Browse Source
We promote 'struct json_stream' to contain the membuf; we only attach the json_stream to the command when we actually call json_stream_success / json_stream_fail. This means we are closer to 'struct json_stream' being an independent layer; the tests are already modified to use it directly to create JSON. This is also the first step toward re-enabling non-serial command execution. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>trytravis
Rusty Russell
6 years ago
committed by
Christian Decker
Christian Decker
12 changed files with 499 additions and 356 deletions
@ -0,0 +1,289 @@ |
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#include <ccan/io/io.h> |
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/* To reach into io_plan: not a public header! */ |
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#include <ccan/io/backend.h> |
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#include <common/utils.h> |
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#include <lightningd/json.h> |
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#include <lightningd/json_stream.h> |
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#include <stdarg.h> |
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#include <stdio.h> |
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struct json_stream { |
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#if DEVELOPER |
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/* tal_arr of types (JSMN_OBJECT/JSMN_ARRAY) we're enclosed in. */ |
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jsmntype_t *wrapping; |
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#endif |
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/* How far to indent. */ |
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size_t indent; |
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/* True if we haven't yet put an element in current wrapping */ |
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bool empty; |
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/* Who is writing to this buffer now; NULL if nobody is. */ |
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struct command *writer; |
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/* Who is io_writing from this buffer now: NULL if nobody is. */ |
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struct io_conn *reader; |
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struct io_plan *(*reader_cb)(struct io_conn *conn, void *arg); |
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void *reader_arg; |
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size_t len_read; |
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/* Current command's output. */ |
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MEMBUF(char) outbuf; |
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}; |
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/* Realloc helper for tal membufs */ |
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static void *membuf_tal_realloc(struct membuf *mb, |
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void *rawelems, size_t newsize) |
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{ |
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char *p = rawelems; |
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tal_resize(&p, newsize); |
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return p; |
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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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{ |
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struct json_stream *js = tal(ctx, struct json_stream); |
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js->writer = writer; |
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js->reader = NULL; |
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membuf_init(&js->outbuf, |
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tal_arr(js, char, 64), 64, membuf_tal_realloc); |
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#if DEVELOPER |
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js->wrapping = tal_arr(js, jsmntype_t, 0); |
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#endif |
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js->indent = 0; |
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js->empty = true; |
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return js; |
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} |
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bool json_stream_still_writing(const struct json_stream *js) |
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{ |
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return js->writer != NULL; |
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} |
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void json_stream_close(struct json_stream *js, struct command *writer) |
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{ |
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/* FIXME: We use writer == NULL for malformed: make writer a void *?
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* I used to assert(writer); here. */ |
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assert(js->writer == writer); |
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js->writer = NULL; |
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} |
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/* FIXME: This, or something prettier (io_replan?) belong in ccan/io! */ |
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static void adjust_io_write(struct io_conn *conn, ptrdiff_t delta) |
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{ |
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conn->plan[IO_OUT].arg.u1.cp += delta; |
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} |
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/* Make sure js->outbuf has room for len */ |
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static void mkroom(struct json_stream *js, size_t len) |
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{ |
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ptrdiff_t delta = membuf_prepare_space(&js->outbuf, len); |
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/* If io_write is in progress, we shift it to point to new buffer pos */ |
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if (js->reader) |
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adjust_io_write(js->reader, delta); |
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} |
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static void js_written_some(struct json_stream *js) |
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{ |
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/* Wake the stream reader. FIXME: Could have a flag here to optimize */ |
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io_wake(js); |
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} |
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void json_stream_append(struct json_stream *js, const char *str) |
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{ |
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size_t len = strlen(str); |
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mkroom(js, len); |
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memcpy(membuf_add(&js->outbuf, len), str, len); |
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js_written_some(js); |
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} |
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static void json_stream_append_vfmt(struct json_stream *js, |
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const char *fmt, va_list ap) |
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{ |
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size_t fmtlen; |
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va_list ap2; |
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/* Make a copy in case we need it below. */ |
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va_copy(ap2, ap); |
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/* Try printing in place first. */ |
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fmtlen = vsnprintf(membuf_space(&js->outbuf), |
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membuf_num_space(&js->outbuf), fmt, ap); |
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/* Horrible subtlety: vsnprintf *will* NUL terminate, even if it means
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* chopping off the last character. So if fmtlen == |
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* membuf_num_space(&jcon->outbuf), the result was truncated! */ |
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if (fmtlen >= membuf_num_space(&js->outbuf)) { |
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/* Make room for NUL terminator, even though we don't want it */ |
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mkroom(js, fmtlen + 1); |
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vsprintf(membuf_space(&js->outbuf), fmt, ap2); |
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} |
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membuf_added(&js->outbuf, fmtlen); |
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js_written_some(js); |
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va_end(ap2); |
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} |
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void PRINTF_FMT(2,3) |
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json_stream_append_fmt(struct json_stream *js, const char *fmt, ...) |
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{ |
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va_list ap; |
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va_start(ap, fmt); |
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json_stream_append_vfmt(js, fmt, ap); |
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va_end(ap); |
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} |
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static void check_fieldname(const struct json_stream *js, |
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const char *fieldname) |
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{ |
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#if DEVELOPER |
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size_t n = tal_count(js->wrapping); |
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if (n == 0) |
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/* Can't have a fieldname if not in anything! */ |
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assert(!fieldname); |
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else if (js->wrapping[n-1] == JSMN_ARRAY) |
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/* No fieldnames in arrays. */ |
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assert(!fieldname); |
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else |
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/* Must have fieldnames in objects. */ |
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assert(fieldname); |
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#endif |
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} |
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static void js_append_indent(struct json_stream *js) |
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{ |
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static const char indent_buf[] = " "; |
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size_t len; |
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for (size_t i = 0; i < js->indent * 2; i += len) { |
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len = js->indent * 2; |
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if (len > sizeof(indent_buf)-1) |
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len = sizeof(indent_buf)-1; |
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/* Use tail of indent_buf string. */ |
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json_stream_append(js, indent_buf + sizeof(indent_buf) - 1 - len); |
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} |
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} |
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static void json_start_member(struct json_stream *js, const char *fieldname) |
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{ |
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/* Prepend comma if required. */ |
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if (!js->empty) |
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json_stream_append(js, ", \n"); |
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else |
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json_stream_append(js, "\n"); |
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js_append_indent(js); |
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check_fieldname(js, fieldname); |
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if (fieldname) |
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json_stream_append_fmt(js, "\"%s\": ", fieldname); |
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js->empty = false; |
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} |
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static void js_indent(struct json_stream *js, jsmntype_t type) |
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{ |
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#if DEVELOPER |
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*tal_arr_expand(&js->wrapping) = type; |
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#endif |
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js->empty = true; |
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js->indent++; |
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} |
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static void js_unindent(struct json_stream *js, jsmntype_t type) |
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{ |
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assert(js->indent); |
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#if DEVELOPER |
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assert(tal_count(js->wrapping) == js->indent); |
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assert(js->wrapping[js->indent-1] == type); |
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tal_resize(&js->wrapping, js->indent-1); |
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#endif |
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js->empty = false; |
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js->indent--; |
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} |
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void json_array_start(struct json_stream *js, const char *fieldname) |
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{ |
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json_start_member(js, fieldname); |
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json_stream_append(js, "["); |
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js_indent(js, JSMN_ARRAY); |
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} |
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void json_array_end(struct json_stream *js) |
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{ |
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json_stream_append(js, "\n"); |
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js_unindent(js, JSMN_ARRAY); |
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js_append_indent(js); |
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json_stream_append(js, "]"); |
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} |
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void json_object_start(struct json_stream *js, const char *fieldname) |
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{ |
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json_start_member(js, fieldname); |
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json_stream_append(js, "{"); |
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js_indent(js, JSMN_OBJECT); |
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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(js, "\n"); |
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js_unindent(js, JSMN_OBJECT); |
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js_append_indent(js); |
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json_stream_append(js, "}"); |
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} |
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void PRINTF_FMT(3,4) |
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json_add_member(struct json_stream *js, const char *fieldname, |
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const char *fmt, ...) |
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{ |
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va_list ap; |
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json_start_member(js, fieldname); |
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va_start(ap, fmt); |
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json_stream_append_vfmt(js, fmt, ap); |
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va_end(ap); |
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} |
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/* This is where we read the json_stream and write it to conn */ |
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static struct io_plan *json_stream_output_write(struct io_conn *conn, |
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struct json_stream *js) |
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{ |
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/* For when we've just done some output */ |
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membuf_consume(&js->outbuf, js->len_read); |
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/* Get how much we can write out from js */ |
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js->len_read = membuf_num_elems(&js->outbuf); |
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/* Nothing in buffer? */ |
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if (js->len_read == 0) { |
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/* We're not doing io_write now, unset. */ |
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js->reader = NULL; |
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if (!json_stream_still_writing(js)) |
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return js->reader_cb(conn, js->reader_arg); |
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return io_out_wait(conn, js, json_stream_output_write, js); |
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} |
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js->reader = conn; |
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return io_write(conn, |
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membuf_elems(&js->outbuf), js->len_read, |
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json_stream_output_write, js); |
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} |
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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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void *arg), |
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void *arg) |
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{ |
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assert(!js->reader); |
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js->reader_cb = cb; |
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js->reader_arg = arg; |
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js->len_read = 0; |
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return json_stream_output_write(conn, js); |
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} |
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@ -0,0 +1,97 @@ |
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/* 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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/**
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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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*/ |
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struct json_stream *new_json_stream(const tal_t *ctx, struct command *writer); |
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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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/**
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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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*/ |
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void json_stream_append(struct json_stream *js, const char *str); |
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/**
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* json_stream_append_fmt - insert formatted string into the json_stream. |
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* @js: the json_stream. |
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* @fmt...: the printf-style format |
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*/ |
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void PRINTF_FMT(2,3) |
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json_stream_append_fmt(struct json_stream *js, const char *fmt, ...); |
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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: optional fieldname. |
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* @fmt...: the printf-style format |
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*/ |
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void PRINTF_FMT(3,4) |
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json_add_member(struct json_stream *js, const char *fieldname, |
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const char *fmt, ...); |
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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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(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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void *arg), |
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void *arg); |
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#endif /* LIGHTNING_LIGHTNINGD_JSON_STREAM_H */ |
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