatch.patch_make(oldText, diffs)
-  var patchResult = diffMatchPatch.patch_apply(patches, serverText)
-  if (!patchResult[1]
-      .cl_some(function (changeApplied) {
-        return !changeApplied
-      })) {
-    return patchResult[0]
-  }
-
-  diffs = diffMatchPatchStrict.diff_main(patchResult[0], newText)
-  diffMatchPatch.diff_cleanupSemantic(diffs)
-  return diffs.cl_map(function (diff) {
-    return diff[1]
-  }).join('')
-}
-
-function quickPatch (oldStr, newStr, destStr, strict) {
-  var dmp = strict ? diffMatchPatchStrict : diffMatchPatch
-  var diffs = dmp.diff_main(oldStr, newStr)
-  var patches = dmp.patch_make(oldStr, diffs)
-  var patchResult = dmp.patch_apply(patches, destStr)
-  return patchResult[0]
-}
-
-function mergeObjects (oldObject, newObject, serverObject) {
-  var mergedObject = ({}).cl_extend(newObject).cl_extend(serverObject)
-  mergedObject.cl_each(function (value, key) {
-    if (!oldObject[key]) {
-      return // There might be conflict, keep the server value
-    }
-    var newValue = newObject[key] && serializeObject(newObject[key])
-    var serverValue = serverObject[key] && serializeObject(serverObject[key])
-    if (newValue === serverValue) {
-      return // no conflict
-    }
-    var oldValue = serializeObject(oldObject[key])
-    if (oldValue !== newValue && !serverValue) {
-      return // Removed on server but changed on client
-    }
-    if (oldValue !== serverValue && !newValue) {
-      return // Removed on client but changed on server
-    }
-    if (oldValue !== newValue && oldValue === serverValue) {
-      // Take the client value
-      if (!newValue) {
-        delete mergedObject[key]
-      } else {
-        mergedObject[key] = newObject[key]
-      }
-    } else if (oldValue !== serverValue && oldValue === newValue) {
-      // Take the server value
-      if (!serverValue) {
-        delete mergedObject[key]
-      }
-    }
-  // Take the server value otherwise
-  })
-  return cloneObject(mergedObject)
-}
-
-function mergeFlattenContent (oldContent, newContent, serverContent) {
-  var markerKeys = []
-  var markerIdxMap = Object.create(null)
-  var oldText = makePatchableText(oldContent, markerKeys, markerIdxMap)
-  var serverText = makePatchableText(serverContent, markerKeys, markerIdxMap)
-  var localText = makePatchableText(newContent, markerKeys, markerIdxMap)
-  var isServerTextChanges = oldText !== serverText
-  var isTextSynchronized = serverText === localText
-
-  var result = {
-    text: isTextSynchronized || !isServerTextChanges
-      ? localText
-      : mergeText(oldText, serverText, localText),
-    properties: mergeObjects(
-      oldContent.properties,
-      newContent.properties,
-      serverContent.properties
-    ),
-    discussions: mergeObjects(
-      stripDiscussionOffsets(oldContent.discussions),
-      stripDiscussionOffsets(newContent.discussions),
-      stripDiscussionOffsets(serverContent.discussions)
-    ),
-    comments: mergeObjects(
-      oldContent.comments,
-      newContent.comments,
-      serverContent.comments
-    )
-  }
-  restoreDiscussionOffsets(result, markerKeys)
-  return result
-}
-
-export default clDiffUtils;

src/services/diffUtils.js

@@ -0,0 +1,204 @@
+import DiffMatchPatch from 'diff-match-patch';
+import utils from './utils';
+
+const diffMatchPatch = new DiffMatchPatch();
+const diffMatchPatchStrict = new DiffMatchPatch();
+diffMatchPatchStrict.Match_Threshold = 0;
+diffMatchPatchStrict.Patch_DeleteThreshold = 0;
+const diffMatchPatchPermissive = new DiffMatchPatch();
+diffMatchPatchPermissive.Match_Distance = 999999999;
+
+function makePatchableText(content, markerKeys, markerIdxMap) {
+  const markers = [];
+  // Sort keys to have predictable marker positions in case of same offset
+  const discussionKeys = Object.keys(content.discussions).sort();
+  discussionKeys.forEach((discussionId) => {
+    const discussion = content.discussions[discussionId];
+
+    function addMarker(offsetName) {
+      const markerKey = discussionId + offsetName;
+      if (discussion[offsetName] !== undefined) {
+        let idx = markerIdxMap[markerKey];
+        if (idx === undefined) {
+          idx = markerKeys.length;
+          markerIdxMap[markerKey] = idx;
+          markerKeys.push({
+            id: discussionId,
+            offsetName,
+          });
+        }
+        markers.push({
+          idx,
+          offset: discussion[offsetName],
+        });
+      }
+    }
+
+    if (discussion.offset0 === discussion.offset1) {
+      // Remove discussion offsets if markers are at the same position
+      discussion.offset0 = undefined;
+      discussion.offset1 = undefined;
+    } else {
+      addMarker('offset0');
+      addMarker('offset1');
+    }
+  });
+
+  let lastOffset = 0;
+  let result = '';
+  markers
+    .sort((marker1, marker2) => marker1.offset - marker2.offset)
+    .forEach((marker) => {
+      result +=
+        content.text.slice(lastOffset, marker.offset) +
+        String.fromCharCode(0xe000 + marker.idx); // Use a character from the private use area
+      lastOffset = marker.offset;
+    });
+  return result + content.text.slice(lastOffset);
+}
+
+function stripDiscussionOffsets(objectMap) {
+  const result = {};
+  Object.keys(objectMap).forEach((id) => {
+    result[id] = {
+      text: objectMap[id].text,
+    };
+  });
+  return result;
+}
+
+function restoreDiscussionOffsets(content, markerKeys) {
+  const len = content.text.length;
+  const maxIdx = markerKeys.length;
+  for (let i = 0; i < len; i += 1) {
+    const idx = content.text.charCodeAt(i) - 0xe000;
+    if (idx >= 0 && idx < maxIdx) {
+      const markerKey = markerKeys[idx];
+      content.text = content.text.slice(0, i) + content.text.slice(i + 1);
+      const discussion = content.discussions[markerKey.id];
+      if (discussion) {
+        discussion[markerKey.offsetName] = i;
+      }
+      // We just removed the current character, we may have multiple markers with same offset
+      i -= 1;
+    }
+  }
+}
+
+function serializeObject(obj) {
+  if (!obj) {
+    return obj;
+  }
+  return JSON.stringify(obj, (key, value) => {
+    if (Object.prototype.toString.call(value) !== '[object Object]') {
+      return value;
+    }
+    return Object.keys(value).sort().reduce((sorted, valueKey) => {
+      sorted[valueKey] = value[valueKey];
+      return sorted;
+    }, {});
+  });
+}
+
+function mergeText(oldText, newText, serverText) {
+  let diffs = diffMatchPatch.diff_main(oldText, newText);
+  diffMatchPatch.diff_cleanupSemantic(diffs);
+  const patches = diffMatchPatch.patch_make(oldText, diffs);
+  const patchResult = diffMatchPatch.patch_apply(patches, serverText);
+  if (!patchResult[1].some(changeApplied => !changeApplied)) {
+    return patchResult[0];
+  }
+
+  diffs = diffMatchPatchStrict.diff_main(patchResult[0], newText);
+  diffMatchPatch.diff_cleanupSemantic(diffs);
+  return diffs.map(diff => diff[1]).join('');
+}
+
+function quickPatch(oldStr, newStr, destStr, strict) {
+  const dmp = strict ? diffMatchPatchStrict : diffMatchPatch;
+  const diffs = dmp.diff_main(oldStr, newStr);
+  const patches = dmp.patch_make(oldStr, diffs);
+  const patchResult = dmp.patch_apply(patches, destStr);
+  return patchResult[0];
+}
+
+function mergeValue(oldValue, newValue, serverValue) {
+  if (!oldValue) {
+    return serverValue; // There might be conflict, keep the server value
+  }
+  const newSerializedValue = serializeObject(newValue);
+  const serverSerializedValue = serializeObject(serverValue);
+  if (newSerializedValue === serverSerializedValue) {
+    return serverValue; // no conflict
+  }
+  const oldSerializedValue = serializeObject(oldValue);
+  if (oldSerializedValue !== newSerializedValue && !serverValue) {
+    return newValue; // Removed on server but changed on client
+  }
+  if (oldSerializedValue !== serverSerializedValue && !newValue) {
+    return serverValue; // Removed on client but changed on server
+  }
+  if (oldSerializedValue !== newSerializedValue && oldSerializedValue === serverSerializedValue) {
+    return newValue; // Take the client value
+  }
+  return serverValue; // Take the server value otherwise
+}
+
+function mergeObjects(oldObject, newObject, serverObject) {
+  const mergedObject = {};
+  Object.keys({
+    ...newObject,
+    ...serverObject,
+  }).forEach((key) => {
+    const mergedValue = mergeValue(oldObject[key], newObject[key], serverObject[key]);
+    if (mergedValue != null) {
+      mergedObject[key] = mergedValue;
+    }
+  });
+  return utils.deepCopy(mergedObject);
+}
+
+function mergeContent(oldContent, newContent, serverContent) {
+  const markerKeys = [];
+  const markerIdxMap = Object.create(null);
+  const oldText = makePatchableText(oldContent, markerKeys, markerIdxMap);
+  const serverText = makePatchableText(serverContent, markerKeys, markerIdxMap);
+  const localText = makePatchableText(newContent, markerKeys, markerIdxMap);
+  const isServerTextChanges = oldText !== serverText;
+  const isTextSynchronized = serverText === localText;
+
+  const result = {
+    text: isTextSynchronized || !isServerTextChanges
+      ? localText
+      : mergeText(oldText, serverText, localText),
+    properties: mergeValue(
+      oldContent.properties,
+      newContent.properties,
+      serverContent.properties,
+    ),
+    discussions: mergeObjects(
+      stripDiscussionOffsets(oldContent.discussions),
+      stripDiscussionOffsets(newContent.discussions),
+      stripDiscussionOffsets(serverContent.discussions),
+    ),
+    comments: mergeObjects(
+      oldContent.comments,
+      newContent.comments,
+      serverContent.comments,
+    ),
+  };
+  restoreDiscussionOffsets(result, markerKeys);
+  return result
+}
+
+export default {
+  serializeObject,
+  makePatchableText,
+  restoreDiscussionOffsets,
+  applyContentChanges,
+  getTextPatches,
+  getObjectPatches,
+  quickPatch,
+  mergeObjects,
+  mergeContent,
+};

src/services/helpers/googleHelper.js

@@ -23,11 +23,11 @@ const tokenExpirationMargin = 10 * 60 * 1000; // 10 min
 //   ],
 // };
 
-const request = (googleToken, options) => utils.request({
+const request = (token, options) => utils.request({
   ...options,
   headers: {
     ...options.headers,
-    Authorization: `Bearer ${googleToken.accessToken}`,
+    Authorization: `Bearer ${token.accessToken}`,
   },
 });
 
@@ -68,28 +68,28 @@ export default {
         };
       }))
       // Call the tokeninfo endpoint
-      .then(googleToken => request(googleToken, {
+      .then(token => request(token, {
         method: 'GET',
         url: 'https://www.googleapis.com/plus/v1/people/me',
       }).then((res) => {
-        // Add name to googleToken
+        // Add name to token
-        googleToken.name = res.body.displayName;
+        token.name = res.body.displayName;
-        const existingToken = store.getters['data/googleTokens'][googleToken.sub];
+        const existingToken = store.getters['data/googleTokens'][token.sub];
         if (existingToken) {
           if (!sub) {
             throw new Error('Google account already linked.');
           }
-          // Add isLogin and nextPageToken to googleToken
+          // Add isLogin and nextPageToken to token
-          googleToken.isLogin = existingToken.isLogin;
+          token.isLogin = existingToken.isLogin;
-          googleToken.nextPageToken = existingToken.nextPageToken;
+          token.nextPageToken = existingToken.nextPageToken;
         }
-        // Add googleToken to googleTokens
+        // Add token to googleTokens
-        store.dispatch('data/setGoogleToken', googleToken);
+        store.dispatch('data/setGoogleToken', token);
-        return googleToken;
+        return token;
       }));
   },
-  refreshToken(scopes, googleToken) {
+  refreshToken(scopes, token) {
-    const sub = googleToken.sub;
+    const sub = token.sub;
     const lastToken = store.getters['data/googleTokens'][sub];
     const mergedScopes = [...new Set([
       ...scopes,
@@ -115,9 +115,9 @@ export default {
           .catch(() => this.startOauth2(mergedScopes, sub));
       });
   },
-  getChanges(googleToken) {
+  getChanges(token) {
     let changes = [];
-    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], googleToken)
+    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], token)
       .then((refreshedToken) => {
         const getPage = (pageToken = '1') => request(refreshedToken, {
           method: 'GET',
@@ -158,8 +158,8 @@ export default {
         return getPage(refreshedToken.nextPageToken);
       });
   },
-  updateNextPageToken(googleToken, changes) {
+  updateNextPageToken(token, changes) {
-    const lastToken = store.getters['data/googleTokens'][googleToken.sub];
+    const lastToken = store.getters['data/googleTokens'][token.sub];
     if (changes.nextPageToken !== lastToken.nextPageToken) {
       store.dispatch('data/setGoogleToken', {
         ...lastToken,
@@ -167,8 +167,8 @@ export default {
       });
     }
   },
-  saveItem(googleToken, item, syncData, ifNotTooLate = cb => res => cb(res)) {
+  saveItem(token, item, syncData, ifNotTooLate = cb => res => cb(res)) {
-    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], googleToken)
+    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], token)
       // Refreshing a token can take a while if an oauth window pops up, so check if it's too late
       .then(ifNotTooLate((refreshedToken) => {
         const options = {
@@ -229,12 +229,22 @@ export default {
         }));
       }));
   },
-  removeItem(googleToken, syncData, ifNotTooLate = cb => res => cb(res)) {
+  removeItem(token, syncData, ifNotTooLate = cb => res => cb(res)) {
-    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], googleToken)
+    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], token)
       // Refreshing a token can take a while if an oauth window pops up, so check if it's too late
       .then(ifNotTooLate(refreshedToken => request(refreshedToken, {
         method: 'DELETE',
         url: `https://www.googleapis.com/drive/v3/files/${syncData.id}`,
       })).then(() => syncData));
   },
+  downloadFile(refreshedToken, id) {
+    return request(refreshedToken, {
+      method: 'GET',
+      url: `https://www.googleapis.com/drive/v3/files/${id}?alt=media`,
+    }).then(res => res.body);
+  },
+  downloadAppDataFile(token, id) {
+    return this.refreshToken(['https://www.googleapis.com/auth/drive.appdata'], token)
+      .then(refreshedToken => this.downloadFile(refreshedToken, id));
+  },
 };

src/services/localDbSvc.js

@@ -86,16 +86,11 @@ utils.types.forEach((type) => {
   updatedMap[type] = Object.create(null);
 });
 
-function isContentType(type) {
+const contentTypes = {
-  switch (type) {
+  content: true,
-    case 'content':
+  contentState: true,
-    case 'contentState':
+  syncContent: true,
-    case 'syncContent':
+};
-      return true;
-    default:
-      return false;
-  }
-}
 
 export default {
   lastTx: 0,
@@ -171,8 +166,8 @@ export default {
     Object.keys(this.updatedMap).forEach((type) => {
       // Remove this type only if file is deleted
       let checker = cb => id => !storeItemMap[id] && cb(id);
-      if (isContentType(type)) {
+      if (contentTypes[type]) {
-        // For content types, remove only if file is deleted
+        // For content types, remove item only if file is deleted
         checker = cb => (id) => {
           if (!storeItemMap[id]) {
             const [fileId] = id.split('/');
@@ -227,7 +222,7 @@ export default {
       // DB item is different from the corresponding store item
       this.updatedMap[dbItem.type][dbItem.id] = dbItem.updated;
       // Update content only if it exists in the store
-      if (existingStoreItem || !isContentType(dbItem.type)) {
+      if (existingStoreItem || !contentTypes[dbItem.type]) {
         // Put item in the store
         store.commit(`${dbItem.type}/setItem`, dbItem);
         storeItemMap[dbItem.id] = dbItem;
@@ -236,9 +231,9 @@ export default {
   },
 
   /**
-   * Retrieve an item from the DB.
+   * Retrieve an item from the DB and put it in the store.
    */
-  retrieveItem(id) {
+  loadItem(id) {
     // Check if item is in the store
     const itemInStore = store.getters.allItemMap[id];
     if (itemInStore) {
@@ -259,11 +254,30 @@ export default {
             this.updatedMap[dbItem.type][dbItem.id] = dbItem.updated;
             // Put item in the store
             store.commit(`${dbItem.type}/setItem`, dbItem);
-            // Use deepCopy to freeze item
             resolve(dbItem);
           }
         };
       }, () => onError());
     });
   },
+
+  /**
+   * Unload from the store contents that haven't been opened recently
+   */
+  unloadContents() {
+    const lastOpenedFileIds = store.getters['data/lastOpenedIds']
+      .slice(0, 10).reduce((result, id) => {
+        result[id] = true;
+        return result;
+      }, {});
+    Object.keys(contentTypes).forEach((type) => {
+      store.getters(`${type}/items`).forEach((item) => {
+        const [fileId] = item.id.split('/');
+        if (!lastOpenedFileIds[fileId]) {
+          // Remove item from the store
+          store.commit(`${type}/deleteItem`, item.id);
+        }
+      });
+    });
+  },
 };

src/services/providers/gdriveAppDataProvider.js

@@ -1 +1,24 @@
-export default {};
+import store from '../../store';
+import googleHelper from '../helpers/googleHelper';
+
+export default {
+  downloadContent(token, fileId) {
+    const syncData = store.getters['data/syncDataByItemId'][`${fileId}/content`];
+    return googleHelper.downloadAppDataFile(token, syncData.id)
+      .then((content) => {
+        if (content.updated !== syncData.updated) {
+          store.dispatch('data/setSyncData', {
+            ...store.getters['data/syncData'],
+            [syncData.id]: {
+              ...syncData,
+              updated: content.updated,
+            },
+          });
+        }
+        return {
+          history: [],
+          ...content,
+        };
+      });
+  },
+};

src/services/syncSvc.js

@@ -5,8 +5,6 @@ import utils from './utils';
 import userActivitySvc from './userActivitySvc';
 import gdriveAppDataProvider from './providers/gdriveAppDataProvider';
 import googleHelper from './helpers/googleHelper';
-import emptyContent from '../data/emptyContent';
-import emptySyncContent from '../data/emptySyncContent';
 
 const lastSyncActivityKey = 'lastSyncActivity';
 let lastSyncActivity;
@@ -36,6 +34,7 @@ function setLastSyncActivity() {
 
 function getSyncProvider(syncLocation) {
   switch (syncLocation.provider) {
+    case 'gdriveAppData':
     default:
       return gdriveAppDataProvider;
   }
@@ -43,11 +42,21 @@ function getSyncProvider(syncLocation) {
 
 function getSyncToken(syncLocation) {
   switch (syncLocation.provider) {
+    case 'gdriveAppData':
     default:
       return store.getters['data/loginToken'];
   }
 }
 
+const loader = type => fileId => localDbSvc.loadItem(`${fileId}/${type}`)
+  // Item does not exist, create it
+  .catch(() => store.commit(`${type}/setItem`, {
+    id: `${fileId}/${type}`,
+  }));
+const loadContent = loader('content');
+const loadSyncContent = loader('syncContent');
+const loadContentState = loader('contentState');
+
 function applyChanges(changes) {
   const storeItemMap = { ...store.getters.allItemMap };
   const syncData = { ...store.getters['data/syncData'] };
@@ -164,23 +173,51 @@ function sync() {
         const existingSyncData = store.getters['data/syncDataByItemId'][contentId];
       });
 
-      const syncOneContent = fileId => localDbSvc.retrieveItem(`${fileId}/syncContent`)
+      const syncOneContent = fileId => loadSyncContent(fileId)
-        .catch(() => ({ ...emptySyncContent(), id: `${fileId}/syncContent` }))
+        .then(() => loadContent(fileId))
-        .then(syncContent => localDbSvc.retrieveItem(`${fileId}/content`)
-          .catch(() => ({ ...emptyContent(), id: `${fileId}/content` }))
-          .then((content) => {
-            const syncOneContentLocation = (syncLocation) => {
-              return Promise.resolve()
         .then(() => {
+          const getContent = () => store.state.content.itemMap[`${fileId}/content`];
+          const getSyncContent = () => store.state.content.itemMap[`${fileId}/syncContent`];
+
+          const syncLocations = [
+            { id: 'main', provider: 'gdriveAppData' },
+            ...getContent().syncLocations.filter(syncLocation => getSyncToken(syncLocation),
+          )];
+          const downloadedLocations = {};
+
+          const syncOneContentLocation = () => {
+            let result;
+            syncLocations.some((syncLocation) => {
+              if (!downloadedLocations[syncLocation.id]) {
                 const provider = getSyncProvider(syncLocation);
                 const token = getSyncToken(syncLocation);
-                  return provider && token && provider.downloadContent()
+                result = provider && token && provider.downloadContent(fileId, syncLocation)
+                  .then((content) => {
+                    const syncContent = getSyncContent();
+                    const syncLocationData = syncContent.syncLocationData[syncLocation.id] || {
+                      history: [],
+                    };
+                    let lastMergedContent;
+                    syncLocationData.history.some((updated) => {
+                      if (content.history.indexOf(updated) !== -1) {
+
+                      }
+                      return lastMergedContent;
                     });
+                  })
+                  .then(() => syncOneContentLocation());
+              }
+              return result;
+            });
+            return result;
           };
 
-            const syncLocations = [{ provider: null }, ...content.syncLocations];
+          return syncOneContentLocation();
-            return syncOneContentLocation(syncLocations[0]);
+        })
-          }));
+        .then(() => localDbSvc.unloadContents(), (err) => {
+          localDbSvc.unloadContents();
+          throw err;
+        });
 
       // Called until no content to save
       const saveNextContent = ifNotTooLate(() => {
@@ -189,7 +226,7 @@ function sync() {
           const updated = getContentUpdated(contentId);
           const existingSyncData = store.getters['data/syncDataByItemId'][contentId];
           if (!existingSyncData || existingSyncData.updated !== updated) {
-            saveContentPromise = localDbSvc.retrieveItem(contentId)
+            saveContentPromise = localDbSvc.loadItem(contentId)
               .then(content => googleHelper.saveItem(
                 googleToken,
                 // Use deepCopy to freeze objects
@@ -299,19 +336,11 @@ localDbSvc.sync()
         store.dispatch('data/setLastOpenedId', currentFile.id);
         return Promise.resolve()
           // Load contentState from DB
-          .then(() => localDbSvc.retrieveItem(`${currentFile.id}/contentState`)
+          .then(() => loadContentState(currentFile.id))
-            // contentState does not exist, create it
-            .catch(() => store.commit('contentState/setItem', {
-              id: `${currentFile.id}/contentState`,
-            })))
           // Load syncContent from DB
-          .then(() => localDbSvc.retrieveItem(`${currentFile.id}/syncContent`)
+          .then(() => loadSyncContent(currentFile.id))
-            // syncContent does not exist, create it
-            .catch(() => store.commit('syncContent/setItem', {
-              id: `${currentFile.id}/syncContent`,
-            })))
           // Load content from DB
-          .then(() => localDbSvc.retrieveItem(`${currentFile.id}/content`));
+          .then(() => localDbSvc.loadItem(`${currentFile.id}/content`));
       }),
     {
       immediate: true,
@@ -320,6 +349,14 @@ localDbSvc.sync()
 // Sync local DB periodically
 utils.setInterval(() => localDbSvc.sync(), 1000);
 
+// Unload contents from memory periodically
+utils.setInterval(() => {
+  // Wait for sync and publish to finish
+  if (store.state.queue.isEmpty) {
+    localDbSvc.unloadContents();
+  }
+}, 5000);
+
 export default {
   isSyncAvailable,
   requestSync,

src/store/modules/data.js

@@ -25,13 +25,13 @@ const patcher = id => ({ state, commit }, data) => {
     },
   });
 };
-const localSettingsToggler = propertyName => ({ getters, dispatch }, value) => dispatch('patchLocalSettings', {
-  [propertyName]: value === undefined ? !getters.localSettings[propertyName] : value,
-});
 
 // Local settings
 module.getters.localSettings = getter('localSettings');
 module.actions.patchLocalSettings = patcher('localSettings');
+const localSettingsToggler = propertyName => ({ getters, dispatch }, value) => dispatch('patchLocalSettings', {
+  [propertyName]: value === undefined ? !getters.localSettings[propertyName] : value,
+});
 module.actions.toggleNavigationBar = localSettingsToggler('showNavigationBar');
 module.actions.toggleEditor = localSettingsToggler('showEditor');
 module.actions.toggleSidePreview = localSettingsToggler('showSidePreview');
@@ -48,7 +48,7 @@ module.getters.lastOpened = getter('lastOpened');
 const getLastOpenedIds = (lastOpened, rootState) => Object.keys(lastOpened)
   .filter(id => rootState.file.itemMap[id])
   .sort((id1, id2) => lastOpened[id2] - lastOpened[id1])
-  .slice(0, 10);
+  .slice(0, 20);
 module.getters.lastOpenedIds = (state, getters, rootState) =>
   getLastOpenedIds(getters.lastOpened, rootState);
 module.actions.setLastOpenedId = ({ getters, commit, rootState }, fileId) => {
@@ -80,18 +80,18 @@ module.actions.setSyncData = setter('syncData');
 module.getters.tokens = getter('tokens');
 module.getters.googleTokens = (state, getters) => getters.tokens.google || {};
 module.getters.loginToken = (state, getters) => {
-  // Return the first googleToken that has the isLogin flag
+  // Return the first google token that has the isLogin flag
   const googleTokens = getters.googleTokens;
   const loginSubs = Object.keys(googleTokens)
     .filter(sub => googleTokens[sub].isLogin);
   return googleTokens[loginSubs[0]];
 };
 module.actions.patchTokens = patcher('tokens');
-module.actions.setGoogleToken = ({ getters, dispatch }, googleToken) => {
+module.actions.setGoogleToken = ({ getters, dispatch }, token) => {
   dispatch('patchTokens', {
     google: {
       ...getters.googleTokens,
-      [googleToken.sub]: googleToken,
+      [token.sub]: token,
     },
   });
 };