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159 lines (140 loc) · 5.42 KB
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var SourceDiff = SourceDiff || {};
SourceDiff.LineDiff = function() {
var _added = [];
var _deleted = [];
var _common = [];
var addCommon = function(leftPosition, rightPosition) {
_common.unshift({
leftPosition: leftPosition,
leftEndPosition: leftPosition,
rightPosition: rightPosition,
rightEndPosition: rightPosition
});
};
var addDelete = function(position) {
_deleted.unshift({
position: position,
endPosition: position});
};
var addInsert = function(position) {
_added.unshift({
position: position,
endPosition: position});
};
var editLength = function(edit) {
if (!edit) {
return 0;
}
return edit.endPosition - edit.position + 1;
};
var cleanUp = function() {
mergeAdjacent(_added);
mergeAdjacent(_deleted);
mergeAdjacentCommon();
do {
var didMerge = false;
for (var i = 0; i < _common.length; i++) {
var equalityLength = _common[i].leftEndPosition - _common[i].leftPosition + 1;
var leftDelete = findEditWithEndingPosition(_deleted, _common[i].leftPosition - 1);
var rightDelete = findEditWithPosition(_deleted, _common[i].leftEndPosition + 1);
var leftAdd = findEditWithEndingPosition(_added, _common[i].rightPosition - 1);
var rightAdd = findEditWithPosition(_added, _common[i].rightEndPosition + 1);
if (equalityLength <= 8 && editLength(leftDelete) + editLength(leftAdd) >= equalityLength
&& editLength(rightDelete) + editLength(rightAdd) >= equalityLength) {
didMerge = true;
if (leftDelete && rightDelete) {
leftDelete.endPosition = rightDelete.endPosition;
removeEdit(_deleted, rightDelete);
} else if(leftDelete) {
leftDelete.endPosition = _common[i].leftEndPosition;
} else if (rightDelete) {
rightDelete.position = _common[i].leftPosition;
} else {
addEdit(_deleted, _common[i].leftPosition, _common[i].leftEndPosition);
}
if (leftAdd && rightAdd) {
leftAdd.endPosition = rightAdd.endPosition;
removeEdit(_added, rightAdd);
} else if (leftAdd) {
leftAdd.endPosition = _common[i].rightEndPosition;
} else if (rightAdd) {
rightAdd.position = _common[i].rightPosition;
} else {
addEdit(_added, _common[i].rightPosition, _common[i].rightEndPosition);
}
_common.splice(i, 1);
}
}
} while (didMerge)
};
var mergeAdjacentCommon = function () {
for (var i = 0; i < _common.length; i++) {
if (i + 1 < _common.length
&& _common[i].leftEndPosition + 1 === _common[i + 1].leftPosition
&& _common[i].rightEndPosition + 1 === _common[i + 1].rightPosition) {
_common[i].leftEndPosition = _common[i + 1].leftEndPosition;
_common[i].rightEndPosition = _common[i + 1].rightEndPosition;
_common.splice(i + 1, 1);
i--;
}
}
};
var addEdit = function(edits, position, endPosition) {
var newEdit = {
position: position,
endPosition: endPosition
};
if (edits.length === 0) {
edits.push(newEdit);
} else if (position < edits[0].position) {
edits.unshift(newEdit);
} else {
for (var i = edits.length - 1; i >= 0; i--) {
if (position > edits[i].position) {
edits.splice(i + 1, 0, newEdit);
break;
}
}
}
};
var removeEdit = function(edits, item) {
for (var i = 0; i < edits.length; i++) {
if (edits[i] === item) {
edits.splice(i, 1);
break;
}
}
};
var findEditWithPosition = function(edits, pos) {
for (var i = 0; i < edits.length; i++) {
if (edits[i].position === pos) {
return edits[i];
}
}
};
var findEditWithEndingPosition = function(edits, endPos) {
for (var i = 0; i < edits.length; i++) {
if (edits[i].endPosition === endPos) {
return edits[i];
}
}
};
var mergeAdjacent = function (edits) {
for (var i = 0; i < edits.length; i++) {
if (i + 1 < edits.length && edits[i].endPosition + 1 === edits[i + 1].position) {
edits[i].endPosition = edits[i + 1].endPosition;
edits.splice(i + 1, 1);
i--;
}
}
};
return {
addDelete: addDelete,
addInsert: addInsert,
addCommon: addCommon,
cleanUp: cleanUp,
added: _added,
deleted: _deleted,
common: _common
};
};