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Maintain a queue to allow deletion of whitespace/semicolons without accessing buf.

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This commit is contained in:
Logan Smyth 2016-07-05 20:05:33 -07:00
parent cb60808500
commit 65a677decd
1 changed files with 51 additions and 27 deletions
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78
packages/babel-generator/src/buffer.js
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@ -2,6 +2,8 @@ import Position from "./position";
import type SourceMap from "./source-map";
import trimEnd from "lodash/trimEnd";
const SPACES_RE = /^[ \t]+$/;
/**
* The Buffer class exists to manage the queue of tokens being pushed onto the output string
* in such a way that the final string buffer is treated as write-only until the final .get()
@ -31,6 +33,8 @@ export default class Buffer {
*/
get(): Object {
this._flush();
return {
code: trimEnd(this._buf),
map: this._map ? this._map.get() : null,
@ -42,13 +46,9 @@ export default class Buffer {
*/
append(str: string): void {
// If there the line is ending, adding a new mapping marker is redundant
if (this._map && str[0] !== "\n") this._map.mark(this._position, this._sourcePosition.line,
this._sourcePosition.column, this._sourcePosition.filename);
this._buf += str;
this._last = str[str.length - 1];
this._position.push(str);
this._flush();
this._append(str, this._sourcePosition.line, this._sourcePosition.column,
this._sourcePosition.filename);
}
/**
@ -56,44 +56,58 @@ export default class Buffer {
*/
queue(str: string): void {
this.append(str);
this._queue.unshift([str, this._sourcePosition.line, this._sourcePosition.column,
this._sourcePosition.filename]);
}
_flush(): void {
let item;
while (item = this._queue.pop()) this._append(...item);
}
_append(str: string, line: number, column: number, filename: ?string): void {
// If there the line is ending, adding a new mapping marker is redundant
if (this._map && str[0] !== "\n") this._map.mark(this._position, line, column, filename);
this._buf += str;
this._last = str[str.length - 1];
this._position.push(str);
}
removeTrailingSpaces(): void {
const oldBuf = this._buf;
this._buf = this._buf.replace(/[ \t]+$/, "");
this._last = this._buf[this._buf.length - 1];
this._position.unshift(oldBuf.slice(this._buf.length));
while (this._queue.length > 0 && SPACES_RE.test(this._queue[0][0])) this._queue.shift();
}
removeTrailingNewline(): void {
if (this._last !== "\n") return;
this._buf = this._buf.slice(0, -1);
this._last = this._buf[this._buf.length - 1];
this._position.unshift("\n");
if (this._queue.length > 0 && this._queue[0][0] === "\n") this._queue.shift();
}
removeLastSemicolon(): void {
if (this._last !== ";") return;
this._buf = this._buf.slice(0, -1);
this._last = this._buf[this._buf.length - 1];
this._position.unshift(";");
if (this._queue.length > 0 && this._queue[0][0] === ";") this._queue.shift();
}
endsWith(str: string): boolean {
if (str.length === 1) return str === this._last;
const end = this._last + this._queue.reduce((acc, item) => item[0] + acc, "");
if (str.length <= end.length) {
return end.slice(-str.length) === str;
}
return this._buf.slice(-str.length) === str;
// We assume that everything being matched is at most a single token plus some whitespace,
// which everything currently is, but otherwise we'd have to expand _last or check _buf.
return false;
}
getLast(): string {
if (this._queue.length > 0) {
const last = this._queue[this._queue.length - 1][0];
return last[last.length - 1];
}
return this._last;
}
hasContent(): boolean {
return !!this._last;
return this._queue.length > 0 || !!this._last;
}
/**
@ -133,10 +147,20 @@ export default class Buffer {
}
getCurrentColumn(): number {
return this._position.column;
const extra = this._queue.reduce((acc, item) => item[0] + acc, "");
const lastIndex = extra.lastIndexOf("\n");
return lastIndex === -1 ? this._position.column + extra.length : (extra.length - 1 - lastIndex);
}
getCurrentLine(): number {
return this._position.line;
const extra = this._queue.reduce((acc, item) => item[0] + acc, "");
let count = 0;
for (let i = 0; i < extra.length; i++) {
if (extra[i] === "\n") count++;
}
return this._position.line + count;
}
}