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cleanup: easier to read loop code

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buffer_write now accepts const pointer
Simplify loops and drop goto when not needed.
This commit is contained in:
Zdenek Kabelac 2013-06-18 11:59:22 +02:00
parent 155841c349
commit c5957ee2ff
2 changed files with 29 additions and 38 deletions
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65
libdaemon/client/daemon-io.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2011-2012 Red Hat, Inc.
* Copyright (C) 2011-2013 Red Hat, Inc.
*
* This file is part of LVM2.
*
@ -29,34 +29,32 @@
* See also write_buffer about blocking (read_buffer has identical behaviour).
*/
int buffer_read(int fd, struct buffer *buffer) {
int result;
if (!buffer_realloc(buffer, 32)) /* ensure we have some space */
goto fail;
return 0;
while (1) {
int result = read(fd, buffer->mem + buffer->used, buffer->allocated - buffer->used);
result = read(fd, buffer->mem + buffer->used, buffer->allocated - buffer->used);
if (result > 0) {
buffer->used += result;
if (!strncmp((buffer->mem) + buffer->used - 4, "\n##\n", 4)) {
*(buffer->mem + buffer->used - 4) = 0;
buffer->used -= 4;
buffer->mem[buffer->used] = 0;
break; /* success, we have the full message now */
}
if (buffer->allocated - buffer->used < 32)
if (!buffer_realloc(buffer, 1024))
goto fail;
continue;
}
if (result == 0) {
if ((buffer->allocated - buffer->used < 32) &&
!buffer_realloc(buffer, 1024))
return 0;
} else if (result == 0) {
errno = ECONNRESET;
goto fail; /* we should never encounter EOF here */
}
if (result < 0 && errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR)
goto fail;
return 0; /* we should never encounter EOF here */
} else if (result < 0 && errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR)
return 0;
/* TODO call select here if we encountered EAGAIN/EWOULDBLOCK/EINTR */
}
return 1;
fail:
return 0;
}
/*
@ -65,28 +63,21 @@ fail:
*
* TODO use select on EWOULDBLOCK/EAGAIN/EINTR to avoid useless spinning
*/
int buffer_write(int fd, struct buffer *buffer) {
struct buffer terminate = { .mem = (char *) "\n##\n", .used = 4 };
int done = 0;
int written = 0;
struct buffer *use = buffer;
write:
while (1) {
int result = write(fd, use->mem + written, use->used - written);
if (result > 0)
written += result;
if (result < 0 && errno != EWOULDBLOCK && errno != EAGAIN && errno != EINTR)
return 0; /* too bad */
if (written == use->used) {
if (done)
return 1;
else
break; /* done */
int buffer_write(int fd, const struct buffer *buffer) {
static const struct buffer _terminate = { .mem = (char *) "\n##\n", .used = 4 };
const struct buffer *use;
int done, written, result;
for (done = 0; done < 2; ++done) {
use = (done == 0) ? buffer : &_terminate;
for (written = 0; written < use->used;) {
result = write(fd, use->mem + written, use->used - written);
if (result > 0)
written += result;
else if (result < 0 && errno != EWOULDBLOCK && errno != EAGAIN && errno != EINTR)
return 0; /* too bad */
}
}
use = &terminate;
written = 0;
done = 1;
goto write;
return 1;
}

2
libdaemon/client/daemon-io.h
View File

@ -26,6 +26,6 @@
/* TODO function names */
int buffer_read(int fd, struct buffer *buffer);
int buffer_write(int fd, struct buffer *buffer);
int buffer_write(int fd, const struct buffer *buffer);
#endif /* _LVM_DAEMON_SHARED_H */