/**
* @fileoverview Attaches comments to the AST.
* @author Nicholas C. Zakas
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
var astNodeTypes = require("./ast-node-types");
//------------------------------------------------------------------------------
// Private
//------------------------------------------------------------------------------
var extra = {
trailingComments: [],
leadingComments: [],
bottomRightStack: [],
previousNode: null
};
//------------------------------------------------------------------------------
// Public
//------------------------------------------------------------------------------
module.exports = {
reset: function() {
extra.trailingComments = [];
extra.leadingComments = [];
extra.bottomRightStack = [];
extra.previousNode = null;
},
addComment: function(comment) {
extra.trailingComments.push(comment);
extra.leadingComments.push(comment);
},
processComment: function(node) {
var lastChild,
trailingComments,
i,
j;
if (node.type === astNodeTypes.Program) {
if (node.body.length > 0) {
return;
}
}
if (extra.trailingComments.length > 0) {
/*
* If the first comment in trailingComments comes after the
* current node, then we're good - all comments in the array will
* come after the node and so it's safe to add then as official
* trailingComments.
*/
if (extra.trailingComments[0].range[0] >= node.range[1]) {
trailingComments = extra.trailingComments;
extra.trailingComments = [];
} else {
/*
* Otherwise, if the first comment doesn't come after the
* current node, that means we have a mix of leading and trailing
* comments in the array and that leadingComments contains the
* same items as trailingComments. Reset trailingComments to
* zero items and we'll handle this by evaluating leadingComments
* later.
*/
extra.trailingComments.length = 0;
}
} else {
if (extra.bottomRightStack.length > 0 &&
extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments &&
extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments[0].range[0] >= node.range[1]) {
trailingComments = extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments;
delete extra.bottomRightStack[extra.bottomRightStack.length - 1].trailingComments;
}
}
// Eating the stack.
while (extra.bottomRightStack.length > 0 && extra.bottomRightStack[extra.bottomRightStack.length - 1].range[0] >= node.range[0]) {
lastChild = extra.bottomRightStack.pop();
}
if (lastChild) {
if (lastChild.leadingComments) {
if (lastChild.leadingComments[lastChild.leadingComments.length - 1].range[1] <= node.range[0]) {
node.leadingComments = lastChild.leadingComments;
delete lastChild.leadingComments;
} else {
// A leading comment for an anonymous class had been stolen by its first MethodDefinition,
// so this takes back the leading comment.
// See Also: https://github.com/eslint/espree/issues/158
for (i = lastChild.leadingComments.length - 2; i >= 0; --i) {
if (lastChild.leadingComments[i].range[1] <= node.range[0]) {
node.leadingComments = lastChild.leadingComments.splice(0, i + 1);
break;
}
}
}
}
} else if (extra.leadingComments.length > 0) {
if (extra.leadingComments[extra.leadingComments.length - 1].range[1] <= node.range[0]) {
if (extra.previousNode) {
for (j = 0; j < extra.leadingComments.length; j++) {
if (extra.leadingComments[j].end < extra.previousNode.end) {
extra.leadingComments.splice(j, 1);
j--;
}
}
}
if (extra.leadingComments.length > 0) {
node.leadingComments = extra.leadingComments;
extra.leadingComments = [];
}
} else {
// https://github.com/eslint/espree/issues/2
/*
* In special cases, such as return (without a value) and
* debugger, all comments will end up as leadingComments and
* will otherwise be eliminated. This extra step runs when the
* bottomRightStack is empty and there are comments left
* in leadingComments.
*
* This loop figures out the stopping point between the actual
* leading and trailing comments by finding the location of the
* first comment that comes after the given node.
*/
for (i = 0; i < extra.leadingComments.length; i++) {
if (extra.leadingComments[i].range[1] > node.range[0]) {
break;
}
}
/*
* Split the array based on the location of the first comment
* that comes after the node. Keep in mind that this could
* result in an empty array, and if so, the array must be
* deleted.
*/
node.leadingComments = extra.leadingComments.slice(0, i);
if (node.leadingComments.length === 0) {
delete node.leadingComments;
}
/*
* Similarly, trailing comments are attached later. The variable
* must be reset to null if there are no trailing comments.
*/
trailingComments = extra.leadingComments.slice(i);
if (trailingComments.length === 0) {
trailingComments = null;
}
}
}
extra.previousNode = node;
if (trailingComments) {
node.trailingComments = trailingComments;
}
extra.bottomRightStack.push(node);
}
};