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protobuf/upb/json/parser.c

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#line 1 "upb/json/parser.rl"
/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2014 Google Inc. See LICENSE for details.
* Author: Josh Haberman <jhaberman@gmail.com>
*
* A parser that uses the Ragel State Machine Compiler to generate
* the finite automata.
*
* Ragel only natively handles regular languages, but we can manually
* program it a bit to handle context-free languages like JSON, by using
* the "fcall" and "fret" constructs.
*
* This parser can handle the basics, but needs several things to be fleshed
* out:
*
* - handling of unicode escape sequences (including high surrogate pairs).
* - properly check and report errors for unknown fields, stack overflow,
* improper array nesting (or lack of nesting).
* - handling of base64 sequences with padding characters.
* - handling of push-back (non-success returns from sink functions).
* - handling of keys/escape-sequences/etc that span input buffers.
*/
#include <stdio.h>
#include <stdint.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "upb/json/parser.h"
#define UPB_JSON_MAX_DEPTH 64
typedef struct {
upb_sink sink;
// The current message in which we're parsing, and the field whose value we're
// expecting next.
const upb_msgdef *m;
const upb_fielddef *f;
// We are in a repeated-field context, ready to emit mapentries as
// submessages. This flag alters the start-of-object (open-brace) behavior to
// begin a sequence of mapentry messages rather than a single submessage.
bool is_map;
// We are in a map-entry message context. This flag is set when parsing the
// value field of a single map entry and indicates to all value-field parsers
// (subobjects, strings, numbers, and bools) that the map-entry submessage
// should end as soon as the value is parsed.
bool is_mapentry;
// If |is_map| or |is_mapentry| is true, |mapfield| refers to the parent
// message's map field that we're currently parsing. This differs from |f|
// because |f| is the field in the *current* message (i.e., the map-entry
// message itself), not the parent's field that leads to this map.
const upb_fielddef *mapfield;
} upb_jsonparser_frame;
struct upb_json_parser {
upb_env *env;
upb_byteshandler input_handler_;
upb_bytessink input_;
// Stack to track the JSON scopes we are in.
upb_jsonparser_frame stack[UPB_JSON_MAX_DEPTH];
upb_jsonparser_frame *top;
upb_jsonparser_frame *limit;
upb_status *status;
// Ragel's internal parsing stack for the parsing state machine.
int current_state;
int parser_stack[UPB_JSON_MAX_DEPTH];
int parser_top;
// The handle for the current buffer.
const upb_bufhandle *handle;
// Accumulate buffer. See details in parser.rl.
const char *accumulated;
size_t accumulated_len;
char *accumulate_buf;
size_t accumulate_buf_size;
// Multi-part text data. See details in parser.rl.
int multipart_state;
upb_selector_t string_selector;
// Input capture. See details in parser.rl.
const char *capture;
// Intermediate result of parsing a unicode escape sequence.
uint32_t digit;
};
#define PARSER_CHECK_RETURN(x) if (!(x)) return false
// Used to signal that a capture has been suspended.
static char suspend_capture;
static upb_selector_t getsel_for_handlertype(upb_json_parser *p,
upb_handlertype_t type) {
upb_selector_t sel;
bool ok = upb_handlers_getselector(p->top->f, type, &sel);
UPB_ASSERT_VAR(ok, ok);
return sel;
}
static upb_selector_t parser_getsel(upb_json_parser *p) {
return getsel_for_handlertype(
p, upb_handlers_getprimitivehandlertype(p->top->f));
}
static bool check_stack(upb_json_parser *p) {
if ((p->top + 1) == p->limit) {
upb_status_seterrmsg(p->status, "Nesting too deep");
return false;
}
return true;
}
// There are GCC/Clang built-ins for overflow checking which we could start
// using if there was any performance benefit to it.
static bool checked_add(size_t a, size_t b, size_t *c) {
if (SIZE_MAX - a < b) return false;
*c = a + b;
return true;
}
static size_t saturating_multiply(size_t a, size_t b) {
// size_t is unsigned, so this is defined behavior even on overflow.
size_t ret = a * b;
if (b != 0 && ret / b != a) {
ret = SIZE_MAX;
}
return ret;
}
/* Base64 decoding ************************************************************/
// TODO(haberman): make this streaming.
static const signed char b64table[] = {
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, 62/*+*/, -1, -1, -1, 63/*/ */,
52/*0*/, 53/*1*/, 54/*2*/, 55/*3*/, 56/*4*/, 57/*5*/, 58/*6*/, 59/*7*/,
60/*8*/, 61/*9*/, -1, -1, -1, -1, -1, -1,
-1, 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/,
07/*H*/, 8/*I*/, 9/*J*/, 10/*K*/, 11/*L*/, 12/*M*/, 13/*N*/, 14/*O*/,
15/*P*/, 16/*Q*/, 17/*R*/, 18/*S*/, 19/*T*/, 20/*U*/, 21/*V*/, 22/*W*/,
23/*X*/, 24/*Y*/, 25/*Z*/, -1, -1, -1, -1, -1,
-1, 26/*a*/, 27/*b*/, 28/*c*/, 29/*d*/, 30/*e*/, 31/*f*/, 32/*g*/,
33/*h*/, 34/*i*/, 35/*j*/, 36/*k*/, 37/*l*/, 38/*m*/, 39/*n*/, 40/*o*/,
41/*p*/, 42/*q*/, 43/*r*/, 44/*s*/, 45/*t*/, 46/*u*/, 47/*v*/, 48/*w*/,
49/*x*/, 50/*y*/, 51/*z*/, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1
};
// Returns the table value sign-extended to 32 bits. Knowing that the upper
// bits will be 1 for unrecognized characters makes it easier to check for
// this error condition later (see below).
int32_t b64lookup(unsigned char ch) { return b64table[ch]; }
// Returns true if the given character is not a valid base64 character or
// padding.
bool nonbase64(unsigned char ch) { return b64lookup(ch) == -1 && ch != '='; }
static bool base64_push(upb_json_parser *p, upb_selector_t sel, const char *ptr,
size_t len) {
const char *limit = ptr + len;
for (; ptr < limit; ptr += 4) {
if (limit - ptr < 4) {
upb_status_seterrf(p->status,
"Base64 input for bytes field not a multiple of 4: %s",
upb_fielddef_name(p->top->f));
return false;
}
uint32_t val = b64lookup(ptr[0]) << 18 |
b64lookup(ptr[1]) << 12 |
b64lookup(ptr[2]) << 6 |
b64lookup(ptr[3]);
// Test the upper bit; returns true if any of the characters returned -1.
if (val & 0x80000000) {
goto otherchar;
}
char output[3];
output[0] = val >> 16;
output[1] = (val >> 8) & 0xff;
output[2] = val & 0xff;
upb_sink_putstring(&p->top->sink, sel, output, 3, NULL);
}
return true;
otherchar:
if (nonbase64(ptr[0]) || nonbase64(ptr[1]) || nonbase64(ptr[2]) ||
nonbase64(ptr[3]) ) {
upb_status_seterrf(p->status,
"Non-base64 characters in bytes field: %s",
upb_fielddef_name(p->top->f));
return false;
} if (ptr[2] == '=') {
// Last group contains only two input bytes, one output byte.
if (ptr[0] == '=' || ptr[1] == '=' || ptr[3] != '=') {
goto badpadding;
}
uint32_t val = b64lookup(ptr[0]) << 18 |
b64lookup(ptr[1]) << 12;
assert(!(val & 0x80000000));
char output = val >> 16;
upb_sink_putstring(&p->top->sink, sel, &output, 1, NULL);
return true;
} else {
// Last group contains only three input bytes, two output bytes.
if (ptr[0] == '=' || ptr[1] == '=' || ptr[2] == '=') {
goto badpadding;
}
uint32_t val = b64lookup(ptr[0]) << 18 |
b64lookup(ptr[1]) << 12 |
b64lookup(ptr[2]) << 6;
char output[2];
output[0] = val >> 16;
output[1] = (val >> 8) & 0xff;
upb_sink_putstring(&p->top->sink, sel, output, 2, NULL);
return true;
}
badpadding:
upb_status_seterrf(p->status,
"Incorrect base64 padding for field: %s (%.*s)",
upb_fielddef_name(p->top->f),
4, ptr);
return false;
}
/* Accumulate buffer **********************************************************/
// Functionality for accumulating a buffer.
//
// Some parts of the parser need an entire value as a contiguous string. For
// example, to look up a member name in a hash table, or to turn a string into
// a number, the relevant library routines need the input string to be in
// contiguous memory, even if the value spanned two or more buffers in the
// input. These routines handle that.
//
// In the common case we can just point to the input buffer to get this
// contiguous string and avoid any actual copy. So we optimistically begin
// this way. But there are a few cases where we must instead copy into a
// separate buffer:
//
// 1. The string was not contiguous in the input (it spanned buffers).
//
// 2. The string included escape sequences that need to be interpreted to get
// the true value in a contiguous buffer.
static void assert_accumulate_empty(upb_json_parser *p) {
UPB_UNUSED(p);
assert(p->accumulated == NULL);
assert(p->accumulated_len == 0);
}
static void accumulate_clear(upb_json_parser *p) {
p->accumulated = NULL;
p->accumulated_len = 0;
}
// Used internally by accumulate_append().
static bool accumulate_realloc(upb_json_parser *p, size_t need) {
size_t old_size = p->accumulate_buf_size;
size_t new_size = UPB_MAX(old_size, 128);
while (new_size < need) {
new_size = saturating_multiply(new_size, 2);
}
void *mem = upb_env_realloc(p->env, p->accumulate_buf, old_size, new_size);
if (!mem) {
upb_status_seterrmsg(p->status, "Out of memory allocating buffer.");
return false;
}
p->accumulate_buf = mem;
p->accumulate_buf_size = new_size;
return true;
}
// Logically appends the given data to the append buffer.
// If "can_alias" is true, we will try to avoid actually copying, but the buffer
// must be valid until the next accumulate_append() call (if any).
static bool accumulate_append(upb_json_parser *p, const char *buf, size_t len,
bool can_alias) {
if (!p->accumulated && can_alias) {
p->accumulated = buf;
p->accumulated_len = len;
return true;
}
size_t need;
if (!checked_add(p->accumulated_len, len, &need)) {
upb_status_seterrmsg(p->status, "Integer overflow.");
return false;
}
if (need > p->accumulate_buf_size && !accumulate_realloc(p, need)) {
return false;
}
if (p->accumulated != p->accumulate_buf) {
memcpy(p->accumulate_buf, p->accumulated, p->accumulated_len);
p->accumulated = p->accumulate_buf;
}
memcpy(p->accumulate_buf + p->accumulated_len, buf, len);
p->accumulated_len += len;
return true;
}
// Returns a pointer to the data accumulated since the last accumulate_clear()
// call, and writes the length to *len. This with point either to the input
// buffer or a temporary accumulate buffer.
static const char *accumulate_getptr(upb_json_parser *p, size_t *len) {
assert(p->accumulated);
*len = p->accumulated_len;
return p->accumulated;
}
/* Mult-part text data ********************************************************/
// When we have text data in the input, it can often come in multiple segments.
// For example, there may be some raw string data followed by an escape
// sequence. The two segments are processed with different logic. Also buffer
// seams in the input can cause multiple segments.
//
// As we see segments, there are two main cases for how we want to process them:
//
// 1. we want to push the captured input directly to string handlers.
//
// 2. we need to accumulate all the parts into a contiguous buffer for further
// processing (field name lookup, string->number conversion, etc).
// This is the set of states for p->multipart_state.
enum {
// We are not currently processing multipart data.
MULTIPART_INACTIVE = 0,
// We are processing multipart data by accumulating it into a contiguous
// buffer.
MULTIPART_ACCUMULATE = 1,
// We are processing multipart data by pushing each part directly to the
// current string handlers.
MULTIPART_PUSHEAGERLY = 2
};
// Start a multi-part text value where we accumulate the data for processing at
// the end.
static void multipart_startaccum(upb_json_parser *p) {
assert_accumulate_empty(p);
assert(p->multipart_state == MULTIPART_INACTIVE);
p->multipart_state = MULTIPART_ACCUMULATE;
}
// Start a multi-part text value where we immediately push text data to a string
// value with the given selector.
static void multipart_start(upb_json_parser *p, upb_selector_t sel) {
assert_accumulate_empty(p);
assert(p->multipart_state == MULTIPART_INACTIVE);
p->multipart_state = MULTIPART_PUSHEAGERLY;
p->string_selector = sel;
}
static bool multipart_text(upb_json_parser *p, const char *buf, size_t len,
bool can_alias) {
switch (p->multipart_state) {
case MULTIPART_INACTIVE:
upb_status_seterrmsg(
p->status, "Internal error: unexpected state MULTIPART_INACTIVE");
return false;
case MULTIPART_ACCUMULATE:
if (!accumulate_append(p, buf, len, can_alias)) {
return false;
}
break;
case MULTIPART_PUSHEAGERLY: {
const upb_bufhandle *handle = can_alias ? p->handle : NULL;
upb_sink_putstring(&p->top->sink, p->string_selector, buf, len, handle);
break;
}
}
return true;
}
// Note: this invalidates the accumulate buffer! Call only after reading its
// contents.
static void multipart_end(upb_json_parser *p) {
assert(p->multipart_state != MULTIPART_INACTIVE);
p->multipart_state = MULTIPART_INACTIVE;
accumulate_clear(p);
}
/* Input capture **************************************************************/
// Functionality for capturing a region of the input as text. Gracefully
// handles the case where a buffer seam occurs in the middle of the captured
// region.
static void capture_begin(upb_json_parser *p, const char *ptr) {
assert(p->multipart_state != MULTIPART_INACTIVE);
assert(p->capture == NULL);
p->capture = ptr;
}
static bool capture_end(upb_json_parser *p, const char *ptr) {
assert(p->capture);
if (multipart_text(p, p->capture, ptr - p->capture, true)) {
p->capture = NULL;
return true;
} else {
return false;
}
}
// This is called at the end of each input buffer (ie. when we have hit a
// buffer seam). If we are in the middle of capturing the input, this
// processes the unprocessed capture region.
static void capture_suspend(upb_json_parser *p, const char **ptr) {
if (!p->capture) return;
if (multipart_text(p, p->capture, *ptr - p->capture, false)) {
// We use this as a signal that we were in the middle of capturing, and
// that capturing should resume at the beginning of the next buffer.
//
// We can't use *ptr here, because we have no guarantee that this pointer
// will be valid when we resume (if the underlying memory is freed, then
// using the pointer at all, even to compare to NULL, is likely undefined
// behavior).
p->capture = &suspend_capture;
} else {
// Need to back up the pointer to the beginning of the capture, since
// we were not able to actually preserve it.
*ptr = p->capture;
}
}
static void capture_resume(upb_json_parser *p, const char *ptr) {
if (p->capture) {
assert(p->capture == &suspend_capture);
p->capture = ptr;
}
}
/* Callbacks from the parser **************************************************/
// These are the functions called directly from the parser itself.
// We define these in the same order as their declarations in the parser.
static char escape_char(char in) {
switch (in) {
case 'r': return '\r';
case 't': return '\t';
case 'n': return '\n';
case 'f': return '\f';
case 'b': return '\b';
case '/': return '/';
case '"': return '"';
case '\\': return '\\';
default:
assert(0);
return 'x';
}
}
static bool escape(upb_json_parser *p, const char *ptr) {
char ch = escape_char(*ptr);
return multipart_text(p, &ch, 1, false);
}
static void start_hex(upb_json_parser *p) {
p->digit = 0;
}
static void hexdigit(upb_json_parser *p, const char *ptr) {
char ch = *ptr;
p->digit <<= 4;
if (ch >= '0' && ch <= '9') {
p->digit += (ch - '0');
} else if (ch >= 'a' && ch <= 'f') {
p->digit += ((ch - 'a') + 10);
} else {
assert(ch >= 'A' && ch <= 'F');
p->digit += ((ch - 'A') + 10);
}
}
static bool end_hex(upb_json_parser *p) {
uint32_t codepoint = p->digit;
// emit the codepoint as UTF-8.
char utf8[3]; // support \u0000 -- \uFFFF -- need only three bytes.
int length = 0;
if (codepoint <= 0x7F) {
utf8[0] = codepoint;
length = 1;
} else if (codepoint <= 0x07FF) {
utf8[1] = (codepoint & 0x3F) | 0x80;
codepoint >>= 6;
utf8[0] = (codepoint & 0x1F) | 0xC0;
length = 2;
} else /* codepoint <= 0xFFFF */ {
utf8[2] = (codepoint & 0x3F) | 0x80;
codepoint >>= 6;
utf8[1] = (codepoint & 0x3F) | 0x80;
codepoint >>= 6;
utf8[0] = (codepoint & 0x0F) | 0xE0;
length = 3;
}
// TODO(haberman): Handle high surrogates: if codepoint is a high surrogate
// we have to wait for the next escape to get the full code point).
return multipart_text(p, utf8, length, false);
}
static void start_text(upb_json_parser *p, const char *ptr) {
capture_begin(p, ptr);
}
static bool end_text(upb_json_parser *p, const char *ptr) {
return capture_end(p, ptr);
}
static void start_number(upb_json_parser *p, const char *ptr) {
multipart_startaccum(p);
capture_begin(p, ptr);
}
static bool parse_number(upb_json_parser *p);
static bool end_number(upb_json_parser *p, const char *ptr) {
if (!capture_end(p, ptr)) {
return false;
}
return parse_number(p);
}
static bool parse_number(upb_json_parser *p) {
// strtol() and friends unfortunately do not support specifying the length of
// the input string, so we need to force a copy into a NULL-terminated buffer.
if (!multipart_text(p, "\0", 1, false)) {
return false;
}
size_t len;
const char *buf = accumulate_getptr(p, &len);
const char *myend = buf + len - 1; // One for NULL.
char *end;
switch (upb_fielddef_type(p->top->f)) {
case UPB_TYPE_ENUM:
case UPB_TYPE_INT32: {
long val = strtol(p->accumulated, &end, 0);
if (val > INT32_MAX || val < INT32_MIN || errno == ERANGE || end != myend)
goto err;
else
upb_sink_putint32(&p->top->sink, parser_getsel(p), val);
break;
}
case UPB_TYPE_INT64: {
long long val = strtoll(p->accumulated, &end, 0);
if (val > INT64_MAX || val < INT64_MIN || errno == ERANGE || end != myend)
goto err;
else
upb_sink_putint64(&p->top->sink, parser_getsel(p), val);
break;
}
case UPB_TYPE_UINT32: {
unsigned long val = strtoul(p->accumulated, &end, 0);
if (val > UINT32_MAX || errno == ERANGE || end != myend)
goto err;
else
upb_sink_putuint32(&p->top->sink, parser_getsel(p), val);
break;
}
case UPB_TYPE_UINT64: {
unsigned long long val = strtoull(p->accumulated, &end, 0);
if (val > UINT64_MAX || errno == ERANGE || end != myend)
goto err;
else
upb_sink_putuint64(&p->top->sink, parser_getsel(p), val);
break;
}
case UPB_TYPE_DOUBLE: {
double val = strtod(p->accumulated, &end);
if (errno == ERANGE || end != myend)
goto err;
else
upb_sink_putdouble(&p->top->sink, parser_getsel(p), val);
break;
}
case UPB_TYPE_FLOAT: {
float val = strtof(p->accumulated, &end);
if (errno == ERANGE || end != myend)
goto err;
else
upb_sink_putfloat(&p->top->sink, parser_getsel(p), val);
break;
}
default:
assert(false);
}
multipart_end(p);
return true;
err:
upb_status_seterrf(p->status, "error parsing number: %s", buf);
multipart_end(p);
return false;
}
static bool parser_putbool(upb_json_parser *p, bool val) {
if (upb_fielddef_type(p->top->f) != UPB_TYPE_BOOL) {
upb_status_seterrf(p->status,
"Boolean value specified for non-bool field: %s",
upb_fielddef_name(p->top->f));
return false;
}
bool ok = upb_sink_putbool(&p->top->sink, parser_getsel(p), val);
UPB_ASSERT_VAR(ok, ok);
return true;
}
static bool start_stringval(upb_json_parser *p) {
assert(p->top->f);
if (upb_fielddef_isstring(p->top->f)) {
if (!check_stack(p)) return false;
// Start a new parser frame: parser frames correspond one-to-one with
// handler frames, and string events occur in a sub-frame.
upb_jsonparser_frame *inner = p->top + 1;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
upb_sink_startstr(&p->top->sink, sel, 0, &inner->sink);
inner->m = p->top->m;
inner->f = p->top->f;
inner->is_map = false;
inner->is_mapentry = false;
p->top = inner;
if (upb_fielddef_type(p->top->f) == UPB_TYPE_STRING) {
// For STRING fields we push data directly to the handlers as it is
// parsed. We don't do this yet for BYTES fields, because our base64
// decoder is not streaming.
//
// TODO(haberman): make base64 decoding streaming also.
multipart_start(p, getsel_for_handlertype(p, UPB_HANDLER_STRING));
return true;
} else {
multipart_startaccum(p);
return true;
}
} else if (upb_fielddef_type(p->top->f) == UPB_TYPE_ENUM) {
// No need to push a frame -- symbolic enum names in quotes remain in the
// current parser frame.
//
// Enum string values must accumulate so we can look up the value in a table
// once it is complete.
multipart_startaccum(p);
return true;
} else {
upb_status_seterrf(p->status,
"String specified for non-string/non-enum field: %s",
upb_fielddef_name(p->top->f));
return false;
}
}
static bool end_stringval(upb_json_parser *p) {
bool ok = true;
switch (upb_fielddef_type(p->top->f)) {
case UPB_TYPE_BYTES:
if (!base64_push(p, getsel_for_handlertype(p, UPB_HANDLER_STRING),
p->accumulated, p->accumulated_len)) {
return false;
}
// Fall through.
case UPB_TYPE_STRING: {
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
upb_sink_endstr(&p->top->sink, sel);
p->top--;
break;
}
case UPB_TYPE_ENUM: {
// Resolve enum symbolic name to integer value.
const upb_enumdef *enumdef =
(const upb_enumdef*)upb_fielddef_subdef(p->top->f);
size_t len;
const char *buf = accumulate_getptr(p, &len);
int32_t int_val = 0;
ok = upb_enumdef_ntoi(enumdef, buf, len, &int_val);
if (ok) {
upb_selector_t sel = parser_getsel(p);
upb_sink_putint32(&p->top->sink, sel, int_val);
} else {
upb_status_seterrf(p->status, "Enum value unknown: '%.*s'", len, buf);
}
break;
}
default:
assert(false);
upb_status_seterrmsg(p->status, "Internal error in JSON decoder");
ok = false;
break;
}
multipart_end(p);
return ok;
}
static void start_member(upb_json_parser *p) {
assert(!p->top->f);
multipart_startaccum(p);
}
// Helper: invoked during parse_mapentry() to emit the mapentry message's key
// field based on the current contents of the accumulate buffer.
static bool parse_mapentry_key(upb_json_parser *p) {
size_t len;
const char *buf = accumulate_getptr(p, &len);
// Emit the key field. We do a bit of ad-hoc parsing here because the
// parser state machine has already decided that this is a string field
// name, and we are reinterpreting it as some arbitrary key type. In
// particular, integer and bool keys are quoted, so we need to parse the
// quoted string contents here.
p->top->f = upb_msgdef_itof(p->top->m, UPB_MAPENTRY_KEY);
if (p->top->f == NULL) {
upb_status_seterrmsg(p->status, "mapentry message has no key");
return false;
}
switch (upb_fielddef_type(p->top->f)) {
case UPB_TYPE_INT32:
case UPB_TYPE_INT64:
case UPB_TYPE_UINT32:
case UPB_TYPE_UINT64:
// Invoke end_number. The accum buffer has the number's text already.
if (!parse_number(p)) {
return false;
}
break;
case UPB_TYPE_BOOL:
if (len == 4 && !strncmp(buf, "true", 4)) {
if (!parser_putbool(p, true)) {
return false;
}
} else if (len == 5 && !strncmp(buf, "false", 5)) {
if (!parser_putbool(p, false)) {
return false;
}
} else {
upb_status_seterrmsg(p->status,
"Map bool key not 'true' or 'false'");
return false;
}
multipart_end(p);
break;
case UPB_TYPE_STRING:
case UPB_TYPE_BYTES: {
upb_sink subsink;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
upb_sink_startstr(&p->top->sink, sel, len, &subsink);
sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
upb_sink_putstring(&subsink, sel, buf, len, NULL);
sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
upb_sink_endstr(&subsink, sel);
multipart_end(p);
break;
}
default:
upb_status_seterrmsg(p->status, "Invalid field type for map key");
return false;
}
return true;
}
// Helper: emit one map entry (as a submessage in the map field sequence). This
// is invoked from end_membername(), at the end of the map entry's key string,
// with the map key in the accumulate buffer. It parses the key from that
// buffer, emits the handler calls to start the mapentry submessage (setting up
// its subframe in the process), and sets up state in the subframe so that the
// value parser (invoked next) will emit the mapentry's value field and then
// end the mapentry message.
static bool handle_mapentry(upb_json_parser *p) {
// Map entry: p->top->sink is the seq frame, so we need to start a frame
// for the mapentry itself, and then set |f| in that frame so that the map
// value field is parsed, and also set a flag to end the frame after the
// map-entry value is parsed.
if (!check_stack(p)) return false;
const upb_fielddef *mapfield = p->top->mapfield;
const upb_msgdef *mapentrymsg = upb_fielddef_msgsubdef(mapfield);
upb_jsonparser_frame *inner = p->top + 1;
p->top->f = mapfield;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
upb_sink_startsubmsg(&p->top->sink, sel, &inner->sink);
inner->m = mapentrymsg;
inner->mapfield = mapfield;
inner->is_map = false;
// Don't set this to true *yet* -- we reuse parsing handlers below to push
// the key field value to the sink, and these handlers will pop the frame
// if they see is_mapentry (when invoked by the parser state machine, they
// would have just seen the map-entry value, not key).
inner->is_mapentry = false;
p->top = inner;
// send STARTMSG in submsg frame.
upb_sink_startmsg(&p->top->sink);
parse_mapentry_key(p);
// Set up the value field to receive the map-entry value.
p->top->f = upb_msgdef_itof(p->top->m, UPB_MAPENTRY_VALUE);
p->top->is_mapentry = true; // set up to pop frame after value is parsed.
p->top->mapfield = mapfield;
if (p->top->f == NULL) {
upb_status_seterrmsg(p->status, "mapentry message has no value");
return false;
}
return true;
}
static bool end_membername(upb_json_parser *p) {
assert(!p->top->f);
if (p->top->is_map) {
return handle_mapentry(p);
} else {
size_t len;
const char *buf = accumulate_getptr(p, &len);
const upb_fielddef *f = upb_msgdef_ntof(p->top->m, buf, len);
if (!f) {
// TODO(haberman): Ignore unknown fields if requested/configured to do so.
upb_status_seterrf(p->status, "No such field: %.*s\n", (int)len, buf);
return false;
}
p->top->f = f;
multipart_end(p);
return true;
}
}
static void end_member(upb_json_parser *p) {
// If we just parsed a map-entry value, end that frame too.
if (p->top->is_mapentry) {
assert(p->top > p->stack);
// send ENDMSG on submsg.
upb_status s = UPB_STATUS_INIT;
upb_sink_endmsg(&p->top->sink, &s);
const upb_fielddef* mapfield = p->top->mapfield;
// send ENDSUBMSG in repeated-field-of-mapentries frame.
p->top--;
upb_selector_t sel;
bool ok = upb_handlers_getselector(mapfield,
UPB_HANDLER_ENDSUBMSG, &sel);
UPB_ASSERT_VAR(ok, ok);
upb_sink_endsubmsg(&p->top->sink, sel);
}
p->top->f = NULL;
}
static bool start_subobject(upb_json_parser *p) {
assert(p->top->f);
if (upb_fielddef_ismap(p->top->f)) {
// Beginning of a map. Start a new parser frame in a repeated-field
// context.
if (!check_stack(p)) return false;
upb_jsonparser_frame *inner = p->top + 1;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
upb_sink_startseq(&p->top->sink, sel, &inner->sink);
inner->m = upb_fielddef_msgsubdef(p->top->f);
inner->mapfield = p->top->f;
inner->f = NULL;
inner->is_map = true;
inner->is_mapentry = false;
p->top = inner;
return true;
} else if (upb_fielddef_issubmsg(p->top->f)) {
// Beginning of a subobject. Start a new parser frame in the submsg
// context.
if (!check_stack(p)) return false;
upb_jsonparser_frame *inner = p->top + 1;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
upb_sink_startsubmsg(&p->top->sink, sel, &inner->sink);
inner->m = upb_fielddef_msgsubdef(p->top->f);
inner->f = NULL;
inner->is_map = false;
inner->is_mapentry = false;
p->top = inner;
return true;
} else {
upb_status_seterrf(p->status,
"Object specified for non-message/group field: %s",
upb_fielddef_name(p->top->f));
return false;
}
}
static void end_subobject(upb_json_parser *p) {
if (p->top->is_map) {
p->top--;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
upb_sink_endseq(&p->top->sink, sel);
} else {
p->top--;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSUBMSG);
upb_sink_endsubmsg(&p->top->sink, sel);
}
}
static bool start_array(upb_json_parser *p) {
assert(p->top->f);
if (!upb_fielddef_isseq(p->top->f)) {
upb_status_seterrf(p->status,
"Array specified for non-repeated field: %s",
upb_fielddef_name(p->top->f));
return false;
}
if (!check_stack(p)) return false;
upb_jsonparser_frame *inner = p->top + 1;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
upb_sink_startseq(&p->top->sink, sel, &inner->sink);
inner->m = p->top->m;
inner->f = p->top->f;
inner->is_map = false;
inner->is_mapentry = false;
p->top = inner;
return true;
}
static void end_array(upb_json_parser *p) {
assert(p->top > p->stack);
p->top--;
upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
upb_sink_endseq(&p->top->sink, sel);
}
static void start_object(upb_json_parser *p) {
if (!p->top->is_map) {
upb_sink_startmsg(&p->top->sink);
}
}
static void end_object(upb_json_parser *p) {
if (!p->top->is_map) {
upb_status status;
upb_sink_endmsg(&p->top->sink, &status);
}
}
#define CHECK_RETURN_TOP(x) if (!(x)) goto error
/* The actual parser **********************************************************/
// What follows is the Ragel parser itself. The language is specified in Ragel
// and the actions call our C functions above.
//
// Ragel has an extensive set of functionality, and we use only a small part of
// it. There are many action types but we only use a few:
//
// ">" -- transition into a machine
// "%" -- transition out of a machine
// "@" -- transition into a final state of a machine.
//
// "@" transitions are tricky because a machine can transition into a final
// state repeatedly. But in some cases we know this can't happen, for example
// a string which is delimited by a final '"' can only transition into its
// final state once, when the closing '"' is seen.
#line 1151 "upb/json/parser.rl"
#line 1063 "upb/json/parser.c"
static const char _json_actions[] = {
0, 1, 0, 1, 2, 1, 3, 1,
5, 1, 6, 1, 7, 1, 8, 1,
10, 1, 12, 1, 13, 1, 14, 1,
15, 1, 16, 1, 17, 1, 21, 1,
25, 1, 27, 2, 3, 8, 2, 4,
5, 2, 6, 2, 2, 6, 8, 2,
11, 9, 2, 13, 15, 2, 14, 15,
2, 18, 1, 2, 19, 27, 2, 20,
9, 2, 22, 27, 2, 23, 27, 2,
24, 27, 2, 26, 27, 3, 14, 11,
9
};
static const unsigned char _json_key_offsets[] = {
0, 0, 4, 9, 14, 15, 19, 24,
29, 34, 38, 42, 45, 48, 50, 54,
58, 60, 62, 67, 69, 71, 80, 86,
92, 98, 104, 106, 115, 116, 116, 116,
121, 126, 131, 132, 133, 134, 135, 135,
136, 137, 138, 138, 139, 140, 141, 141,
146, 151, 152, 156, 161, 166, 171, 175,
175, 178, 178, 178
};
static const char _json_trans_keys[] = {
32, 123, 9, 13, 32, 34, 125, 9,
13, 32, 34, 125, 9, 13, 34, 32,
58, 9, 13, 32, 93, 125, 9, 13,
32, 44, 125, 9, 13, 32, 44, 125,
9, 13, 32, 34, 9, 13, 45, 48,
49, 57, 48, 49, 57, 46, 69, 101,
48, 57, 69, 101, 48, 57, 43, 45,
48, 57, 48, 57, 48, 57, 46, 69,
101, 48, 57, 34, 92, 34, 92, 34,
47, 92, 98, 102, 110, 114, 116, 117,
48, 57, 65, 70, 97, 102, 48, 57,
65, 70, 97, 102, 48, 57, 65, 70,
97, 102, 48, 57, 65, 70, 97, 102,
34, 92, 34, 45, 91, 102, 110, 116,
123, 48, 57, 34, 32, 93, 125, 9,
13, 32, 44, 93, 9, 13, 32, 93,
125, 9, 13, 97, 108, 115, 101, 117,
108, 108, 114, 117, 101, 32, 34, 125,
9, 13, 32, 34, 125, 9, 13, 34,
32, 58, 9, 13, 32, 93, 125, 9,
13, 32, 44, 125, 9, 13, 32, 44,
125, 9, 13, 32, 34, 9, 13, 32,
9, 13, 0
};
static const char _json_single_lengths[] = {
0, 2, 3, 3, 1, 2, 3, 3,
3, 2, 2, 1, 3, 0, 2, 2,
0, 0, 3, 2, 2, 9, 0, 0,
0, 0, 2, 7, 1, 0, 0, 3,
3, 3, 1, 1, 1, 1, 0, 1,
1, 1, 0, 1, 1, 1, 0, 3,
3, 1, 2, 3, 3, 3, 2, 0,
1, 0, 0, 0
};
static const char _json_range_lengths[] = {
0, 1, 1, 1, 0, 1, 1, 1,
1, 1, 1, 1, 0, 1, 1, 1,
1, 1, 1, 0, 0, 0, 3, 3,
3, 3, 0, 1, 0, 0, 0, 1,
1, 1, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 1,
1, 0, 1, 1, 1, 1, 1, 0,
1, 0, 0, 0
};
static const short _json_index_offsets[] = {
0, 0, 4, 9, 14, 16, 20, 25,
30, 35, 39, 43, 46, 50, 52, 56,
60, 62, 64, 69, 72, 75, 85, 89,
93, 97, 101, 104, 113, 115, 116, 117,
122, 127, 132, 134, 136, 138, 140, 141,
143, 145, 147, 148, 150, 152, 154, 155,
160, 165, 167, 171, 176, 181, 186, 190,
191, 194, 195, 196
};
static const char _json_indicies[] = {
0, 2, 0, 1, 3, 4, 5, 3,
1, 6, 7, 8, 6, 1, 9, 1,
10, 11, 10, 1, 11, 1, 1, 11,
12, 13, 14, 15, 13, 1, 16, 17,
8, 16, 1, 17, 7, 17, 1, 18,
19, 20, 1, 19, 20, 1, 22, 23,
23, 21, 24, 1, 23, 23, 24, 21,
25, 25, 26, 1, 26, 1, 26, 21,
22, 23, 23, 20, 21, 28, 29, 27,
31, 32, 30, 33, 33, 33, 33, 33,
33, 33, 33, 34, 1, 35, 35, 35,
1, 36, 36, 36, 1, 37, 37, 37,
1, 38, 38, 38, 1, 40, 41, 39,
42, 43, 44, 45, 46, 47, 48, 43,
1, 49, 1, 50, 51, 53, 54, 1,
53, 52, 55, 56, 54, 55, 1, 56,
1, 1, 56, 52, 57, 1, 58, 1,
59, 1, 60, 1, 61, 62, 1, 63,
1, 64, 1, 65, 66, 1, 67, 1,
68, 1, 69, 70, 71, 72, 70, 1,
73, 74, 75, 73, 1, 76, 1, 77,
78, 77, 1, 78, 1, 1, 78, 79,
80, 81, 82, 80, 1, 83, 84, 75,
83, 1, 84, 74, 84, 1, 85, 86,
86, 1, 1, 1, 1, 0
};
static const char _json_trans_targs[] = {
1, 0, 2, 3, 4, 56, 3, 4,
56, 5, 5, 6, 7, 8, 9, 56,
8, 9, 11, 12, 18, 57, 13, 15,
14, 16, 17, 20, 58, 21, 20, 58,
21, 19, 22, 23, 24, 25, 26, 20,
58, 21, 28, 30, 31, 34, 39, 43,
47, 29, 59, 59, 32, 31, 29, 32,
33, 35, 36, 37, 38, 59, 40, 41,
42, 59, 44, 45, 46, 59, 48, 49,
55, 48, 49, 55, 50, 50, 51, 52,
53, 54, 55, 53, 54, 59, 56
};
static const char _json_trans_actions[] = {
0, 0, 0, 21, 77, 53, 0, 47,
23, 17, 0, 0, 15, 19, 19, 50,
0, 0, 0, 0, 0, 1, 0, 0,
0, 0, 0, 3, 13, 0, 0, 35,
5, 11, 0, 38, 7, 7, 7, 41,
44, 9, 62, 56, 25, 0, 0, 0,
31, 29, 33, 59, 15, 0, 27, 0,
0, 0, 0, 0, 0, 68, 0, 0,
0, 71, 0, 0, 0, 65, 21, 77,
53, 0, 47, 23, 17, 0, 0, 15,
19, 19, 50, 0, 0, 74, 0
};
static const int json_start = 1;
static const int json_en_number_machine = 10;
static const int json_en_string_machine = 19;
static const int json_en_value_machine = 27;
static const int json_en_main = 1;
#line 1154 "upb/json/parser.rl"
size_t parse(void *closure, const void *hd, const char *buf, size_t size,
const upb_bufhandle *handle) {
UPB_UNUSED(hd);
UPB_UNUSED(handle);
upb_json_parser *parser = closure;
parser->handle = handle;
// Variables used by Ragel's generated code.
int cs = parser->current_state;
int *stack = parser->parser_stack;
int top = parser->parser_top;
const char *p = buf;
const char *pe = buf + size;
capture_resume(parser, buf);
#line 1232 "upb/json/parser.c"
{
int _klen;
unsigned int _trans;
const char *_acts;
unsigned int _nacts;
const char *_keys;
if ( p == pe )
goto _test_eof;
if ( cs == 0 )
goto _out;
_resume:
_keys = _json_trans_keys + _json_key_offsets[cs];
_trans = _json_index_offsets[cs];
_klen = _json_single_lengths[cs];
if ( _klen > 0 ) {
const char *_lower = _keys;
const char *_mid;
const char *_upper = _keys + _klen - 1;
while (1) {
if ( _upper < _lower )
break;
_mid = _lower + ((_upper-_lower) >> 1);
if ( (*p) < *_mid )
_upper = _mid - 1;
else if ( (*p) > *_mid )
_lower = _mid + 1;
else {
_trans += (unsigned int)(_mid - _keys);
goto _match;
}
}
_keys += _klen;
_trans += _klen;
}
_klen = _json_range_lengths[cs];
if ( _klen > 0 ) {
const char *_lower = _keys;
const char *_mid;
const char *_upper = _keys + (_klen<<1) - 2;
while (1) {
if ( _upper < _lower )
break;
_mid = _lower + (((_upper-_lower) >> 1) & ~1);
if ( (*p) < _mid[0] )
_upper = _mid - 2;
else if ( (*p) > _mid[1] )
_lower = _mid + 2;
else {
_trans += (unsigned int)((_mid - _keys)>>1);
goto _match;
}
}
_trans += _klen;
}
_match:
_trans = _json_indicies[_trans];
cs = _json_trans_targs[_trans];
if ( _json_trans_actions[_trans] == 0 )
goto _again;
_acts = _json_actions + _json_trans_actions[_trans];
_nacts = (unsigned int) *_acts++;
while ( _nacts-- > 0 )
{
switch ( *_acts++ )
{
case 0:
#line 1066 "upb/json/parser.rl"
{ p--; {cs = stack[--top]; goto _again;} }
break;
case 1:
#line 1067 "upb/json/parser.rl"
{ p--; {stack[top++] = cs; cs = 10; goto _again;} }
break;
case 2:
#line 1071 "upb/json/parser.rl"
{ start_text(parser, p); }
break;
case 3:
#line 1072 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(end_text(parser, p)); }
break;
case 4:
#line 1078 "upb/json/parser.rl"
{ start_hex(parser); }
break;
case 5:
#line 1079 "upb/json/parser.rl"
{ hexdigit(parser, p); }
break;
case 6:
#line 1080 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(end_hex(parser)); }
break;
case 7:
#line 1086 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(escape(parser, p)); }
break;
case 8:
#line 1092 "upb/json/parser.rl"
{ p--; {cs = stack[--top]; goto _again;} }
break;
case 9:
#line 1095 "upb/json/parser.rl"
{ {stack[top++] = cs; cs = 19; goto _again;} }
break;
case 10:
#line 1097 "upb/json/parser.rl"
{ p--; {stack[top++] = cs; cs = 27; goto _again;} }
break;
case 11:
#line 1102 "upb/json/parser.rl"
{ start_member(parser); }
break;
case 12:
#line 1103 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(end_membername(parser)); }
break;
case 13:
#line 1106 "upb/json/parser.rl"
{ end_member(parser); }
break;
case 14:
#line 1112 "upb/json/parser.rl"
{ start_object(parser); }
break;
case 15:
#line 1115 "upb/json/parser.rl"
{ end_object(parser); }
break;
case 16:
#line 1121 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(start_array(parser)); }
break;
case 17:
#line 1125 "upb/json/parser.rl"
{ end_array(parser); }
break;
case 18:
#line 1130 "upb/json/parser.rl"
{ start_number(parser, p); }
break;
case 19:
#line 1131 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(end_number(parser, p)); }
break;
case 20:
#line 1133 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(start_stringval(parser)); }
break;
case 21:
#line 1134 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(end_stringval(parser)); }
break;
case 22:
#line 1136 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(parser_putbool(parser, true)); }
break;
case 23:
#line 1138 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(parser_putbool(parser, false)); }
break;
case 24:
#line 1140 "upb/json/parser.rl"
{ /* null value */ }
break;
case 25:
#line 1142 "upb/json/parser.rl"
{ CHECK_RETURN_TOP(start_subobject(parser)); }
break;
case 26:
#line 1143 "upb/json/parser.rl"
{ end_subobject(parser); }
break;
case 27:
#line 1148 "upb/json/parser.rl"
{ p--; {cs = stack[--top]; goto _again;} }
break;
#line 1418 "upb/json/parser.c"
}
}
_again:
if ( cs == 0 )
goto _out;
if ( ++p != pe )
goto _resume;
_test_eof: {}
_out: {}
}
#line 1173 "upb/json/parser.rl"
if (p != pe) {
upb_status_seterrf(parser->status, "Parse error at %s\n", p);
} else {
capture_suspend(parser, &p);
}
error:
// Save parsing state back to parser.
parser->current_state = cs;
parser->parser_top = top;
return p - buf;
}
bool end(void *closure, const void *hd) {
UPB_UNUSED(closure);
UPB_UNUSED(hd);
// Prevent compile warning on unused static constants.
UPB_UNUSED(json_start);
UPB_UNUSED(json_en_number_machine);
UPB_UNUSED(json_en_string_machine);
UPB_UNUSED(json_en_value_machine);
UPB_UNUSED(json_en_main);
return true;
}
static void json_parser_reset(upb_json_parser *p) {
p->top = p->stack;
p->top->f = NULL;
p->top->is_map = false;
p->top->is_mapentry = false;
int cs;
int top;
// Emit Ragel initialization of the parser.
#line 1470 "upb/json/parser.c"
{
cs = json_start;
top = 0;
}
#line 1211 "upb/json/parser.rl"
p->current_state = cs;
p->parser_top = top;
accumulate_clear(p);
p->multipart_state = MULTIPART_INACTIVE;
p->capture = NULL;
p->accumulated = NULL;
}
/* Public API *****************************************************************/
upb_json_parser *upb_json_parser_create(upb_env *env, upb_sink *output) {
#ifndef NDEBUG
const size_t size_before = upb_env_bytesallocated(env);
#endif
upb_json_parser *p = upb_env_malloc(env, sizeof(upb_json_parser));
if (!p) return false;
p->env = env;
p->limit = p->stack + UPB_JSON_MAX_DEPTH;
p->accumulate_buf = NULL;
p->accumulate_buf_size = 0;
upb_byteshandler_init(&p->input_handler_);
upb_byteshandler_setstring(&p->input_handler_, parse, NULL);
upb_byteshandler_setendstr(&p->input_handler_, end, NULL);
upb_bytessink_reset(&p->input_, &p->input_handler_, p);
json_parser_reset(p);
upb_sink_reset(&p->top->sink, output->handlers, output->closure);
p->top->m = upb_handlers_msgdef(output->handlers);
// If this fails, uncomment and increase the value in parser.h.
// fprintf(stderr, "%zd\n", upb_env_bytesallocated(env) - size_before);
assert(upb_env_bytesallocated(env) - size_before <= UPB_JSON_PARSER_SIZE);
return p;
}
upb_bytessink *upb_json_parser_input(upb_json_parser *p) {
return &p->input_;
}