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lightningd: tighten interal json_stream API.

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Move it closer to ccan/json_out, in preparation for using that as a
replacement.

In particular:

1. Add a 'quote' field in json_add_member.
2. json_add_member now always escapes if 'quote' is true.
3. json_member_direct is exposed to allow avoiding of escaping.
4. json_add_hex can use this, so no longer needs to be in json_stream.c.
5. We don't make JSON manually, but always use helpers.
6. We now flush the stream (wake reader) only when we close it, or mark
   command as pending.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2019-06-12 10:08:55 +09:30
parent adc4bf1817
commit 7f75043ab2
9 changed files with 157 additions and 172 deletions
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132
lightningd/json_stream.c
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@@ -1,7 +1,9 @@
#include <ccan/io/io.h>
/* To reach into io_plan: not a public header! */
#include <ccan/io/backend.h>
#include <ccan/json_escape/json_escape.h>
#include <ccan/str/hex/hex.h>
#include <ccan/tal/str/str.h>
#include <common/daemon.h>
#include <common/utils.h>
#include <lightningd/json.h>
@@ -94,15 +96,6 @@ bool json_stream_still_writing(const struct json_stream *js)
return js->writer != NULL;
}
void json_stream_close(struct json_stream *js, struct command *writer)
{
/* FIXME: We use writer == NULL for malformed: make writer a void *?
* I used to assert(writer); here. */
assert(js->writer == writer);
js->writer = NULL;
}
void json_stream_log_suppress(struct json_stream *js, const char *cmd_name)
{
/* Really shouldn't be used for anything else */
@@ -146,67 +139,30 @@ static char *mkroom(struct json_stream *js, size_t len)
return membuf_space(&js->outbuf);
}
/* Also called when we're oom, so it will kill reader. */
static void js_written_some(struct json_stream *js)
{
/* Wake the stream reader. FIXME: Could have a flag here to optimize */
io_wake(js);
}
void json_stream_append_part(struct json_stream *js, const char *str, size_t len)
void json_stream_append(struct json_stream *js,
const char *str, size_t len)
{
if (js->oom || !mkroom(js, len))
return;
memcpy(membuf_add(&js->outbuf, len), str, len);
js_written_some(js);
}
void json_stream_append(struct json_stream *js, const char *str)
void json_stream_close(struct json_stream *js, struct command *writer)
{
json_stream_append_part(js, str, strlen(str));
/* FIXME: We use writer == NULL for malformed: make writer a void *?
* I used to assert(writer); here. */
assert(js->writer == writer);
json_stream_append(js, "\n\n", strlen("\n\n"));
json_stream_flush(js);
js->writer = NULL;
}
static void json_stream_append_vfmt(struct json_stream *js,
const char *fmt, va_list ap)
/* Also called when we're oom, so it will kill reader. */
void json_stream_flush(struct json_stream *js)
{
size_t fmtlen;
va_list ap2;
if (js->oom)
return;
/* Make a copy in case we need it below. */
va_copy(ap2, ap);
/* Try printing in place first. */
fmtlen = vsnprintf(membuf_space(&js->outbuf),
membuf_num_space(&js->outbuf), fmt, ap);
/* Horrible subtlety: vsnprintf *will* NUL terminate, even if it means
* chopping off the last character. So if fmtlen ==
* membuf_num_space(&jcon->outbuf), the result was truncated! */
if (fmtlen >= membuf_num_space(&js->outbuf)) {
/* Make room for NUL terminator, even though we don't want it */
char *p = mkroom(js, fmtlen + 1);
if (!p)
goto oom;
vsprintf(p, fmt, ap2);
}
membuf_added(&js->outbuf, fmtlen);
oom:
js_written_some(js);
va_end(ap2);
}
void PRINTF_FMT(2,3)
json_stream_append_fmt(struct json_stream *js, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
json_stream_append_vfmt(js, fmt, ap);
va_end(ap);
/* Wake the stream reader. FIXME: Could have a flag here to optimize */
io_wake(js);
}
static void check_fieldname(const struct json_stream *js,
@@ -226,11 +182,8 @@ static void check_fieldname(const struct json_stream *js,
#endif
}
/* Caller must call js_written_some() if extra is non-zero returns non-NULL!
* Can return NULL, beware:
*/
static char *json_start_member(struct json_stream *js,
const char *fieldname, size_t extra)
char *json_member_direct(struct json_stream *js,
const char *fieldname, size_t extra)
{
char *dest;
@@ -291,61 +244,60 @@ static void js_unindent(struct json_stream *js, jsmntype_t type)
void json_array_start(struct json_stream *js, const char *fieldname)
{
char *dest = json_start_member(js, fieldname, 1);
char *dest = json_member_direct(js, fieldname, 1);
if (dest)
dest[0] = '[';
js_written_some(js);
js_indent(js, JSMN_ARRAY);
}
void json_array_end(struct json_stream *js)
{
js_unindent(js, JSMN_ARRAY);
json_stream_append(js, "]");
json_stream_append(js, "]", 1);
}
void json_object_start(struct json_stream *js, const char *fieldname)
{
char *dest = json_start_member(js, fieldname, 1);
char *dest = json_member_direct(js, fieldname, 1);
if (dest)
dest[0] = '{';
js_written_some(js);
js_indent(js, JSMN_OBJECT);
}
void json_object_end(struct json_stream *js)
{
js_unindent(js, JSMN_OBJECT);
json_stream_append(js, "}");
json_stream_append(js, "}", 1);
}
void PRINTF_FMT(3,4)
json_add_member(struct json_stream *js, const char *fieldname,
const char *fmt, ...)
void json_add_member(struct json_stream *js,
const char *fieldname,
bool quote,
const char *fmt, ...)
{
va_list ap;
char *str, *p;
json_start_member(js, fieldname, 0);
va_start(ap, fmt);
json_stream_append_vfmt(js, fmt, ap);
str = tal_vfmt(NULL, fmt, ap);
va_end(ap);
}
void json_add_hex(struct json_stream *js, const char *fieldname,
const void *data, size_t len)
{
/* Size without NUL term */
size_t hexlen = hex_str_size(len) - 1;
char *dest;
if (quote) {
struct json_escape *e = json_escape(NULL, take(str));
dest = json_start_member(js, fieldname, 1 + hexlen + 1);
if (dest) {
dest[0] = '"';
if (!hex_encode(data, len, dest + 1, hexlen + 1))
abort();
dest[1+hexlen] = '"';
p = json_member_direct(js, fieldname, strlen(e->s) + 2);
if (!p)
return;
p[0] = p[1 + strlen(e->s)] = '"';
memcpy(p+1, e->s, strlen(e->s));
tal_free(e);
} else {
p = json_member_direct(js, fieldname, strlen(str));
if (!p)
return;
memcpy(p, str, strlen(str));
tal_free(str);
}
js_written_some(js);
}
/* This is where we read the json_stream and write it to conn */