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connection: Factor out circular buffer functionality

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This commit is contained in:
Kristian Høgsberg 2010-08-26 17:44:31 -04:00
parent 4363d2aa4d
commit d6f4da7927
1 changed files with 113 additions and 106 deletions
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219
connection.c
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@ -43,6 +43,8 @@ struct wl_buffer {
int head, tail; int head, tail;
}; };
#define MASK(i) ((i) & 4095)
struct wl_connection { struct wl_connection {
struct wl_buffer in, out; struct wl_buffer in, out;
int fd; int fd;
@ -50,6 +52,86 @@ struct wl_connection {
wl_connection_update_func_t update; wl_connection_update_func_t update;
}; };
static void
wl_buffer_put(struct wl_buffer *b, const void *data, size_t count)
{
int head, size;
head = MASK(b->head);
if (head + count <= sizeof b->data) {
memcpy(b->data + head, data, count);
} else {
size = sizeof b->data - head;
memcpy(b->data + head, data, size);
memcpy(b->data, (const char *) data + size, count - size);
}
b->head += count;
}
static void
wl_buffer_put_iov(struct wl_buffer *b, struct iovec *iov, int *count)
{
int head, tail;
head = MASK(b->head);
tail = MASK(b->tail);
if (head < tail) {
iov[0].iov_base = b->data + head;
iov[0].iov_len = tail - head;
*count = 1;
} else if (tail == 0) {
iov[0].iov_base = b->data + head;
iov[0].iov_len = sizeof b->data - head;
*count = 1;
} else {
iov[0].iov_base = b->data + head;
iov[0].iov_len = sizeof b->data - head;
iov[1].iov_base = b->data;
iov[1].iov_len = tail;
*count = 2;
}
}
static void
wl_buffer_get_iov(struct wl_buffer *b, struct iovec *iov, int *count)
{
int head, tail;
head = MASK(b->head);
tail = MASK(b->tail);
if (tail < head) {
iov[0].iov_base = b->data + tail;
iov[0].iov_len = head - tail;
*count = 1;
} else if (head == 0) {
iov[0].iov_base = b->data + tail;
iov[0].iov_len = sizeof b->data - tail;
*count = 1;
} else {
iov[0].iov_base = b->data + tail;
iov[0].iov_len = sizeof b->data - tail;
iov[1].iov_base = b->data;
iov[1].iov_len = head;
*count = 2;
}
}
static void
wl_buffer_copy(struct wl_buffer *b, void *data, size_t count)
{
int tail, size;
tail = MASK(b->tail);
if (tail + count <= sizeof b->data) {
memcpy(data, b->data + tail, count);
} else {
size = sizeof b->data - tail;
memcpy(data, b->data + tail, size);
memcpy((char *) data + size, b->data, count - size);
}
}
struct wl_connection * struct wl_connection *
wl_connection_create(int fd, wl_connection_create(int fd,
wl_connection_update_func_t update, wl_connection_update_func_t update,
@ -80,67 +162,35 @@ wl_connection_destroy(struct wl_connection *connection)
void void
wl_connection_copy(struct wl_connection *connection, void *data, size_t size) wl_connection_copy(struct wl_connection *connection, void *data, size_t size)
{ {
struct wl_buffer *b; wl_buffer_copy(&connection->in, data, size);
int tail, rest;
b = &connection->in;
tail = b->tail;
if (tail + size <= ARRAY_LENGTH(b->data)) {
memcpy(data, b->data + tail, size);
} else {
rest = ARRAY_LENGTH(b->data) - tail;
memcpy(data, b->data + tail, rest);
memcpy(data + rest, b->data, size - rest);
}
} }
void void
wl_connection_consume(struct wl_connection *connection, size_t size) wl_connection_consume(struct wl_connection *connection, size_t size)
{ {
struct wl_buffer *b; connection->in.tail += size;
int tail, rest;
b = &connection->in;
tail = b->tail;
if (tail + size <= ARRAY_LENGTH(b->data)) {
b->tail += size;
} else {
rest = ARRAY_LENGTH(b->data) - tail;
b->tail = size - rest;
}
} }
int wl_connection_data(struct wl_connection *connection, uint32_t mask) int wl_connection_data(struct wl_connection *connection, uint32_t mask)
{ {
struct wl_buffer *b;
struct iovec iov[2]; struct iovec iov[2];
struct msghdr msg; struct msghdr msg;
int len, head, tail, count, size, available; int len, count;
if (mask & WL_CONNECTION_READABLE) { if (mask & WL_CONNECTION_READABLE) {
b = &connection->in; wl_buffer_put_iov(&connection->in, iov, &count);
head = connection->in.head;
if (head < b->tail) { msg.msg_name = NULL;
iov[0].iov_base = b->data + head; msg.msg_namelen = 0;
iov[0].iov_len = b->tail - head; msg.msg_iov = iov;
count = 1; msg.msg_iovlen = count;
} else { msg.msg_control = NULL;
size = ARRAY_LENGTH(b->data) - head; msg.msg_controllen = 0;
iov[0].iov_base = b->data + head;
iov[0].iov_len = size;
iov[1].iov_base = b->data;
iov[1].iov_len = b->tail;
count = 2;
}
do { do {
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = iov;
msg.msg_iovlen = count;
msg.msg_control = NULL;
msg.msg_controllen = 0;
len = recvmsg(connection->fd, &msg, 0); len = recvmsg(connection->fd, &msg, 0);
} while (len < 0 && errno == EINTR); } while (len < 0 && errno == EINTR);
if (len < 0) { if (len < 0) {
fprintf(stderr, fprintf(stderr,
"read error from connection %p: %m (%d)\n", "read error from connection %p: %m (%d)\n",
@ -149,90 +199,47 @@ int wl_connection_data(struct wl_connection *connection, uint32_t mask)
} else if (len == 0) { } else if (len == 0) {
/* FIXME: Handle this better? */ /* FIXME: Handle this better? */
return -1; return -1;
} else if (head + len <= ARRAY_LENGTH(b->data)) {
b->head += len;
} else {
b->head = head + len - ARRAY_LENGTH(b->data);
} }
/* We know we have data in the buffer at this point, connection->in.head += len;
* so if head equals tail, it means the buffer is
* full. */
available = b->head - b->tail;
if (available == 0)
available = sizeof b->data;
else if (available < 0)
available += ARRAY_LENGTH(b->data);
} else {
available = 0;
} }
if (mask & WL_CONNECTION_WRITABLE) { if (mask & WL_CONNECTION_WRITABLE) {
b = &connection->out; wl_buffer_get_iov(&connection->out, iov, &count);
tail = b->tail;
if (tail < b->head) { msg.msg_name = NULL;
iov[0].iov_base = b->data + tail; msg.msg_namelen = 0;
iov[0].iov_len = b->head - tail; msg.msg_iov = iov;
count = 1; msg.msg_iovlen = count;
} else { msg.msg_control = NULL;
size = ARRAY_LENGTH(b->data) - tail; msg.msg_controllen = 0;
iov[0].iov_base = b->data + tail;
iov[0].iov_len = size;
iov[1].iov_base = b->data;
iov[1].iov_len = b->head;
count = 2;
}
do { do {
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = iov;
msg.msg_iovlen = count;
msg.msg_control = NULL;
msg.msg_controllen = 0;
len = sendmsg(connection->fd, &msg, 0); len = sendmsg(connection->fd, &msg, 0);
} while (len < 0 && errno == EINTR); } while (len < 0 && errno == EINTR);
if (len < 0) { if (len < 0) {
fprintf(stderr, "write error for connection %p: %m\n", connection); fprintf(stderr, "write error for connection %p: %m\n", connection);
return -1; return -1;
} else if (tail + len <= ARRAY_LENGTH(b->data)) {
b->tail += len;
} else {
b->tail = tail + len - ARRAY_LENGTH(b->data);
} }
/* We just took data out of the buffer, so at this connection->out.tail += len;
* point if head equals tail, the buffer is empty. */ if (connection->out.tail == connection->out.head)
if (b->tail == b->head)
connection->update(connection, connection->update(connection,
WL_CONNECTION_READABLE, WL_CONNECTION_READABLE,
connection->data); connection->data);
} }
return available; return connection->in.head - connection->in.tail;
} }
void void
wl_connection_write(struct wl_connection *connection, const void *data, size_t count) wl_connection_write(struct wl_connection *connection,
const void *data, size_t count)
{ {
struct wl_buffer *b; wl_buffer_put(&connection->out, data, count);
size_t size;
int head;
b = &connection->out; if (connection->out.head - connection->out.tail == count)
head = b->head;
if (head + count <= ARRAY_LENGTH(b->data)) {
memcpy(b->data + head, data, count);
b->head += count;
} else {
size = ARRAY_LENGTH(b->data) - head;
memcpy(b->data + head, data, size);
memcpy(b->data, data + size, count - size);
b->head = count - size;
}
if (b->tail == head)
connection->update(connection, connection->update(connection,
WL_CONNECTION_READABLE | WL_CONNECTION_READABLE |
WL_CONNECTION_WRITABLE, WL_CONNECTION_WRITABLE,