X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2F_info;h=8f5c2adc3008fc58bfb4758331a9eb56e7812636;hp=d596b4deb11d401b40b3d2210eab80c8ceedff69;hb=b7e880755a5fad76f876bec31d6eabd0c5284151;hpb=1fe2db9cbe84812e1465db36f538a222e9984c93

diff --git a/ccan/io/_info b/ccan/io/_info
index d596b4de..8f5c2adc 100644
--- a/ccan/io/_info
+++ b/ccan/io/_info
@@ -3,12 +3,18 @@
 #include "config.h"
 
 /**
- * io - simple library for stateful io handling.
+ * io - simple library for asynchronous io handling.
  *
- * io provides a simple mechanism to write I/O servers with multiple
- * connections.  Handling of connections is multiplexed, and function
- * indicate what they want written or read, and what follow-on
- * function to call on success (or failure).
+ * io provides a mechanism to write I/O servers with multiple
+ * connections.  Each callback indicates what I/O they plan next
+ * (eg. read, write).  It is also possible to write custom I/O
+ * plans.
+ *
+ * When compiled with DEBUG, control flow is changed so that rather
+ * than returning to the main io_loop(), plans are executed sequentially
+ * providing a backtrace showing what has occurred on that connection.
+ * Which connection(s) do this depends on the user-specified io_debug
+ * function.
  *
  * Example:
  * // Given tr A-Z a-z outputs tr a-z a-z
@@ -19,104 +25,74 @@
  * #include <signal.h>
  * #include <sys/types.h>
  * #include <sys/wait.h>
+ * #include <string.h>
  *
  * struct buffer {
- * 	size_t max, off, rlen;
- * 	char *buf;
- * };
- *
- * struct stdin_buffer {
- * 	struct io_conn *reader, *writer;
- * 	size_t len;
- * 	char inbuf[4096];
+ * 	bool finished;
+ * 	size_t start, end, rlen, wlen;
+ * 	char buf[4096];
  * };
  *
- * // This reads from stdin.
- * static struct io_op *wake_writer(struct io_conn *, struct stdin_buffer *);
- * // This writes the stdin buffer to the child.
- * static struct io_op *write_to_child(struct io_conn *c,
- * 				       struct stdin_buffer *b);
- * static struct io_op *read_stdin(struct io_conn *c, struct stdin_buffer *b)
+ * static void finish(struct io_conn *c, struct buffer *b)
  * {
- * 	assert(c == b->reader);
- * 	b->len = sizeof(b->inbuf);
- * 	return io_read_partial(b->inbuf, &b->len,
- *			       io_next(c, wake_writer, b));
+ * 	// Mark us finished.
+ * 	b->finished = true;
+ * 	// Wake writer just in case it's asleep.
+ * 	io_wake(b);
  * }
  *
- * static struct io_op *wake_writer(struct io_conn *c, struct stdin_buffer *b)
+ * static struct io_plan read_in(struct io_conn *c, struct buffer *b)
  * {
- * 	assert(c == b->reader);
- * 	io_wake(b->writer, write_to_child, b);
- * 	return io_idle(c);
- * }
+ * 	// Add what we just read.
+ * 	b->end += b->rlen;
+ * 	assert(b->end <= sizeof(b->buf));
  *
- * static void reader_exit(struct io_conn *c, struct stdin_buffer *b)
- * {
- * 	assert(c == b->reader);
- * 	io_wake(b->writer, write_to_child, b);
- * 	b->reader = NULL;
- * }
+ * 	// If we just read something, wake writer.
+ * 	if (b->rlen != 0)
+ * 		io_wake(b);
  *
- * static struct io_op *wake_reader(struct io_conn *c, struct stdin_buffer *b)
- * {
- * 	assert(c == b->writer);
- * 	io_wake(b->reader, read_stdin, b);
- * 	return io_idle(c);
- * }
+ * 	// If buffer is empty, return to start.
+ * 	if (b->start == b->end)
+ * 		b->start = b->end = 0;
  *
- * static struct io_op *write_to_child(struct io_conn *conn,
- * 				      struct stdin_buffer *b)
- * {
- * 	assert(conn == b->writer);
- * 	if (!b->reader)
- * 		return io_close(conn, NULL);
- * 	return io_write(b->inbuf, b->len, io_next(conn, wake_reader, b));
- * }
+ * 	// Read in some of the rest.
+ * 	b->rlen = sizeof(b->buf) - b->end;
  *
- * static struct io_op *start_writer(struct io_conn *conn,
- * 				     struct stdin_buffer *b)
- * {
- * 	assert(conn == b->writer);
- * 	return io_idle(conn);
- * }
+ * 	// No room?  Wait for writer
+ * 	if (b->rlen == 0)
+ * 		return io_wait(b, read_in, b);
  *
- * static void fail_child_write(struct io_conn *conn, struct stdin_buffer *b)
- * {
- * 	if (b->reader)
- * 		err(1, "Failed writing to child.");
+ * 	return io_read_partial(b->buf + b->end, &b->rlen, read_in, b);
  * }
  *
- * // This reads from the child and saves it into buffer.
- * static struct io_op *read_from_child(struct io_conn *conn,
- * 				        struct buffer *b)
+ * static struct io_plan write_out(struct io_conn *c, struct buffer *b)
  * {
- * 	b->off += b->rlen;
- *
- * 	if (b->off == b->max) {
- * 		if (b->max == 0)
- * 			b->max = 128;
- * 		else if (b->max >= 1024*1024)
- * 			b->max += 1024*1024;
- * 		else
- * 			b->max *= 2;
- * 		b->buf = realloc(b->buf, b->max);
+ * 	// Remove what we just wrote.
+ * 	b->start += b->wlen;
+ * 	assert(b->start <= sizeof(b->buf));
+ *
+ * 	// If we wrote somthing, wake writer.
+ * 	if (b->wlen != 0)
+ * 		io_wake(b);
+ *
+ * 	b->wlen = b->end - b->start;
+ * 	// Nothing to write?  Wait for reader.
+ * 	if (b->wlen == 0) {
+ * 		if (b->finished)
+ * 			return io_close();
+ * 		return io_wait(b, write_out, b);
  * 	}
  *
- * 	b->rlen = b->max - b->off;
- * 	return io_read_partial(b->buf + b->off, &b->rlen,
- *			       io_next(conn, read_from_child, b));
+ * 	return io_write_partial(b->buf + b->start, &b->wlen, write_out, b);
  * }
  *
  * // Feed a program our stdin, gather its stdout, print that at end.
  * int main(int argc, char *argv[])
  * {
  * 	int tochild[2], fromchild[2];
- * 	struct buffer out = { 0, 0, 0, NULL };
- * 	struct stdin_buffer sbuf;
+ * 	struct buffer to, from;
  * 	int status;
- * 	size_t off;
- * 	ssize_t ret;
+ * 	struct io_conn *reader;
  *
  * 	if (argc == 1)
  * 		errx(1, "Usage: runner <cmdline>...");
@@ -139,23 +115,20 @@
  * 	close(fromchild[1]);
  * 	signal(SIGPIPE, SIG_IGN);
  *
- * 	sbuf.reader = io_new_conn(STDIN_FILENO, read_stdin, reader_exit, &sbuf);
- * 	sbuf.writer = io_new_conn(tochild[1], start_writer, fail_child_write,
- * 				  &sbuf);
- * 	if (!sbuf.reader || !sbuf.writer
- * 	    || !io_new_conn(fromchild[0], read_from_child, NULL, &out))
- * 		err(1, "Allocating connections");
+ * 	// Read from stdin, write to child.
+ * 	memset(&to, 0, sizeof(to));
+ * 	reader = io_new_conn(STDIN_FILENO, read_in(NULL, &to));
+ * 	io_set_finish(reader, finish, &to);
+ * 	io_new_conn(tochild[1], write_out(NULL, &to));
+ *
+ * 	// Read from child, write to stdout.
+ * 	reader = io_new_conn(fromchild[0], read_in(NULL, &from));
+ * 	io_set_finish(reader, finish, &from);
+ * 	io_new_conn(STDOUT_FILENO, write_out(NULL, &from));
  *
  * 	io_loop();
  * 	wait(&status);
  *
- * 	for (off = 0; off < out.off; off += ret) {
- * 		ret = write(STDOUT_FILENO, out.buf+off, out.off-off);
- * 		if (ret < 0)
- * 			err(1, "Writing stdout");
- * 	}
- * 	free(out.buf);
- *
  * 	return WIFEXITED(status) ? WEXITSTATUS(status) : 2;
  * }
  *
@@ -168,6 +141,7 @@ int main(int argc, char *argv[])
 		return 1;
 
 	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/typesafe_cb\n");
 		printf("ccan/time\n");
 		printf("ccan/timer\n");
 		return 0;