Hojun-Cho
2243849855
Five tags from ref/hare/errors/common.ha — invalid, noaccess, noentry, exists, unsupported — all !void. lib/io keeps eof/closed as plain void (no Hare analogue for ww's singleton-style done) and adds underread. Drops errors.equal/isnil and the old str-sentinel surface.
43 lines
1.4 KiB
Plaintext
43 lines
1.4 KiB
Plaintext
// io — stream interface (Plan 9 Bio / Hare io::stream shape).
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//
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// No closures, no methods. A `stream` is a struct of function
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// pointers plus a `ctx: *void`. The error channel is the return
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// value of read/write/close — Hare-shaped tagged unions instead of
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// errno-style integer sentinels.
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// eof — read past the end of the stream. Hare uses the `done`
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// singleton for EOF; ww doesn't have `done` yet so we ship a
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// named-void variant tag.
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export type eof = void;
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// closed — operation attempted on a stream that has already been
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// closed. ww-specific: Hare's io collapses this into the wider
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// errors union, but our stream vtable has no handle-ownership
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// semantics, so a distinct tag is honest. Named void.
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export type closed = void;
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// underread — an I/O handle hit eof partway through a fixed-size
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// read. Payload is the byte count actually delivered. Mirrors
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// Hare's `io::underread = !size`; ww uses i32 because the
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// underlying buffer-length type is i32 today.
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export type underread = !i32;
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export type stream = struct {
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ctx: *void,
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read: fn(s: *stream, buf: []u8) (i32 | eof | closed),
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write: fn(s: *stream, buf: []u8) (i32 | closed),
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close: fn(s: *stream) (void | closed),
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};
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export fn read(s: *stream, buf: []u8) (i32 | eof | closed) = {
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return s.read(s, buf);
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};
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export fn write(s: *stream, buf: []u8) (i32 | closed) = {
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return s.write(s, buf);
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};
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export fn close(s: *stream) (void | closed) = {
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return s.close(s);
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};
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