mirror of https://gitee.com/openkylin/nodejs.git
92 lines
2.2 KiB
JavaScript
92 lines
2.2 KiB
JavaScript
'use strict';
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require('../common');
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const assert = require('assert');
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const stream = require('stream');
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const Writable = stream.Writable;
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// Test the buffering behavior of Writable streams.
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//
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// The call to cork() triggers storing chunks which are flushed
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// on calling end() and the stream subsequently ended.
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//
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// node version target: 0.12
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const expectedChunks = ['please', 'buffer', 'me', 'kindly'];
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const inputChunks = expectedChunks.slice(0);
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let seenChunks = [];
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let seenEnd = false;
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const w = new Writable();
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// Let's arrange to store the chunks.
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w._write = function(chunk, encoding, cb) {
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// Stream end event is not seen before the last write.
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assert.ok(!seenEnd);
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// Default encoding given none was specified.
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assert.strictEqual(encoding, 'buffer');
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seenChunks.push(chunk);
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cb();
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};
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// Let's record the stream end event.
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w.on('finish', () => {
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seenEnd = true;
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});
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function writeChunks(remainingChunks, callback) {
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const writeChunk = remainingChunks.shift();
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let writeState;
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if (writeChunk) {
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setImmediate(() => {
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writeState = w.write(writeChunk);
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// We were not told to stop writing.
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assert.ok(writeState);
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writeChunks(remainingChunks, callback);
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});
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} else {
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callback();
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}
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}
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// Do an initial write.
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w.write('stuff');
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// The write was immediate.
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assert.strictEqual(seenChunks.length, 1);
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// Reset the seen chunks.
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seenChunks = [];
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// Trigger stream buffering.
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w.cork();
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// Write the bufferedChunks.
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writeChunks(inputChunks, () => {
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// Should not have seen anything yet.
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assert.strictEqual(seenChunks.length, 0);
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// Trigger flush and ending the stream.
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w.end();
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// Stream should not ended in current tick.
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assert.ok(!seenEnd);
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// Buffered bytes should be seen in current tick.
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assert.strictEqual(seenChunks.length, 4);
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// Did the chunks match.
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for (let i = 0, l = expectedChunks.length; i < l; i++) {
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const seen = seenChunks[i];
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// There was a chunk.
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assert.ok(seen);
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const expected = Buffer.from(expectedChunks[i]);
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// It was what we expected.
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assert.ok(seen.equals(expected));
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}
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setImmediate(() => {
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// Stream should have ended in next tick.
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assert.ok(seenEnd);
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});
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});
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