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7f75043ab2
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>
134 lines
4.0 KiB
C
134 lines
4.0 KiB
C
/* lightningd/json_stream.h
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* Helpers for outputting JSON results into a membuf.
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*/
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#ifndef LIGHTNING_LIGHTNINGD_JSON_STREAM_H
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#define LIGHTNING_LIGHTNINGD_JSON_STREAM_H
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#include "config.h"
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#include <ccan/membuf/membuf.h>
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#include <ccan/short_types/short_types.h>
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#include <ccan/tal/tal.h>
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#include <ccan/typesafe_cb/typesafe_cb.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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struct command;
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struct io_conn;
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struct json_stream;
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struct log;
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/**
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* new_json_stream - create a new JSON stream.
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* @ctx: tal context for allocation.
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* @writer: object responsible for writing to this stream.
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* @log: where to log the IO
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*/
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struct json_stream *new_json_stream(const tal_t *ctx, struct command *writer,
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struct log *log);
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/**
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* Duplicate an existing stream.
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*
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* Mostly useful when we want to send copies of a given stream to
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* multiple recipients, that might read at different speeds from the
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* stream. For example this is used when construcing a single
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* notification and then duplicating it for the fanout.
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*
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* @ctx: tal context for allocation.
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* @original: the stream to duplicate.
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* @log: log for new stream.
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*/
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struct json_stream *json_stream_dup(const tal_t *ctx,
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struct json_stream *original,
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struct log *log);
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/**
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* json_stream_close - finished writing to a JSON stream.
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* @js: the json_stream.
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* @writer: object responsible for writing to this stream.
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*/
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void json_stream_close(struct json_stream *js, struct command *writer);
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/* For low-level JSON stream access: */
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void json_stream_log_suppress(struct json_stream *js, const char *cmd_name);
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/**
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* json_stream_still_writing - is someone currently writing to this stream?
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* @js: the json_stream.
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*
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* Has this json_stream not been closed yet?
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*/
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bool json_stream_still_writing(const struct json_stream *js);
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/* '"fieldname" : [ ' or '[ ' if fieldname is NULL */
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void json_array_start(struct json_stream *js, const char *fieldname);
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/* '"fieldname" : { ' or '{ ' if fieldname is NULL */
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void json_object_start(struct json_stream *ks, const char *fieldname);
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/* ' ], ' */
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void json_array_end(struct json_stream *js);
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/* ' }, ' */
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void json_object_end(struct json_stream *js);
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/**
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* json_stream_append - literally insert this string into the json_stream.
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* @js: the json_stream.
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* @str: the string.
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* @len: the length to append (<= strlen(str)).
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*/
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void json_stream_append(struct json_stream *js, const char *str, size_t len);
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/**
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* json_add_member - add a generic member.
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* @js: the json_stream.
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* @fieldname: fieldname (if in object), otherwise must be NULL.
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* @quote: true if should be escaped and wrapped in "".
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* @fmt...: the printf-style format
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*
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* The resulting string from @fmt is escaped if quote is true:
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* see json_member_direct to avoid quoting.
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*/
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PRINTF_FMT(4,5)
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void json_add_member(struct json_stream *js,
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const char *fieldname,
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bool quote,
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const char *fmt, ...);
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/**
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* json_member_direct - start a generic member.
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* @js: the json_stream.
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* @fieldname: fieldname (if in object), otherwise must be NULL.
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* @extra: the space to reserve.
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*
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* Returns NULL if oom, otherwise returns a ptr to @extra bytes.
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*/
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char *json_member_direct(struct json_stream *js,
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const char *fieldname, size_t extra);
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/**
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* json_stream_output - start writing out a json_stream to this conn.
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* @js: the json_stream
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* @conn: the io_conn to write out to.
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* @cb: the callback to call once it's all written.
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* @arg: the argument to @cb
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*/
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#define json_stream_output(js, conn, cb, arg) \
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json_stream_output_((js), (conn), \
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typesafe_cb_preargs(struct io_plan *, \
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void *, \
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(cb), (arg), \
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struct io_conn *, \
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struct json_stream *), \
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(arg))
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struct io_plan *json_stream_output_(struct json_stream *js,
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struct io_conn *conn,
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struct io_plan *(*cb)(struct io_conn *conn,
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struct json_stream *js,
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void *arg),
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void *arg);
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void json_stream_flush(struct json_stream *js);
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#endif /* LIGHTNING_LIGHTNINGD_JSON_STREAM_H */
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