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add better helpers for finding and resetting the cursor

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pull/1/head
ansuz 9 years ago
parent 7e7f1fee76
commit de46be85ba
1 changed files with 184 additions and 26 deletions
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208
www/common/cursor.js
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@ -127,11 +127,89 @@ define([
};
}
} else {
error("[seekToDelta] el is undefined");
error("[cursor.seekToDelta] el is undefined");
}
return result;
};
var checkFromEnd = cursor.checkFromEnd = function (root, predicate) {
var last = Tree.rightmostNode(root);
var success = false;
var i = 0;
while (last && !success) {
success = predicate(last, i++);
last = Tree.previousNode(last, root);
}
return success;
};
/* uses closure to capture the root node because I'm lazy
*/
var getTrailingNodes = cursor.getTrailingNodes = function (el) {
var trailing = [];
var success = cursor.checkFromEnd(inner, function (cur) {
if (cur === el) {
trailing.push(cur);
return true;
} else { trailing.push(cur); }
});
return success && trailing;
};
var recoverNodeByTrailing = cursor.recoverNodeByTrailing = function (trailing) {
// clone the array
var T = trailing.slice(0);
var L = T.length;
var el = null;
cursor.checkFromEnd(inner, function (cur, i) {
if (i >= L) {
//console.log("[cursor.recoverNodeByTrailing] out of bounds");
return true;
} else {
if (cur.nodeName !== T[i].nodeName) {
console.log("[cursor.recoverNodeByTrailing] false name");
console.log(cur);
return true;
} else if (cur.nodeName === T[i].nodeName && i === L - 1) {
el = cur;
return true;
} else {
return false;
}
}
});
return el;
};
/* cursor.find uses information produced by side effects of 'update'
to recover the cursor
*/
cursor.find = function () {
['start', 'end'].forEach(function (pos) {
// is this metric even reliable?
var node;
var trailing = Range[pos].trailing;
if (Range[pos].lost) {
if (trailing.length) {
// use the trailing nodes to find the node..
node = recoverNodeByTrailing(trailing);
}
if (node) {
// if that worked....great!
Range[pos].el = node;
} else {
// if not, try falling back to the nearest parent?
}
} else {
// it wasn't lost, you don't need to do anything.
}
});
};
/* cursor.update takes notes about wherever the cursor was last seen
in the event of a cursor loss, the information produced by side
effects of this function should be used to recover the cursor
@ -142,31 +220,97 @@ define([
verbose("cursor.update");
root = root || inner;
sel = sel || Rangy.getSelection(root);
//if (!sel.rangeCount) { return 'no ranges found'; }
// FIXME under what circumstances are no ranges found?
if (!sel.rangeCount) {
error('[cursor.update] no ranges found');
//return 'no ranges found';
}
var range = sel.getRangeAt(0);
// Big R Range is caught in closure, and maintains persistent state
Range.start.el = range.startContainer;
Range.start.offset = range.startOffset;
Range.start.parents = Tree.parentsOf(Range.start.el, root);
Range.end.el = range.endContainer;
Range.end.offset = range.endOffset;
Range.end.parents = Tree.parentsOf(Range.end.el, root);
['start', 'end'].forEach(function (pos) {
Range[pos].el = range[pos+'Container'];
Range[pos].offset = range[pos+'Offset'];
Range[pos].parents = Tree.parentsOf(Range[pos].el, root);
// trailing is either an array or false
var trailing = getTrailingNodes(Range[pos].el);
// if it's false, then the cursor has been lost
// TODO do a more careful check to see if the cursor has been destroyed.
Range[pos].lost = !trailing;
if (Range[pos].lost) {
// don't overwrite the previous trailing nodes
// that array will be used to recover the cursor
} else {
// if you haven't lost the cursor, update the node list
Range[pos].trailing = trailing;
}
});
};
/* cursor.find uses information produced by side effects of 'update'
to recover the cursor
*/
cursor.find = function () { };
/* 0 -> neither is lost
1 -> start is lost
2 -> end is lost
3 -> both are lost */
var isLost = cursor.isLost = function () {
var state = ['start', 'end'].map(function (pos, i) {
return Tree.contains(Range[pos].el, inner)? 0 : i + 1;
});
return state[0] | state[1];
};
/*
var recover = cursor.recover = function (lost) {
var sel = Rangy.getSelection(inner);
*/
cursor.recover = function () { };
// create a range to modify
var range = Rangy.createRange();
cursor.delta = function (delta, collapse) {
/* if range is backwards, cursor.delta fails
so check if they're in the expected order
before setting the new range */
if (lost & 1) {
Range.start.el = recoverNodeByTrailing(Range.start.trailing);
}
if (lost & 2) {
Range.end.el = recoverNodeByTrailing(Range.end.trailing);
}
// el.parentNode is null
var order = Tree.orderOfNodes(Range.start.el, Range.end.el, inner);
var backward;
// this could all be one line but nobody would be able to read it
if (order === -1) {
// definitely backward
backward = true;
} else if (order === 0) {
// might be backward, check offsets to know for sure
backward = (Range.start.offset > Range.end.offset);
} else {
// definitely not backward
backward = false;
}
if (backward) {
range.setStart(Range.end.el, Range.end.offset);
range.setEnd(Range.start.el, Range.start.offset);
} else {
range.setStart(Range.start.el, Range.start.offset);
range.setEnd(Range.end.el, Range.end.offset);
}
// actually set the cursor to the new range
sel.setSingleRange(range);
};
cursor.delta = function (delta1, delta2) {
var sel = Rangy.getSelection(inner);
delta2 = (typeof delta2 !== 'undefined') ? delta2 : delta1;
// update returns errors if there are problems
// and updates the persistent Range object
@ -184,13 +328,29 @@ define([
// using infromation about wherever you were last...
// move both parts by some delta
var start = seekToDelta(Range.start.el, delta, Range.start.offset);
var end = seekToDelta(Range.end.el, delta, Range.end.offset);
var start = seekToDelta(Range.start.el, delta1, Range.start.offset);
var end = seekToDelta(Range.end.el, delta2, Range.end.offset);
/* if range is backwards, cursor.delta fails
so check if they're in the expected order
before setting the new range */
if (Tree.orderOfNodes(start.el, end.el, inner) === -1) {
var order = Tree.orderOfNodes(start.el, end.el, inner);
var backward;
// this could all be one line but nobody would be able to read it
if (order === -1) {
// definitely backward
backward = true;
} else if (order === 0) {
// might be backward, check offsets to know for sure
backward = (start.offset > end.offset);
} else {
// definitely not backward
backward = false;
}
if (backward) {
range.setStart(end.el, end.offset);
range.setEnd(start.el, start.offset);
} else {
@ -200,12 +360,10 @@ define([
// actually set the cursor to the new range
sel.setSingleRange(range);
if (delta < 0) {
// seeking left, so start might have an error
return start.error;
} else {
return end.error;
}
return {
startError: start.error,
endError: end.error
};
};
return cursor;

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