The Big Renaming - etherpad is now an NPM module

1 files changed, 213 insertions, 0 deletions

diff --git a/src/static/js/changesettracker.js b/src/static/js/changesettracker.js
new file mode 100644
index 00000000..e34dc107
--- /dev/null
+++ b/src/static/js/changesettracker.js
@@ -0,0 +1,213 @@
+/**
+ * This code is mostly from the old Etherpad. Please help us to comment this code. 
+ * This helps other people to understand this code better and helps them to improve it.
+ * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
+ */
+
+/**
+ * Copyright 2009 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var AttribPool = require('/AttributePoolFactory').createAttributePool;
+var Changeset = require('/Changeset');
+
+function makeChangesetTracker(scheduler, apool, aceCallbacksProvider)
+{
+
+  // latest official text from server
+  var baseAText = Changeset.makeAText("\n");
+  // changes applied to baseText that have been submitted
+  var submittedChangeset = null;
+  // changes applied to submittedChangeset since it was prepared
+  var userChangeset = Changeset.identity(1);
+  // is the changesetTracker enabled
+  var tracking = false;
+  // stack state flag so that when we change the rep we don't
+  // handle the notification recursively.  When setting, always
+  // unset in a "finally" block.  When set to true, the setter
+  // takes change of userChangeset.
+  var applyingNonUserChanges = false;
+
+  var changeCallback = null;
+
+  var changeCallbackTimeout = null;
+
+  function setChangeCallbackTimeout()
+  {
+    // can call this multiple times per call-stack, because
+    // we only schedule a call to changeCallback if it exists
+    // and if there isn't a timeout already scheduled.
+    if (changeCallback && changeCallbackTimeout === null)
+    {
+      changeCallbackTimeout = scheduler.setTimeout(function()
+      {
+        try
+        {
+          changeCallback();
+        }
+        finally
+        {
+          changeCallbackTimeout = null;
+        }
+      }, 0);
+    }
+  }
+
+  var self;
+  return self = {
+    isTracking: function()
+    {
+      return tracking;
+    },
+    setBaseText: function(text)
+    {
+      self.setBaseAttributedText(Changeset.makeAText(text), null);
+    },
+    setBaseAttributedText: function(atext, apoolJsonObj)
+    {
+      aceCallbacksProvider.withCallbacks("setBaseText", function(callbacks)
+      {
+        tracking = true;
+        baseAText = Changeset.cloneAText(atext);
+        if (apoolJsonObj)
+        {
+          var wireApool = (new AttribPool()).fromJsonable(apoolJsonObj);
+          baseAText.attribs = Changeset.moveOpsToNewPool(baseAText.attribs, wireApool, apool);
+        }
+        submittedChangeset = null;
+        userChangeset = Changeset.identity(atext.text.length);
+        applyingNonUserChanges = true;
+        try
+        {
+          callbacks.setDocumentAttributedText(atext);
+        }
+        finally
+        {
+          applyingNonUserChanges = false;
+        }
+      });
+    },
+    composeUserChangeset: function(c)
+    {
+      if (!tracking) return;
+      if (applyingNonUserChanges) return;
+      if (Changeset.isIdentity(c)) return;
+      userChangeset = Changeset.compose(userChangeset, c, apool);
+
+      setChangeCallbackTimeout();
+    },
+    applyChangesToBase: function(c, optAuthor, apoolJsonObj)
+    {
+      if (!tracking) return;
+
+      aceCallbacksProvider.withCallbacks("applyChangesToBase", function(callbacks)
+      {
+
+        if (apoolJsonObj)
+        {
+          var wireApool = (new AttribPool()).fromJsonable(apoolJsonObj);
+          c = Changeset.moveOpsToNewPool(c, wireApool, apool);
+        }
+
+        baseAText = Changeset.applyToAText(c, baseAText, apool);
+
+        var c2 = c;
+        if (submittedChangeset)
+        {
+          var oldSubmittedChangeset = submittedChangeset;
+          submittedChangeset = Changeset.follow(c, oldSubmittedChangeset, false, apool);
+          c2 = Changeset.follow(oldSubmittedChangeset, c, true, apool);
+        }
+
+        var preferInsertingAfterUserChanges = true;
+        var oldUserChangeset = userChangeset;
+        userChangeset = Changeset.follow(c2, oldUserChangeset, preferInsertingAfterUserChanges, apool);
+        var postChange = Changeset.follow(oldUserChangeset, c2, !preferInsertingAfterUserChanges, apool);
+
+        var preferInsertionAfterCaret = true; //(optAuthor && optAuthor > thisAuthor);
+        applyingNonUserChanges = true;
+        try
+        {
+          callbacks.applyChangesetToDocument(postChange, preferInsertionAfterCaret);
+        }
+        finally
+        {
+          applyingNonUserChanges = false;
+        }
+      });
+    },
+    prepareUserChangeset: function()
+    {
+      // If there are user changes to submit, 'changeset' will be the
+      // changeset, else it will be null.
+      var toSubmit;
+      if (submittedChangeset)
+      {
+        // submission must have been canceled, prepare new changeset
+        // that includes old submittedChangeset
+        toSubmit = Changeset.compose(submittedChangeset, userChangeset, apool);
+      }
+      else
+      {
+        if (Changeset.isIdentity(userChangeset)) toSubmit = null;
+        else toSubmit = userChangeset;
+      }
+
+      var cs = null;
+      if (toSubmit)
+      {
+        submittedChangeset = toSubmit;
+        userChangeset = Changeset.identity(Changeset.newLen(toSubmit));
+
+        cs = toSubmit;
+      }
+      var wireApool = null;
+      if (cs)
+      {
+        var forWire = Changeset.prepareForWire(cs, apool);
+        wireApool = forWire.pool.toJsonable();
+        cs = forWire.translated;
+      }
+
+      var data = {
+        changeset: cs,
+        apool: wireApool
+      };
+      return data;
+    },
+    applyPreparedChangesetToBase: function()
+    {
+      if (!submittedChangeset)
+      {
+        // violation of protocol; use prepareUserChangeset first
+        throw new Error("applySubmittedChangesToBase: no submitted changes to apply");
+      }
+      //bumpDebug("applying committed changeset: "+submittedChangeset.encodeToString(false));
+      baseAText = Changeset.applyToAText(submittedChangeset, baseAText, apool);
+      submittedChangeset = null;
+    },
+    setUserChangeNotificationCallback: function(callback)
+    {
+      changeCallback = callback;
+    },
+    hasUncommittedChanges: function()
+    {
+      return !!(submittedChangeset || (!Changeset.isIdentity(userChangeset)));
+    }
+  };
+
+}
+
+exports.makeChangesetTracker = makeChangesetTracker;