var Ap = Array.prototype;
var slice = Ap.slice;
var map = Ap.map;
var Op = Object.prototype;
var hasOwn = Op.hasOwnProperty;
module.exports = function (fork) {
var types = fork.use(require("./types"));
var isArray = types.builtInTypes.array;
var isNumber = types.builtInTypes.number;
function Path(value, parentPath, name) {
if (!(this instanceof Path)) {
throw new Error("Path constructor cannot be invoked without 'new'");
}
if (parentPath) {
if (!(parentPath instanceof Path)) {
throw new Error("");
}
} else {
parentPath = null;
name = null;
}
// The value encapsulated by this Path, generally equal to
// parentPath.value[name] if we have a parentPath.
this.value = value;
// The immediate parent Path of this Path.
this.parentPath = parentPath;
// The name of the property of parentPath.value through which this
// Path's value was reached.
this.name = name;
// Calling path.get("child") multiple times always returns the same
// child Path object, for both performance and consistency reasons.
this.__childCache = null;
}
var Pp = Path.prototype;
function getChildCache(path) {
// Lazily create the child cache. This also cheapens cache
// invalidation, since you can just reset path.__childCache to null.
return path.__childCache || (path.__childCache = Object.create(null));
}
function getChildPath(path, name) {
var cache = getChildCache(path);
var actualChildValue = path.getValueProperty(name);
var childPath = cache[name];
if (!hasOwn.call(cache, name) ||
// Ensure consistency between cache and reality.
childPath.value !== actualChildValue) {
childPath = cache[name] = new path.constructor(
actualChildValue, path, name
);
}
return childPath;
}
// This method is designed to be overridden by subclasses that need to
// handle missing properties, etc.
Pp.getValueProperty = function getValueProperty(name) {
return this.value[name];
};
Pp.get = function get(name) {
var path = this;
var names = arguments;
var count = names.length;
for (var i = 0; i < count; ++i) {
path = getChildPath(path, names[i]);
}
return path;
};
Pp.each = function each(callback, context) {
var childPaths = [];
var len = this.value.length;
var i = 0;
// Collect all the original child paths before invoking the callback.
for (var i = 0; i < len; ++i) {
if (hasOwn.call(this.value, i)) {
childPaths[i] = this.get(i);
}
}
// Invoke the callback on just the original child paths, regardless of
// any modifications made to the array by the callback. I chose these
// semantics over cleverly invoking the callback on new elements because
// this way is much easier to reason about.
context = context || this;
for (i = 0; i < len; ++i) {
if (hasOwn.call(childPaths, i)) {
callback.call(context, childPaths[i]);
}
}
};
Pp.map = function map(callback, context) {
var result = [];
this.each(function (childPath) {
result.push(callback.call(this, childPath));
}, context);
return result;
};
Pp.filter = function filter(callback, context) {
var result = [];
this.each(function (childPath) {
if (callback.call(this, childPath)) {
result.push(childPath);
}
}, context);
return result;
};
function emptyMoves() {}
function getMoves(path, offset, start, end) {
isArray.assert(path.value);
if (offset === 0) {
return emptyMoves;
}
var length = path.value.length;
if (length < 1) {
return emptyMoves;
}
var argc = arguments.length;
if (argc === 2) {
start = 0;
end = length;
} else if (argc === 3) {
start = Math.max(start, 0);
end = length;
} else {
start = Math.max(start, 0);
end = Math.min(end, length);
}
isNumber.assert(start);
isNumber.assert(end);
var moves = Object.create(null);
var cache = getChildCache(path);
for (var i = start; i < end; ++i) {
if (hasOwn.call(path.value, i)) {
var childPath = path.get(i);
if (childPath.name !== i) {
throw new Error("");
}
var newIndex = i + offset;
childPath.name = newIndex;
moves[newIndex] = childPath;
delete cache[i];
}
}
delete cache.length;
return function () {
for (var newIndex in moves) {
var childPath = moves[newIndex];
if (childPath.name !== +newIndex) {
throw new Error("");
}
cache[newIndex] = childPath;
path.value[newIndex] = childPath.value;
}
};
}
Pp.shift = function shift() {
var move = getMoves(this, -1);
var result = this.value.shift();
move();
return result;
};
Pp.unshift = function unshift(node) {
var move = getMoves(this, arguments.length);
var result = this.value.unshift.apply(this.value, arguments);
move();
return result;
};
Pp.push = function push(node) {
isArray.assert(this.value);
delete getChildCache(this).length
return this.value.push.apply(this.value, arguments);
};
Pp.pop = function pop() {
isArray.assert(this.value);
var cache = getChildCache(this);
delete cache[this.value.length - 1];
delete cache.length;
return this.value.pop();
};
Pp.insertAt = function insertAt(index, node) {
var argc = arguments.length;
var move = getMoves(this, argc - 1, index);
if (move === emptyMoves) {
return this;
}
index = Math.max(index, 0);
for (var i = 1; i < argc; ++i) {
this.value[index + i - 1] = arguments[i];
}
move();
return this;
};
Pp.insertBefore = function insertBefore(node) {
var pp = this.parentPath;
var argc = arguments.length;
var insertAtArgs = [this.name];
for (var i = 0; i < argc; ++i) {
insertAtArgs.push(arguments[i]);
}
return pp.insertAt.apply(pp, insertAtArgs);
};
Pp.insertAfter = function insertAfter(node) {
var pp = this.parentPath;
var argc = arguments.length;
var insertAtArgs = [this.name + 1];
for (var i = 0; i < argc; ++i) {
insertAtArgs.push(arguments[i]);
}
return pp.insertAt.apply(pp, insertAtArgs);
};
function repairRelationshipWithParent(path) {
if (!(path instanceof Path)) {
throw new Error("");
}
var pp = path.parentPath;
if (!pp) {
// Orphan paths have no relationship to repair.
return path;
}
var parentValue = pp.value;
var parentCache = getChildCache(pp);
// Make sure parentCache[path.name] is populated.
if (parentValue[path.name] === path.value) {
parentCache[path.name] = path;
} else if (isArray.check(parentValue)) {
// Something caused path.name to become out of date, so attempt to
// recover by searching for path.value in parentValue.
var i = parentValue.indexOf(path.value);
if (i >= 0) {
parentCache[path.name = i] = path;
}
} else {
// If path.value disagrees with parentValue[path.name], and
// path.name is not an array index, let path.value become the new
// parentValue[path.name] and update parentCache accordingly.
parentValue[path.name] = path.value;
parentCache[path.name] = path;
}
if (parentValue[path.name] !== path.value) {
throw new Error("");
}
if (path.parentPath.get(path.name) !== path) {
throw new Error("");
}
return path;
}
Pp.replace = function replace(replacement) {
var results = [];
var parentValue = this.parentPath.value;
var parentCache = getChildCache(this.parentPath);
var count = arguments.length;
repairRelationshipWithParent(this);
if (isArray.check(parentValue)) {
var originalLength = parentValue.length;
var move = getMoves(this.parentPath, count - 1, this.name + 1);
var spliceArgs = [this.name, 1];
for (var i = 0; i < count; ++i) {
spliceArgs.push(arguments[i]);
}
var splicedOut = parentValue.splice.apply(parentValue, spliceArgs);
if (splicedOut[0] !== this.value) {
throw new Error("");
}
if (parentValue.length !== (originalLength - 1 + count)) {
throw new Error("");
}
move();
if (count === 0) {
delete this.value;
delete parentCache[this.name];
this.__childCache = null;
} else {
if (parentValue[this.name] !== replacement) {
throw new Error("");
}
if (this.value !== replacement) {
this.value = replacement;
this.__childCache = null;
}
for (i = 0; i < count; ++i) {
results.push(this.parentPath.get(this.name + i));
}
if (results[0] !== this) {
throw new Error("");
}
}
} else if (count === 1) {
if (this.value !== replacement) {
this.__childCache = null;
}
this.value = parentValue[this.name] = replacement;
results.push(this);
} else if (count === 0) {
delete parentValue[this.name];
delete this.value;
this.__childCache = null;
// Leave this path cached as parentCache[this.name], even though
// it no longer has a value defined.
} else {
throw new Error("Could not replace path");
}
return results;
};
return Path;
};