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Honor backpressure during ZIP finalization #227

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97 changes: 55 additions & 42 deletions lib/archivers/zip/zip-archive-output-stream.js
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Original file line number Diff line number Diff line change
Expand Up @@ -47,12 +47,14 @@ export default class ZipArchiveOutputStream extends ArchiveOutputStream {
this.options = _options;
this._entry = null;
this._entries = [];
this._centralDirectoryIndex = 0;
this._archive = {
centralLength: 0,
centralOffset: 0,
comment: "",
finish: false,
finished: false,
finalizing: false,
processing: false,
forceZip64: _options.forceZip64,
forceLocalTime: _options.forceLocalTime,
Expand Down Expand Up @@ -109,20 +111,36 @@ export default class ZipArchiveOutputStream extends ArchiveOutputStream {
}

_finish() {
if (this._archive.finalizing || this._archive.finished) {
return;
}
this._archive.centralOffset = this.offset;
this._entries.forEach(
function (ae) {
this._writeCentralFileHeader(ae);
}.bind(this),
);
this._archive.finalizing = true;
this._archive.finish = true;
this._centralDirectoryIndex = 0;
this._writeCentralDirectory();
}

_writeCentralDirectory() {
while (this._centralDirectoryIndex < this._entries.length) {
var index = this._centralDirectoryIndex;
var ae = this._entries[index];
this._entries[index] = undefined;
this._centralDirectoryIndex += 1;
if (!this._writeCentralFileHeader(ae)) {
this.once("drain", this._writeCentralDirectory.bind(this));
return;
}
}
this._archive.centralLength = this.offset - this._archive.centralOffset;
if (this.isZip64()) {
this._writeCentralDirectoryZip64();
}
this._writeCentralDirectoryEnd();
this._archive.processing = false;
this._archive.finish = true;
this._archive.finalizing = false;
this._archive.finished = true;
this._entries = [];
this.end();
}

Expand Down Expand Up @@ -248,49 +266,44 @@ export default class ZipArchiveOutputStream extends ArchiveOutputStream {
);
ae.setExtra(extraBuf);
}
// signature
this.write(getLongBytes(SIG_CFH));
// version made by
this.write(getShortBytes((ae.getPlatform() << 8) | VERSION_MADEBY));
// version to extract and general bit flag
this.write(getShortBytes(ae.getVersionNeededToExtract()));
this.write(gpb.encode());
// compression method
this.write(getShortBytes(method));
// datetime
this.write(getLongBytes(ae.getTimeDos()));
// crc32 checksum
this.write(getLongBytes(ae.getCrc()));
// sizes
this.write(getLongBytes(compressedSize));
this.write(getLongBytes(size));
var name = ae.getName();
var comment = ae.getComment();
var extra = ae.getCentralDirectoryExtra();
if (gpb.usesUTF8ForNames()) {
name = Buffer.from(name);
comment = Buffer.from(comment);
}
// name length
this.write(getShortBytes(name.length));
// extra length
this.write(getShortBytes(extra.length));
// comments length
this.write(getShortBytes(comment.length));
// disk number start
this.write(SHORT_ZERO);
// internal attributes
this.write(getShortBytes(ae.getInternalAttributes()));
// external attributes
this.write(getLongBytes(ae.getExternalAttributes()));
// relative offset of LFH
this.write(getLongBytes(fileOffset));
// name
this.write(name);
// extra
this.write(extra);
// comment
this.write(comment);
if (!Buffer.isBuffer(name)) {
name = Buffer.from(name);
}
if (!Buffer.isBuffer(comment)) {
comment = Buffer.from(comment);
}
var header = Buffer.concat(
[
getLongBytes(SIG_CFH),
getShortBytes((ae.getPlatform() << 8) | VERSION_MADEBY),
getShortBytes(ae.getVersionNeededToExtract()),
gpb.encode(),
getShortBytes(method),
getLongBytes(ae.getTimeDos()),
getLongBytes(ae.getCrc()),
getLongBytes(compressedSize),
getLongBytes(size),
getShortBytes(name.length),
getShortBytes(extra.length),
getShortBytes(comment.length),
SHORT_ZERO,
getShortBytes(ae.getInternalAttributes()),
getLongBytes(ae.getExternalAttributes()),
getLongBytes(fileOffset),
name,
extra,
comment,
],
46 + name.length + extra.length + comment.length,
);
return this.write(header);
}

_writeDataDescriptor(ae) {
Expand Down
79 changes: 79 additions & 0 deletions test/zip-archive-output-stream.js
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Original file line number Diff line number Diff line change
Expand Up @@ -120,5 +120,84 @@ describe("ZipArchiveOutputStream", function () {
archive.pipe(testStream);
archive.entry(entry, createReadStream("test/fixtures/test.txt")).finish();
});
it("should honor backpressure while writing the central directory", function (done) {
this.timeout(10000);
var entryCount = 2000;
var archive = new BackpressureZipArchiveOutputStream();
var chunks = [];
archive.on("data", function (chunk) {
chunks.push(chunk);
});
archive.on("end", function () {
var output = Buffer.concat(chunks);
var names = getCentralDirectoryNames(output);
assert.equal(archive.centralDirectoryWrites, entryCount);
assert.equal(archive.drainEvents, entryCount);
assert.lengthOf(names, entryCount);
assert.equal(names[0], "entry-0.txt");
assert.equal(
names[entryCount - 1],
"entry-" + (entryCount - 1) + ".txt",
);
done();
});
for (var i = 0; i < entryCount; i++) {
var entry = new ZipArchiveEntry("entry-" + i + ".txt");
archive.entry(entry, Buffer.alloc(0));
}
archive.finish();
});
});
});

class BackpressureZipArchiveOutputStream extends ZipArchiveOutputStream {
constructor() {
super();
this.centralDirectoryWrites = 0;
this.drainEvents = 0;
this.waitingForDrain = false;
}

write(chunk, callback) {
var isCentralDirectoryHeader =
Buffer.isBuffer(chunk) &&
chunk.length >= 4 &&
chunk.readUInt32LE(0) === 0x02014b50;
if (!isCentralDirectoryHeader) {
return super.write(chunk, callback);
}
assert.isFalse(this.waitingForDrain);
super.write(chunk, callback);
this.centralDirectoryWrites += 1;
this.waitingForDrain = true;
setImmediate(
function () {
this.waitingForDrain = false;
this.drainEvents += 1;
this.emit("drain");
}.bind(this),
);
return false;
}
}

function getCentralDirectoryNames(output) {
var endSignature = Buffer.from([0x50, 0x4b, 0x05, 0x06]);
var endOffset = output.lastIndexOf(endSignature);
assert.isAtLeast(endOffset, 0);
var entryCount = output.readUInt16LE(endOffset + 10);
var centralLength = output.readUInt32LE(endOffset + 12);
var centralOffset = output.readUInt32LE(endOffset + 16);
var offset = centralOffset;
var names = [];
for (var i = 0; i < entryCount; i++) {
assert.equal(output.readUInt32LE(offset), 0x02014b50);
var nameLength = output.readUInt16LE(offset + 28);
var extraLength = output.readUInt16LE(offset + 30);
var commentLength = output.readUInt16LE(offset + 32);
names.push(output.toString("utf8", offset + 46, offset + 46 + nameLength));
offset += 46 + nameLength + extraLength + commentLength;
}
assert.equal(offset, centralOffset + centralLength);
return names;
}