zipsink.ts is the sink of the page for a format 3 capsule (design of
format 3, section 5). Its files go to the temporary file of OPFS: the
file itself when the capsule holds one file of one segment, and
otherwise a ZIP of stored entries laid out from the head before any
byte arrives. Each local header is written at its offset, the bytes of
the file follow as open delivers them, the CRC-32 of the entry is
patched in its header with a positioned write, and commit writes the
central directory and closes the file; abort discards it, also when
the opening failed before begin. Each file is a contiguous range of the
file written (ranges), and zipOf makes the same ZIP in memory as a Blob
of its parts.
tempfile.ts: the writable of a temporary file takes TempChunk, bytes at
the position of the file or at a given one, as
FileSystemWritableFileStream does; cancellable is generic.
Interoperability: scripts/zip-ts-samples.mjs writes the samples of
testing/zip.ts with ZipSink, and scripts/zip-go-read.go reads them with
archive/zip of the Go standard library: names out of ASCII with bit 11,
stored entries, their CRC-32 and sizes, the times of the extra fields
in 1970, at 2^31 - 1 and after it, in 9999 and the time of the round for
a file without one, and 65535 entries, ZIP64 by their number. The
reading is frozen in testing/zip-vectors.json, and zipsink.test.ts
writes each sample again, requires its SHA-256 and computes the entries
Go must have read. zipsink.ts is covered at 100 %.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
