Protocol Buffers - Google's data interchange format (grpc依赖) https://developers.google.com/protocol-buffers/
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/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2008-2011 Google Inc. See LICENSE for details.
* Author: Josh Haberman <jhaberman@gmail.com>
*/
#include <inttypes.h>
#include <stddef.h>
#include <stdlib.h>
#include "upb/bytestream.h"
#include "upb/pb/decoder.h"
#include "upb/pb/varint.h"
typedef struct {
uint8_t native_wire_type;
bool is_numeric;
} upb_decoder_typeinfo;
static const upb_decoder_typeinfo upb_decoder_types[] = {
{UPB_WIRE_TYPE_END_GROUP, false}, // ENDGROUP
{UPB_WIRE_TYPE_64BIT, true}, // DOUBLE
{UPB_WIRE_TYPE_32BIT, true}, // FLOAT
{UPB_WIRE_TYPE_VARINT, true}, // INT64
{UPB_WIRE_TYPE_VARINT, true}, // UINT64
{UPB_WIRE_TYPE_VARINT, true}, // INT32
{UPB_WIRE_TYPE_64BIT, true}, // FIXED64
{UPB_WIRE_TYPE_32BIT, true}, // FIXED32
{UPB_WIRE_TYPE_VARINT, true}, // BOOL
{UPB_WIRE_TYPE_DELIMITED, false}, // STRING
{UPB_WIRE_TYPE_START_GROUP, false}, // GROUP
{UPB_WIRE_TYPE_DELIMITED, false}, // MESSAGE
{UPB_WIRE_TYPE_DELIMITED, false}, // BYTES
{UPB_WIRE_TYPE_VARINT, true}, // UINT32
{UPB_WIRE_TYPE_VARINT, true}, // ENUM
{UPB_WIRE_TYPE_32BIT, true}, // SFIXED32
{UPB_WIRE_TYPE_64BIT, true}, // SFIXED64
{UPB_WIRE_TYPE_VARINT, true}, // SINT32
{UPB_WIRE_TYPE_VARINT, true}, // SINT64
};
/* upb_decoderplan ************************************************************/
#ifdef UPB_USE_JIT_X64
// These defines are necessary for DynASM codegen.
// See dynasm/dasm_proto.h for more info.
#define Dst_DECL upb_decoderplan *plan
#define Dst_REF (plan->dynasm)
#define Dst (plan)
// In debug mode, make DynASM do internal checks (must be defined before any
// dasm header is included.
#ifndef NDEBUG
#define DASM_CHECKS
#endif
#include "dynasm/dasm_proto.h"
#include "upb/pb/decoder_x64.h"
#endif
upb_decoderplan *upb_decoderplan_new(const upb_handlers *h, bool allowjit) {
UPB_UNUSED(allowjit);
upb_decoderplan *p = malloc(sizeof(*p));
assert(upb_handlers_isfrozen(h));
p->handlers = h;
upb_handlers_ref(h, p);
#ifdef UPB_USE_JIT_X64
p->jit_code = NULL;
if (allowjit) upb_decoderplan_makejit(p);
#endif
return p;
}
void upb_decoderplan_unref(upb_decoderplan *p) {
// TODO: make truly refcounted.
upb_handlers_unref(p->handlers, p);
#ifdef UPB_USE_JIT_X64
if (p->jit_code) upb_decoderplan_freejit(p);
#endif
free(p);
}
bool upb_decoderplan_hasjitcode(upb_decoderplan *p) {
#ifdef UPB_USE_JIT_X64
return p->jit_code != NULL;
#else
(void)p;
return false;
#endif
}
/* upb_decoder ****************************************************************/
// It's unfortunate that we have to micro-manage the compiler this way,
// especially since this tuning is necessarily specific to one hardware
// configuration. But emperically on a Core i7, performance increases 30-50%
// with these annotations. Every instance where these appear, gcc 4.2.1 made
// the wrong decision and degraded performance in benchmarks.
#define FORCEINLINE static inline __attribute__((always_inline))
#define NOINLINE static __attribute__((noinline))
UPB_NORETURN static void upb_decoder_exitjmp(upb_decoder *d) {
// Resumable decoder would back out to completed_ptr (and possibly get a
// previous buffer).
_longjmp(d->exitjmp, 1);
}
UPB_NORETURN static void upb_decoder_exitjmp2(void *d) {
upb_decoder_exitjmp(d);
}
UPB_NORETURN static void upb_decoder_abortjmp(upb_decoder *d, const char *msg) {
upb_status_seterrliteral(&d->status, msg);
upb_decoder_exitjmp(d);
}
/* Buffering ******************************************************************/
// We operate on one buffer at a time, which may be a subset of the currently
// loaded byteregion data. When data for the buffer is completely gone we pull
// the next one. When we've committed our progress we discard any previous
// buffers' regions.
static size_t upb_decoder_bufleft(upb_decoder *d) {
assert(d->end >= d->ptr);
return d->end - d->ptr;
}
static void upb_decoder_advance(upb_decoder *d, size_t len) {
assert(upb_decoder_bufleft(d) >= len);
d->ptr += len;
}
uint64_t upb_decoder_offset(upb_decoder *d) {
return d->bufstart_ofs + (d->ptr - d->buf);
}
uint64_t upb_decoder_bufendofs(upb_decoder *d) {
return d->bufstart_ofs + (d->end - d->buf);
}
static bool upb_decoder_islegalend(upb_decoder *d) {
if (d->top == d->stack) return true;
if (d->top - 1 == d->stack &&
d->top->is_sequence && !d->top->is_packed) return true;
return false;
}
// Calculates derived values that we cache for speed. These reflect a
// combination of the current buffer and the stack, so must be called whenever
// either is updated.
static void upb_decoder_setmsgend(upb_decoder *d) {
upb_decoder_frame *f = d->top;
size_t delimlen = f->end_ofs - d->bufstart_ofs;
size_t buflen = d->end - d->buf;
d->delim_end = (f->end_ofs != UPB_NONDELIMITED && delimlen <= buflen) ?
d->buf + delimlen : NULL; // NULL if not in this buf.
d->top_is_packed = f->is_packed;
}
static void upb_decoder_skiptonewbuf(upb_decoder *d, uint64_t ofs) {
assert(ofs >= upb_decoder_offset(d));
if (ofs > upb_byteregion_endofs(d->input))
upb_decoder_abortjmp(d, "Unexpected EOF");
d->buf = NULL;
d->ptr = NULL;
d->end = NULL;
d->delim_end = NULL;
#ifdef UPB_USE_JIT_X64
d->jit_end = NULL;
#endif
d->bufstart_ofs = ofs;
}
static bool upb_trypullbuf(upb_decoder *d) {
assert(upb_decoder_bufleft(d) == 0);
upb_decoder_skiptonewbuf(d, upb_decoder_offset(d));
if (upb_byteregion_available(d->input, d->bufstart_ofs) == 0) {
switch (upb_byteregion_fetch(d->input)) {
case UPB_BYTE_OK:
assert(upb_byteregion_available(d->input, d->bufstart_ofs) > 0);
break;
case UPB_BYTE_EOF: return false;
case UPB_BYTE_ERROR: upb_decoder_abortjmp(d, "I/O error in input");
// Decoder resuming is not yet supported.
case UPB_BYTE_WOULDBLOCK:
upb_decoder_abortjmp(d, "Input returned WOULDBLOCK");
}
}
size_t len;
d->buf = upb_byteregion_getptr(d->input, d->bufstart_ofs, &len);
assert(len > 0);
d->ptr = d->buf;
d->end = d->buf + len;
upb_decoder_setmsgend(d);
#ifdef UPB_USE_JIT_X64
// If we start parsing a value, we can parse up to 20 bytes without
// having to bounds-check anything (2 10-byte varints). Since the
// JIT bounds-checks only *between* values (and for strings), the
// JIT bails if there are not 20 bytes available.
d->jit_end = d->end - 20;
#endif
assert(upb_decoder_bufleft(d) > 0);
return true;
}
static void upb_pullbuf(upb_decoder *d) {
if (!upb_trypullbuf(d)) upb_decoder_abortjmp(d, "Unexpected EOF");
}
static void upb_decoder_checkpoint(upb_decoder *d) {
upb_byteregion_discard(d->input, upb_decoder_offset(d));
}
static void upb_decoder_discardto(upb_decoder *d, uint64_t ofs) {
if (ofs <= upb_decoder_bufendofs(d)) {
upb_decoder_advance(d, ofs - upb_decoder_offset(d));
} else {
upb_decoder_skiptonewbuf(d, ofs);
}
upb_decoder_checkpoint(d);
}
static void upb_decoder_discard(upb_decoder *d, size_t bytes) {
upb_decoder_discardto(d, upb_decoder_offset(d) + bytes);
}
/* Decoding of wire types *****************************************************/
NOINLINE uint64_t upb_decode_varint_slow(upb_decoder *d) {
uint8_t byte = 0x80;
uint64_t u64 = 0;
int bitpos;
for(bitpos = 0; bitpos < 70 && (byte & 0x80); bitpos += 7) {
if (upb_decoder_bufleft(d) == 0) upb_pullbuf(d);
u64 |= ((uint64_t)(byte = *d->ptr) & 0x7F) << bitpos;
upb_decoder_advance(d, 1);
}
if(bitpos == 70 && (byte & 0x80))
upb_decoder_abortjmp(d, "Unterminated varint");
return u64;
}
// For tags and delimited lengths, which must be <=32bit and are usually small.
FORCEINLINE uint32_t upb_decode_varint32(upb_decoder *d) {
const char *p = d->ptr;
uint32_t ret;
uint64_t u64;
// Nearly all will be either 1 byte (1-16) or 2 bytes (17-2048).
if (upb_decoder_bufleft(d) < 2) goto slow; // unlikely.
ret = *p & 0x7f;
if ((*(p++) & 0x80) == 0) goto done; // predictable if fields are in order
ret |= (*p & 0x7f) << 7;
if ((*(p++) & 0x80) == 0) goto done; // likely
slow:
u64 = upb_decode_varint_slow(d);
if (u64 > UINT32_MAX) upb_decoder_abortjmp(d, "Unterminated 32-bit varint");
ret = (uint32_t)u64;
p = d->ptr; // Turn the next line into a nop.
done:
upb_decoder_advance(d, p - d->ptr);
return ret;
}
// Returns true on success or false if we've hit a valid EOF.
FORCEINLINE bool upb_trydecode_varint32(upb_decoder *d, uint32_t *val) {
if (upb_decoder_bufleft(d) == 0 &&
upb_decoder_islegalend(d) &&
!upb_trypullbuf(d)) {
return false;
}
*val = upb_decode_varint32(d);
return true;
}
FORCEINLINE uint64_t upb_decode_varint(upb_decoder *d) {
if (upb_decoder_bufleft(d) >= 10) {
// Fast case.
upb_decoderet r = upb_vdecode_fast(d->ptr);
if (r.p == NULL) upb_decoder_abortjmp(d, "Unterminated varint");
upb_decoder_advance(d, r.p - d->ptr);
return r.val;
} else if (upb_decoder_bufleft(d) > 0) {
// Intermediate case -- worth it?
char tmpbuf[10];
memset(tmpbuf, 0x80, 10);
memcpy(tmpbuf, d->ptr, upb_decoder_bufleft(d));
upb_decoderet r = upb_vdecode_fast(tmpbuf);
if (r.p != NULL) {
upb_decoder_advance(d, r.p - tmpbuf);
return r.val;
}
}
// Slow case -- varint spans buffer seam.
return upb_decode_varint_slow(d);
}
FORCEINLINE void upb_decode_fixed(upb_decoder *d, char *buf, size_t bytes) {
if (upb_decoder_bufleft(d) >= bytes) {
// Fast case.
memcpy(buf, d->ptr, bytes);
upb_decoder_advance(d, bytes);
} else {
// Slow case.
size_t read = 0;
while (1) {
size_t avail = UPB_MIN(upb_decoder_bufleft(d), bytes - read);
memcpy(buf + read, d->ptr, avail);
upb_decoder_advance(d, avail);
read += avail;
if (read == bytes) break;
upb_pullbuf(d);
}
}
}
FORCEINLINE uint32_t upb_decode_fixed32(upb_decoder *d) {
uint32_t u32;
upb_decode_fixed(d, (char*)&u32, sizeof(uint32_t));
return u32; // TODO: proper byte swapping for big-endian machines.
}
FORCEINLINE uint64_t upb_decode_fixed64(upb_decoder *d) {
uint64_t u64;
upb_decode_fixed(d, (char*)&u64, sizeof(uint64_t));
return u64; // TODO: proper byte swapping for big-endian machines.
}
INLINE void upb_push_msg(upb_decoder *d, const upb_fielddef *f, uint64_t end) {
upb_decoder_frame *fr = d->top + 1;
if (!upb_sink_startsubmsg(&d->sink, f) || fr > d->limit) {
upb_decoder_abortjmp(d, "Nesting too deep.");
}
fr->f = f;
fr->is_sequence = false;
fr->is_packed = false;
fr->end_ofs = end;
fr->group_fieldnum = end == UPB_NONDELIMITED ?
(int32_t)upb_fielddef_number(f) : -1;
d->top = fr;
upb_decoder_setmsgend(d);
}
INLINE void upb_push_seq(upb_decoder *d, const upb_fielddef *f, bool packed,
uint64_t end_ofs) {
upb_decoder_frame *fr = d->top + 1;
if (!upb_sink_startseq(&d->sink, f) || fr > d->limit) {
upb_decoder_abortjmp(d, "Nesting too deep.");
}
fr->f = f;
fr->is_sequence = true;
fr->group_fieldnum = -1;
fr->is_packed = packed;
fr->end_ofs = end_ofs;
d->top = fr;
upb_decoder_setmsgend(d);
}
INLINE void upb_pop_submsg(upb_decoder *d) {
upb_sink_endsubmsg(&d->sink, d->top->f);
d->top--;
upb_decoder_setmsgend(d);
}
INLINE void upb_pop_seq(upb_decoder *d) {
upb_sink_endseq(&d->sink, d->top->f);
d->top--;
upb_decoder_setmsgend(d);
}
/* Decoding of .proto types ***************************************************/
// Technically, we are losing data if we see a 32-bit varint that is not
// properly sign-extended. We could detect this and error about the data loss,
// but proto2 does not do this, so we pass.
#define T(type, wt, name, convfunc) \
INLINE void upb_decode_ ## type(upb_decoder *d, const upb_fielddef *f) { \
upb_sink_put ## name(&d->sink, f, (convfunc)(upb_decode_ ## wt(d))); \
} \
static double upb_asdouble(uint64_t n) { double d; memcpy(&d, &n, 8); return d; }
static float upb_asfloat(uint32_t n) { float f; memcpy(&f, &n, 4); return f; }
T(INT32, varint, int32, int32_t)
T(INT64, varint, int64, int64_t)
T(UINT32, varint, uint32, uint32_t)
T(UINT64, varint, uint64, uint64_t)
T(FIXED32, fixed32, uint32, uint32_t)
T(FIXED64, fixed64, uint64, uint64_t)
T(SFIXED32, fixed32, int32, int32_t)
T(SFIXED64, fixed64, int64, int64_t)
T(BOOL, varint, bool, bool)
T(ENUM, varint, int32, int32_t)
T(DOUBLE, fixed64, double, upb_asdouble)
T(FLOAT, fixed32, float, upb_asfloat)
T(SINT32, varint, int32, upb_zzdec_32)
T(SINT64, varint, int64, upb_zzdec_64)
#undef T
static void upb_decode_GROUP(upb_decoder *d, const upb_fielddef *f) {
upb_push_msg(d, f, UPB_NONDELIMITED);
}
static void upb_decode_MESSAGE(upb_decoder *d, const upb_fielddef *f) {
uint32_t len = upb_decode_varint32(d);
upb_push_msg(d, f, upb_decoder_offset(d) + len);
}
static void upb_decode_STRING(upb_decoder *d, const upb_fielddef *f) {
uint32_t strlen = upb_decode_varint32(d);
uint64_t offset = upb_decoder_offset(d);
uint64_t end = offset + strlen;
if (end > upb_byteregion_endofs(d->input))
upb_decoder_abortjmp(d, "Unexpected EOF");
upb_sink_startstr(&d->sink, f, strlen);
while (strlen > 0) {
if (upb_byteregion_available(d->input, offset) == 0)
upb_pullbuf(d);
size_t len;
const char *ptr = upb_byteregion_getptr(d->input, offset, &len);
len = UPB_MIN(len, strlen);
len = upb_sink_putstring(&d->sink, f, ptr, len);
if (len > strlen)
upb_decoder_abortjmp(d, "Skipped too many bytes.");
offset += len;
strlen -= len;
upb_decoder_discardto(d, offset);
}
upb_sink_endstr(&d->sink, f);
}
/* The main decoding loop *****************************************************/
static void upb_decoder_checkdelim(upb_decoder *d) {
// TODO: This doesn't work for the case that no buffer is currently loaded
// (ie. d->buf == NULL) because delim_end is NULL even if we are at
// end-of-delim. Need to add a test that exercises this by putting a buffer
// seam in the middle of the final delimited value in a proto that we skip
// for some reason (like because it's unknown and we have no unknown field
// handler).
while (d->delim_end != NULL && d->ptr >= d->delim_end) {
if (d->ptr > d->delim_end) upb_decoder_abortjmp(d, "Bad submessage end");
if (d->top->is_sequence) {
upb_pop_seq(d);
} else {
upb_pop_submsg(d);
}
}
}
INLINE const upb_fielddef *upb_decode_tag(upb_decoder *d) {
while (1) {
uint32_t tag;
if (!upb_trydecode_varint32(d, &tag)) return NULL;
uint8_t wire_type = tag & 0x7;
uint32_t fieldnum = tag >> 3; const upb_fielddef *f = NULL;
const upb_handlers *h = upb_sink_tophandlers(&d->sink);
f = upb_msgdef_itof(upb_handlers_msgdef(h), fieldnum);
bool packed = false;
if (f) {
// Wire type check.
upb_fieldtype_t type = upb_fielddef_type(f);
if (wire_type == upb_decoder_types[type].native_wire_type) {
// Wire type is ok.
} else if ((wire_type == UPB_WIRE_TYPE_DELIMITED &&
upb_decoder_types[type].is_numeric)) {
// Wire type is ok (and packed).
packed = true;
} else {
f = NULL;
}
}
// There are no explicit "startseq" or "endseq" markers in protobuf
// streams, so we have to infer them by noticing when a repeated field
// starts or ends.
upb_decoder_frame *fr = d->top;
if (fr->is_sequence && fr->f != f) {
upb_pop_seq(d);
fr = d->top;
}
if (f && upb_fielddef_isseq(f) && !fr->is_sequence) {
if (packed) {
uint32_t len = upb_decode_varint32(d);
upb_push_seq(d, f, true, upb_decoder_offset(d) + len);
} else {
upb_push_seq(d, f, false, fr->end_ofs);
}
}
if (f) return f;
// Unknown field or ENDGROUP.
if (fieldnum == 0 || fieldnum > UPB_MAX_FIELDNUMBER)
upb_decoder_abortjmp(d, "Invalid field number");
switch (wire_type) {
case UPB_WIRE_TYPE_VARINT: upb_decode_varint(d); break;
case UPB_WIRE_TYPE_32BIT: upb_decoder_discard(d, 4); break;
case UPB_WIRE_TYPE_64BIT: upb_decoder_discard(d, 8); break;
case UPB_WIRE_TYPE_DELIMITED:
upb_decoder_discard(d, upb_decode_varint32(d)); break;
case UPB_WIRE_TYPE_START_GROUP:
upb_decoder_abortjmp(d, "Can't handle unknown groups yet");
case UPB_WIRE_TYPE_END_GROUP:
if (fieldnum != fr->group_fieldnum)
upb_decoder_abortjmp(d, "Unmatched ENDGROUP tag");
upb_sink_endsubmsg(&d->sink, fr->f);
d->top--;
upb_decoder_setmsgend(d);
break;
default:
upb_decoder_abortjmp(d, "Invalid wire type");
}
// TODO: deliver to unknown field callback.
upb_decoder_checkpoint(d);
upb_decoder_checkdelim(d);
}
}
upb_success_t upb_decoder_decode(upb_decoder *d) {
assert(d->input);
if (_setjmp(d->exitjmp)) {
assert(!upb_ok(&d->status));
return UPB_ERROR;
}
upb_sink_startmsg(&d->sink);
// Prime the buf so we can hit the JIT immediately.
upb_trypullbuf(d);
const upb_fielddef *f = d->top->f;
while(1) {
#ifdef UPB_USE_JIT_X64
upb_decoder_enterjit(d);
upb_decoder_checkpoint(d);
upb_decoder_setmsgend(d);
#endif
upb_decoder_checkdelim(d);
if (!d->top_is_packed) f = upb_decode_tag(d);
if (!f) {
// Sucessful EOF. We may need to dispatch a top-level implicit frame.
if (d->top->is_sequence) {
assert(d->sink.top == d->sink.stack + 1);
upb_pop_seq(d);
}
assert(d->top == d->stack);
upb_sink_endmsg(&d->sink, &d->status);
return UPB_OK;
}
switch (upb_fielddef_type(f)) {
case UPB_TYPE(DOUBLE): upb_decode_DOUBLE(d, f); break;
case UPB_TYPE(FLOAT): upb_decode_FLOAT(d, f); break;
case UPB_TYPE(INT64): upb_decode_INT64(d, f); break;
case UPB_TYPE(UINT64): upb_decode_UINT64(d, f); break;
case UPB_TYPE(INT32): upb_decode_INT32(d, f); break;
case UPB_TYPE(FIXED64): upb_decode_FIXED64(d, f); break;
case UPB_TYPE(FIXED32): upb_decode_FIXED32(d, f); break;
case UPB_TYPE(BOOL): upb_decode_BOOL(d, f); break;
case UPB_TYPE(STRING):
case UPB_TYPE(BYTES): upb_decode_STRING(d, f); break;
case UPB_TYPE(GROUP): upb_decode_GROUP(d, f); break;
case UPB_TYPE(MESSAGE): upb_decode_MESSAGE(d, f); break;
case UPB_TYPE(UINT32): upb_decode_UINT32(d, f); break;
case UPB_TYPE(ENUM): upb_decode_ENUM(d, f); break;
case UPB_TYPE(SFIXED32): upb_decode_SFIXED32(d, f); break;
case UPB_TYPE(SFIXED64): upb_decode_SFIXED64(d, f); break;
case UPB_TYPE(SINT32): upb_decode_SINT32(d, f); break;
case UPB_TYPE(SINT64): upb_decode_SINT64(d, f); break;
case UPB_TYPE_NONE: assert(false); break;
}
upb_decoder_checkpoint(d);
}
}
void upb_decoder_init(upb_decoder *d) {
upb_status_init(&d->status);
d->plan = NULL;
d->input = NULL;
d->limit = &d->stack[UPB_MAX_NESTING];
}
void upb_decoder_resetplan(upb_decoder *d, upb_decoderplan *p) {
d->plan = p;
d->input = NULL;
upb_sink_init(&d->sink, p->handlers);
}
void upb_decoder_resetinput(upb_decoder *d, upb_byteregion *input,
void *c) {
assert(d->plan);
upb_status_clear(&d->status);
upb_sink_reset(&d->sink, c);
d->input = input;
d->top = d->stack;
d->top->is_sequence = false;
d->top->is_packed = false;
d->top->group_fieldnum = UINT32_MAX;
d->top->end_ofs = UPB_NONDELIMITED;
// Protect against assert in skiptonewbuf().
d->bufstart_ofs = 0;
d->ptr = NULL;
d->buf = NULL;
upb_decoder_skiptonewbuf(d, upb_byteregion_startofs(input));
}
void upb_decoder_uninit(upb_decoder *d) {
upb_status_uninit(&d->status);
}