Finish chunked reader implementation

net/http/transport.ha

@@ -1,5 +1,6 @@
 use errors;
 use bufio;
+use bytes;
 use io;
 use os;
 use strconv;
@@ -90,10 +91,9 @@ fn new_reader(
 
 		// XXX: We could add lzw support if someone added it to
 		// hare-compress
-		switch (te) {
+		const next = switch (te) {
 		case "chunked" =>
-			stream = new_chunked_reader(stream, buffer);
-			buffer = [];
+			yield new_chunked_reader(stream, buffer);
 		case "deflate" =>
 			abort(); // TODO
 		case "gzip" =>
@@ -101,6 +101,9 @@ fn new_reader(
 		case =>
 			return errors::unsupported;
 		};
+		stream = next;
+
+		buffer = [];
 	};
 
 	if (!(stream is *io::stream)) {
@@ -177,13 +180,20 @@ fn identity_read(
 	return n;
 };
 
+type chunk_state = enum {
+	HEADER,
+	DATA,
+	FOOTER,
+};
+
 type chunked_reader = struct {
 	vtable: io::stream,
 	conn: io::handle,
 	buffer: [os::BUFSIZ]u8,
+	state: chunk_state,
 	// Amount of read-ahead data in buffer
 	pending: size,
-	// Length of current chunk, or zero
+	// Length of current chunk
 	length: size,
 };
 
@@ -210,5 +220,100 @@ fn chunked_read(
 	s: *io::stream,
 	buf: []u8,
 ) (size | io::EOF | io::error) = {
-	abort(); // TODO
+	// XXX: I am not satisfied with this code
+	let rd = s: *chunked_reader;
+	assert(rd.vtable == &chunked_reader_vtable);
+
+	for (true) switch (rd.state) {
+	case chunk_state::HEADER =>
+		let crlf = 0z;
+		for (true) {
+			const n = rd.pending;
+			match (bytes::index(rd.buffer[..n], ['\r', '\n'])) {
+			case let z: size =>
+				crlf = z;
+				break;
+			case void =>
+				yield;
+			};
+			if (rd.pending >= len(rd.buffer)) {
+				// Chunk header exceeds buffer size
+				return errors::overflow;
+			};
+
+			match (io::read(rd.conn, rd.buffer[rd.pending..])?) {
+			case let n: size =>
+				rd.pending += n;
+			case io::EOF =>
+				if (rd.pending > 0) {
+					return errors::invalid;
+				};
+				return io::EOF;
+			};
+		};
+
+		// XXX: Should we do anything with chunk-ext?
+		const header = rd.buffer[..crlf];
+		const (ln, _) = bytes::cut(header, ';');
+		const ln = match (strings::fromutf8(ln)) {
+		case let s: str =>
+			yield s;
+		case =>
+			return errors::invalid;
+		};
+
+		match (strconv::stozb(ln, strconv::base::HEX)) {
+		case let z: size =>
+			rd.length = z;
+		case =>
+			return errors::invalid;
+		};
+		if (rd.length == 0) {
+			return io::EOF;
+		};
+
+		const n = crlf + 2;
+		rd.buffer[..rd.pending - n] = rd.buffer[n..rd.pending];
+		rd.pending -= n;
+		rd.state = chunk_state::DATA;
+	case chunk_state::DATA =>
+		if (rd.pending == 0) {
+			match (io::read(rd.conn, rd.buffer)?) {
+			case let n: size =>
+				rd.pending += n;
+			case io::EOF =>
+				return io::EOF;
+			};
+		};
+		let n = len(buf);
+		if (n > rd.pending) {
+			n = rd.pending;
+		};
+		if (n > rd.length) {
+			n = rd.length;
+		};
+		buf[..n] = rd.buffer[..n];
+		rd.buffer[..rd.pending - n] = rd.buffer[n..rd.pending];
+		rd.pending -= n;
+		rd.length -= n;
+		rd.state = chunk_state::FOOTER;
+		return n;
+	case chunk_state::FOOTER =>
+		for (rd.pending < 2) {
+			match (io::read(rd.conn, rd.buffer[rd.pending..])?) {
+			case let n: size =>
+				rd.pending += n;
+			case io::EOF =>
+				return io::EOF;
+			};
+		};
+		if (!bytes::equal(rd.buffer[..2], ['\r', '\n'])) {
+			return errors::invalid;
+		};
+		rd.buffer[..rd.pending - 2] = rd.buffer[2..rd.pending];
+		rd.pending -= 2;
+		rd.state = chunk_state::HEADER;
+	};
+
+	abort(); // Unreachable
 };