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json.c
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json.c
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/* Copyright 2012-present Facebook, Inc.
* Licensed under the Apache License, Version 2.0 */
#include "watchman.h"
bool w_json_buffer_init(w_jbuffer_t *jr)
{
memset(jr, 0, sizeof(*jr));
jr->allocd = 8192;
jr->buf = malloc(jr->allocd);
if (!jr->buf) {
return false;
}
return true;
}
void w_json_buffer_free(w_jbuffer_t *jr)
{
free(jr->buf);
memset(jr, 0, sizeof(*jr));
}
json_t *w_json_buffer_next(w_jbuffer_t *jr, int fd, json_error_t *jerr)
{
char *nl;
int r;
json_t *res;
/* look for a newline; that indicates the end of
* a json packet */
nl = memchr(jr->buf + jr->rpos, '\n', jr->wpos - jr->rpos);
// If we don't have a newline, we need to fill the
// buffer
while (!nl) {
uint32_t avail = jr->allocd - jr->wpos;
// Shunt down
if (jr->rpos && jr->rpos < jr->wpos) {
memmove(jr->buf, jr->buf + jr->rpos, jr->wpos - jr->rpos);
jr->wpos -= jr->rpos;
jr->rpos = 0;
avail = jr->allocd - jr->wpos;
}
// Get some more space if we need it
if (avail == 0) {
char *buf = realloc(jr->buf, jr->allocd * 2);
if (!buf) {
return NULL;
}
jr->buf = buf;
jr->allocd *= 2;
avail = jr->allocd - jr->wpos;
}
r = read(fd, jr->buf + jr->wpos, avail);
if (r <= 0) {
return NULL;
}
jr->wpos += r;
// Look for a newline in the data we just read
nl = memchr(jr->buf + jr->wpos - r, '\n', r);
}
// buflen
r = nl - (jr->buf + jr->rpos);
res = json_loadb(jr->buf + jr->rpos, r, 0, jerr);
// update read pos to look beyond this point
jr->rpos += r + 1;
return res;
}
struct jbuffer_write_data {
int fd;
w_jbuffer_t *jr;
};
static bool jbuffer_flush(struct jbuffer_write_data *data)
{
int x;
while (data->jr->wpos - data->jr->rpos) {
x = write(data->fd, data->jr->buf + data->jr->rpos,
data->jr->wpos - data->jr->rpos);
if (x <= 0) {
return false;
}
data->jr->rpos += x;
}
data->jr->rpos = data->jr->wpos = 0;
return true;
}
static int jbuffer_write(const char *buffer, size_t size, void *ptr)
{
struct jbuffer_write_data *data = ptr;
while (size) {
// Accumulate in the buffer
size_t room = data->jr->allocd - data->jr->wpos;
// No room? send it over the wire
if (!room) {
if (!jbuffer_flush(data)) {
return -1;
}
room = data->jr->allocd - data->jr->wpos;
}
if (size < room) {
room = size;
}
// Stick it in the buffer
memcpy(data->jr->buf + data->jr->wpos,
buffer, room);
buffer += room;
size -= room;
data->jr->wpos += room;
}
return 0;
}
bool w_json_buffer_write(w_jbuffer_t *jr, int fd, json_t *json, int flags)
{
struct jbuffer_write_data data = { fd, jr };
int res;
res = json_dump_callback(json, jbuffer_write, &data, flags);
if (res != 0) {
return false;
}
if (jbuffer_write("\n", 1, &data) != 0) {
return false;
}
return jbuffer_flush(&data);
}
/* vim:ts=2:sw=2:et:
*/