mirror of
https://github.com/vee1e/flatbuffers.git
synced 2026-09-05 03:37:29 +00:00
541b06759f
This happens when the schema is parsed, to avoid compile time errors later, which would be harder to understand. Bug: 16325216 Change-Id: I24cabf1adaf1700796b91e3a9641bca43a68bfbd Tested: on OS X.
964 lines
34 KiB
C++
964 lines
34 KiB
C++
/*
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* Copyright 2014 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <algorithm>
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#include "flatbuffers/flatbuffers.h"
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#include "flatbuffers/idl.h"
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#include "flatbuffers/util.h"
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namespace flatbuffers {
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const char *const kTypeNames[] = {
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#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) IDLTYPE,
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FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
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#undef FLATBUFFERS_TD
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nullptr
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};
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const char kTypeSizes[] = {
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#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) sizeof(CTYPE),
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FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
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#undef FLATBUFFERS_TD
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};
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static void Error(const std::string &msg) {
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throw msg;
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}
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// Ensure that integer values we parse fit inside the declared integer type.
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static void CheckBitsFit(int64_t val, size_t bits) {
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auto mask = (1ll << bits) - 1; // Bits we allow to be used.
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if (bits < 64 &&
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(val & ~mask) != 0 && // Positive or unsigned.
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(val | mask) != -1) // Negative.
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Error("constant does not fit in a " + NumToString(bits) + "-bit field");
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}
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// atot: templated version of atoi/atof: convert a string to an instance of T.
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template<typename T> inline T atot(const char *s) {
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auto val = StringToInt(s);
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CheckBitsFit(val, sizeof(T) * 8);
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return (T)val;
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}
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template<> inline bool atot<bool>(const char *s) {
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return 0 != atoi(s);
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}
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template<> inline float atot<float>(const char *s) {
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return static_cast<float>(strtod(s, nullptr));
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}
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template<> inline double atot<double>(const char *s) {
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return strtod(s, nullptr);
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}
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template<> inline Offset<void> atot<Offset<void>>(const char *s) {
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return Offset<void>(atoi(s));
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}
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// Declare tokens we'll use. Single character tokens are represented by their
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// ascii character code (e.g. '{'), others above 256.
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#define FLATBUFFERS_GEN_TOKENS(TD) \
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TD(Eof, 256, "end of file") \
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TD(StringConstant, 257, "string constant") \
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TD(IntegerConstant, 258, "integer constant") \
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TD(FloatConstant, 259, "float constant") \
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TD(Identifier, 260, "identifier") \
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TD(Table, 261, "table") \
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TD(Struct, 262, "struct") \
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TD(Enum, 263, "enum") \
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TD(Union, 264, "union") \
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TD(NameSpace, 265, "namespace") \
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TD(RootType, 266, "root_type") \
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TD(FileIdentifier, 267, "file_identifier") \
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TD(FileExtension, 268, "file_extension") \
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TD(Include, 269, "include")
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#ifdef __GNUC__
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__extension__ // Stop GCC complaining about trailing comma with -Wpendantic.
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#endif
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enum {
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#define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) kToken ## NAME = VALUE,
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FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
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#undef FLATBUFFERS_TOKEN
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#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) kToken ## ENUM,
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FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
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#undef FLATBUFFERS_TD
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};
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static std::string TokenToString(int t) {
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static const char *tokens[] = {
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#define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) STRING,
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FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
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#undef FLATBUFFERS_TOKEN
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#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) IDLTYPE,
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FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
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#undef FLATBUFFERS_TD
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};
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if (t < 256) { // A single ascii char token.
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std::string s;
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s.append(1, t);
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return s;
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} else { // Other tokens.
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return tokens[t - 256];
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}
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}
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// Parses exactly nibbles worth of hex digits into a number, or error.
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int64_t Parser::ParseHexNum(int nibbles) {
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for (int i = 0; i < nibbles; i++)
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if (!isxdigit(cursor_[i]))
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Error("escape code must be followed by " + NumToString(nibbles) +
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" hex digits");
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auto val = StringToInt(cursor_, 16);
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cursor_ += nibbles;
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return val;
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}
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void Parser::Next() {
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doc_comment_.clear();
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bool seen_newline = false;
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for (;;) {
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char c = *cursor_++;
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token_ = c;
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switch (c) {
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case '\0': cursor_--; token_ = kTokenEof; return;
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case ' ': case '\r': case '\t': break;
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case '\n': line_++; seen_newline = true; break;
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case '{': case '}': case '(': case ')': case '[': case ']': return;
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case ',': case ':': case ';': case '=': return;
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case '.':
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if(!isdigit(*cursor_)) return;
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Error("floating point constant can\'t start with \".\"");
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break;
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case '\"':
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attribute_ = "";
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while (*cursor_ != '\"') {
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if (*cursor_ < ' ' && *cursor_ >= 0)
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Error("illegal character in string constant");
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if (*cursor_ == '\\') {
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cursor_++;
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switch (*cursor_) {
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case 'n': attribute_ += '\n'; cursor_++; break;
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case 't': attribute_ += '\t'; cursor_++; break;
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case 'r': attribute_ += '\r'; cursor_++; break;
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case 'b': attribute_ += '\b'; cursor_++; break;
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case 'f': attribute_ += '\f'; cursor_++; break;
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case '\"': attribute_ += '\"'; cursor_++; break;
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case '\\': attribute_ += '\\'; cursor_++; break;
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case '/': attribute_ += '/'; cursor_++; break;
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case 'x': { // Not in the JSON standard
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cursor_++;
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attribute_ += static_cast<char>(ParseHexNum(2));
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break;
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}
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case 'u': {
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cursor_++;
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ToUTF8(static_cast<int>(ParseHexNum(4)), &attribute_);
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break;
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}
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default: Error("unknown escape code in string constant"); break;
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}
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} else { // printable chars + UTF-8 bytes
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attribute_ += *cursor_++;
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}
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}
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cursor_++;
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token_ = kTokenStringConstant;
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return;
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case '/':
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if (*cursor_ == '/') {
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const char *start = ++cursor_;
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while (*cursor_ && *cursor_ != '\n') cursor_++;
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if (*start == '/') { // documentation comment
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if (!seen_newline)
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Error("a documentation comment should be on a line on its own");
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// todo: do we want to support multiline comments instead?
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doc_comment_ += std::string(start + 1, cursor_);
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}
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break;
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}
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// fall thru
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default:
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if (isalpha(static_cast<unsigned char>(c))) {
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// Collect all chars of an identifier:
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const char *start = cursor_ - 1;
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while (isalnum(static_cast<unsigned char>(*cursor_)) ||
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*cursor_ == '_')
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cursor_++;
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attribute_.clear();
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attribute_.append(start, cursor_);
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// First, see if it is a type keyword from the table of types:
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#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) \
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if (attribute_ == IDLTYPE) { \
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token_ = kToken ## ENUM; \
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return; \
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}
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FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
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#undef FLATBUFFERS_TD
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// If it's a boolean constant keyword, turn those into integers,
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// which simplifies our logic downstream.
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if (attribute_ == "true" || attribute_ == "false") {
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attribute_ = NumToString(attribute_ == "true");
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token_ = kTokenIntegerConstant;
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return;
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}
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// Check for declaration keywords:
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if (attribute_ == "table") { token_ = kTokenTable; return; }
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if (attribute_ == "struct") { token_ = kTokenStruct; return; }
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if (attribute_ == "enum") { token_ = kTokenEnum; return; }
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if (attribute_ == "union") { token_ = kTokenUnion; return; }
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if (attribute_ == "namespace") { token_ = kTokenNameSpace; return; }
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if (attribute_ == "root_type") { token_ = kTokenRootType; return; }
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if (attribute_ == "include") { token_ = kTokenInclude; return; }
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if (attribute_ == "file_identifier") {
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token_ = kTokenFileIdentifier;
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return;
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}
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if (attribute_ == "file_extension") {
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token_ = kTokenFileExtension;
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return;
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}
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// If not, it is a user-defined identifier:
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token_ = kTokenIdentifier;
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return;
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} else if (isdigit(static_cast<unsigned char>(c)) || c == '-') {
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const char *start = cursor_ - 1;
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while (isdigit(static_cast<unsigned char>(*cursor_))) cursor_++;
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if (*cursor_ == '.') {
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cursor_++;
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while (isdigit(static_cast<unsigned char>(*cursor_))) cursor_++;
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// See if this float has a scientific notation suffix. Both JSON
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// and C++ (through strtod() we use) have the same format:
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if (*cursor_ == 'e' || *cursor_ == 'E') {
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cursor_++;
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if (*cursor_ == '+' || *cursor_ == '-') cursor_++;
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while (isdigit(static_cast<unsigned char>(*cursor_))) cursor_++;
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}
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token_ = kTokenFloatConstant;
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} else {
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token_ = kTokenIntegerConstant;
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}
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attribute_.clear();
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attribute_.append(start, cursor_);
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return;
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}
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std::string ch;
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ch = c;
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if (c < ' ' || c > '~') ch = "code: " + NumToString(c);
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Error("illegal character: " + ch);
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break;
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}
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}
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}
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// Check if a given token is next, if so, consume it as well.
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bool Parser::IsNext(int t) {
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bool isnext = t == token_;
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if (isnext) Next();
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return isnext;
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}
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// Expect a given token to be next, consume it, or error if not present.
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void Parser::Expect(int t) {
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if (t != token_) {
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Error("expecting: " + TokenToString(t) + " instead got: " +
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TokenToString(token_));
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}
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Next();
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}
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// Parse any IDL type.
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void Parser::ParseType(Type &type) {
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if (token_ >= kTokenBOOL && token_ <= kTokenSTRING) {
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type.base_type = static_cast<BaseType>(token_ - kTokenNONE);
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} else {
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if (token_ == kTokenIdentifier) {
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auto enum_def = enums_.Lookup(attribute_);
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if (enum_def) {
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type = enum_def->underlying_type;
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if (enum_def->is_union) type.base_type = BASE_TYPE_UNION;
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} else {
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type.base_type = BASE_TYPE_STRUCT;
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type.struct_def = LookupCreateStruct(attribute_);
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}
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} else if (token_ == '[') {
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Next();
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Type subtype;
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ParseType(subtype);
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if (subtype.base_type == BASE_TYPE_VECTOR) {
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// We could support this, but it will complicate things, and it's
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// easier to work around with a struct around the inner vector.
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Error("nested vector types not supported (wrap in table first).");
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}
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if (subtype.base_type == BASE_TYPE_UNION) {
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// We could support this if we stored a struct of 2 elements per
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// union element.
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Error("vector of union types not supported (wrap in table first).");
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}
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type = Type(BASE_TYPE_VECTOR, subtype.struct_def, subtype.enum_def);
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type.element = subtype.base_type;
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Expect(']');
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return;
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} else {
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Error("illegal type syntax");
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}
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}
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Next();
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}
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FieldDef &Parser::AddField(StructDef &struct_def,
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const std::string &name,
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const Type &type) {
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auto &field = *new FieldDef();
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field.value.offset =
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FieldIndexToOffset(static_cast<voffset_t>(struct_def.fields.vec.size()));
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field.name = name;
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field.value.type = type;
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if (struct_def.fixed) { // statically compute the field offset
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auto size = InlineSize(type);
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auto alignment = InlineAlignment(type);
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// structs_ need to have a predictable format, so we need to align to
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// the largest scalar
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struct_def.minalign = std::max(struct_def.minalign, alignment);
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struct_def.PadLastField(alignment);
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field.value.offset = static_cast<voffset_t>(struct_def.bytesize);
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struct_def.bytesize += size;
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}
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if (struct_def.fields.Add(name, &field))
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Error("field already exists: " + name);
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return field;
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}
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void Parser::ParseField(StructDef &struct_def) {
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std::string name = attribute_;
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std::string dc = doc_comment_;
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Expect(kTokenIdentifier);
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Expect(':');
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Type type;
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ParseType(type);
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if (struct_def.fixed && !IsScalar(type.base_type) && !IsStruct(type))
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Error("structs_ may contain only scalar or struct fields");
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FieldDef *typefield = nullptr;
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if (type.base_type == BASE_TYPE_UNION) {
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// For union fields, add a second auto-generated field to hold the type,
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// with _type appended as the name.
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typefield = &AddField(struct_def, name + "_type",
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type.enum_def->underlying_type);
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}
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auto &field = AddField(struct_def, name, type);
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if (token_ == '=') {
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Next();
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ParseSingleValue(field.value);
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}
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field.doc_comment = dc;
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ParseMetaData(field);
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field.deprecated = field.attributes.Lookup("deprecated") != nullptr;
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if (field.deprecated && struct_def.fixed)
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Error("can't deprecate fields in a struct");
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auto nested = field.attributes.Lookup("nested_flatbuffer");
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if (nested) {
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if (nested->type.base_type != BASE_TYPE_STRING)
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Error("nested_flatbuffer attribute must be a string (the root type)");
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if (field.value.type.base_type != BASE_TYPE_VECTOR ||
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field.value.type.element != BASE_TYPE_UCHAR)
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Error("nested_flatbuffer attribute may only apply to a vector of ubyte");
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// This will cause an error if the root type of the nested flatbuffer
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// wasn't defined elsewhere.
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LookupCreateStruct(nested->constant);
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}
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if (typefield) {
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// If this field is a union, and it has a manually assigned id,
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// the automatically added type field should have an id as well (of N - 1).
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auto attr = field.attributes.Lookup("id");
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if (attr) {
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auto id = atoi(attr->constant.c_str());
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auto val = new Value();
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val->type = attr->type;
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val->constant = NumToString(id - 1);
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typefield->attributes.Add("id", val);
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}
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}
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Expect(';');
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}
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void Parser::ParseAnyValue(Value &val, FieldDef *field) {
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switch (val.type.base_type) {
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case BASE_TYPE_UNION: {
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assert(field);
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if (!field_stack_.size() ||
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field_stack_.back().second->value.type.base_type != BASE_TYPE_UTYPE)
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Error("missing type field before this union value: " + field->name);
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auto enum_idx = atot<unsigned char>(
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field_stack_.back().first.constant.c_str());
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auto enum_val = val.type.enum_def->ReverseLookup(enum_idx);
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if (!enum_val) Error("illegal type id for: " + field->name);
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val.constant = NumToString(ParseTable(*enum_val->struct_def));
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break;
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}
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case BASE_TYPE_STRUCT:
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val.constant = NumToString(ParseTable(*val.type.struct_def));
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break;
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case BASE_TYPE_STRING: {
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auto s = attribute_;
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Expect(kTokenStringConstant);
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val.constant = NumToString(builder_.CreateString(s).o);
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break;
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}
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case BASE_TYPE_VECTOR: {
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Expect('[');
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val.constant = NumToString(ParseVector(val.type.VectorType()));
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break;
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}
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default:
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ParseSingleValue(val);
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break;
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}
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}
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void Parser::SerializeStruct(const StructDef &struct_def, const Value &val) {
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auto off = atot<uoffset_t>(val.constant.c_str());
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assert(struct_stack_.size() - off == struct_def.bytesize);
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builder_.Align(struct_def.minalign);
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builder_.PushBytes(&struct_stack_[off], struct_def.bytesize);
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struct_stack_.resize(struct_stack_.size() - struct_def.bytesize);
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builder_.AddStructOffset(val.offset, builder_.GetSize());
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}
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uoffset_t Parser::ParseTable(const StructDef &struct_def) {
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Expect('{');
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size_t fieldn = 0;
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if (!IsNext('}')) for (;;) {
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std::string name = attribute_;
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if (!IsNext(kTokenStringConstant)) Expect(kTokenIdentifier);
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auto field = struct_def.fields.Lookup(name);
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if (!field) Error("unknown field: " + name);
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if (struct_def.fixed && (fieldn >= struct_def.fields.vec.size()
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|| struct_def.fields.vec[fieldn] != field)) {
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Error("struct field appearing out of order: " + name);
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}
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Expect(':');
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Value val = field->value;
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ParseAnyValue(val, field);
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field_stack_.push_back(std::make_pair(val, field));
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fieldn++;
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if (IsNext('}')) break;
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Expect(',');
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}
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if (struct_def.fixed && fieldn != struct_def.fields.vec.size())
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Error("incomplete struct initialization: " + struct_def.name);
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auto start = struct_def.fixed
|
|
? builder_.StartStruct(struct_def.minalign)
|
|
: builder_.StartTable();
|
|
|
|
for (size_t size = struct_def.sortbysize ? sizeof(largest_scalar_t) : 1;
|
|
size;
|
|
size /= 2) {
|
|
// Go through elements in reverse, since we're building the data backwards.
|
|
for (auto it = field_stack_.rbegin();
|
|
it != field_stack_.rbegin() + fieldn; ++it) {
|
|
auto &value = it->first;
|
|
auto field = it->second;
|
|
if (!struct_def.sortbysize || size == SizeOf(value.type.base_type)) {
|
|
switch (value.type.base_type) {
|
|
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) \
|
|
case BASE_TYPE_ ## ENUM: \
|
|
builder_.Pad(field->padding); \
|
|
if (struct_def.fixed) { \
|
|
builder_.PushElement(atot<CTYPE>(value.constant.c_str())); \
|
|
} else { \
|
|
builder_.AddElement(value.offset, \
|
|
atot<CTYPE>( value.constant.c_str()), \
|
|
atot<CTYPE>(field->value.constant.c_str())); \
|
|
} \
|
|
break;
|
|
FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
|
|
#undef FLATBUFFERS_TD
|
|
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) \
|
|
case BASE_TYPE_ ## ENUM: \
|
|
builder_.Pad(field->padding); \
|
|
if (IsStruct(field->value.type)) { \
|
|
SerializeStruct(*field->value.type.struct_def, value); \
|
|
} else { \
|
|
builder_.AddOffset(value.offset, \
|
|
atot<CTYPE>(value.constant.c_str())); \
|
|
} \
|
|
break;
|
|
FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD);
|
|
#undef FLATBUFFERS_TD
|
|
}
|
|
}
|
|
}
|
|
}
|
|
for (size_t i = 0; i < fieldn; i++) field_stack_.pop_back();
|
|
|
|
if (struct_def.fixed) {
|
|
builder_.ClearOffsets();
|
|
builder_.EndStruct();
|
|
// Temporarily store this struct in a side buffer, since this data has to
|
|
// be stored in-line later in the parent object.
|
|
auto off = struct_stack_.size();
|
|
struct_stack_.insert(struct_stack_.end(),
|
|
builder_.GetBufferPointer(),
|
|
builder_.GetBufferPointer() + struct_def.bytesize);
|
|
builder_.PopBytes(struct_def.bytesize);
|
|
return static_cast<uoffset_t>(off);
|
|
} else {
|
|
return builder_.EndTable(
|
|
start,
|
|
static_cast<voffset_t>(struct_def.fields.vec.size()));
|
|
}
|
|
}
|
|
|
|
uoffset_t Parser::ParseVector(const Type &type) {
|
|
int count = 0;
|
|
if (token_ != ']') for (;;) {
|
|
Value val;
|
|
val.type = type;
|
|
ParseAnyValue(val, NULL);
|
|
field_stack_.push_back(std::make_pair(val, nullptr));
|
|
count++;
|
|
if (token_ == ']') break;
|
|
Expect(',');
|
|
}
|
|
Next();
|
|
|
|
builder_.StartVector(count * InlineSize(type) / InlineAlignment(type),
|
|
InlineAlignment(type));
|
|
for (int i = 0; i < count; i++) {
|
|
// start at the back, since we're building the data backwards.
|
|
auto &val = field_stack_.back().first;
|
|
switch (val.type.base_type) {
|
|
#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE) \
|
|
case BASE_TYPE_ ## ENUM: \
|
|
if (IsStruct(val.type)) SerializeStruct(*val.type.struct_def, val); \
|
|
else builder_.PushElement(atot<CTYPE>(val.constant.c_str())); \
|
|
break;
|
|
FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
|
|
#undef FLATBUFFERS_TD
|
|
}
|
|
field_stack_.pop_back();
|
|
}
|
|
|
|
builder_.ClearOffsets();
|
|
return builder_.EndVector(count);
|
|
}
|
|
|
|
void Parser::ParseMetaData(Definition &def) {
|
|
if (IsNext('(')) {
|
|
for (;;) {
|
|
auto name = attribute_;
|
|
Expect(kTokenIdentifier);
|
|
auto e = new Value();
|
|
def.attributes.Add(name, e);
|
|
if (IsNext(':')) {
|
|
ParseSingleValue(*e);
|
|
}
|
|
if (IsNext(')')) break;
|
|
Expect(',');
|
|
}
|
|
}
|
|
}
|
|
|
|
bool Parser::TryTypedValue(int dtoken,
|
|
bool check,
|
|
Value &e,
|
|
BaseType req) {
|
|
bool match = dtoken == token_;
|
|
if (match) {
|
|
e.constant = attribute_;
|
|
if (!check) {
|
|
if (e.type.base_type == BASE_TYPE_NONE) {
|
|
e.type.base_type = req;
|
|
} else {
|
|
Error(std::string("type mismatch: expecting: ") +
|
|
kTypeNames[e.type.base_type] +
|
|
", found: " +
|
|
kTypeNames[req]);
|
|
}
|
|
}
|
|
Next();
|
|
}
|
|
return match;
|
|
}
|
|
|
|
int64_t Parser::ParseIntegerFromString(Type &type) {
|
|
int64_t result = 0;
|
|
// Parse one or more enum identifiers, separated by spaces.
|
|
const char *next = attribute_.c_str();
|
|
do {
|
|
const char *divider = strchr(next, ' ');
|
|
std::string word;
|
|
if (divider) {
|
|
word = std::string(next, divider);
|
|
next = divider + strspn(divider, " ");
|
|
} else {
|
|
word = next;
|
|
next += word.length();
|
|
}
|
|
if (type.enum_def) { // The field has an enum type
|
|
auto enum_val = type.enum_def->vals.Lookup(word);
|
|
if (!enum_val)
|
|
Error("unknown enum value: " + word +
|
|
", for enum: " + type.enum_def->name);
|
|
result |= enum_val->value;
|
|
} else { // No enum type, probably integral field.
|
|
if (!IsInteger(type.base_type))
|
|
Error("not a valid value for this field: " + word);
|
|
// TODO: could check if its a valid number constant here.
|
|
const char *dot = strchr(word.c_str(), '.');
|
|
if (!dot) Error("enum values need to be qualified by an enum type");
|
|
std::string enum_def_str(word.c_str(), dot);
|
|
std::string enum_val_str(dot + 1, word.c_str() + word.length());
|
|
auto enum_def = enums_.Lookup(enum_def_str);
|
|
if (!enum_def) Error("unknown enum: " + enum_def_str);
|
|
auto enum_val = enum_def->vals.Lookup(enum_val_str);
|
|
if (!enum_val) Error("unknown enum value: " + enum_val_str);
|
|
result |= enum_val->value;
|
|
}
|
|
} while(*next);
|
|
return result;
|
|
}
|
|
|
|
void Parser::ParseSingleValue(Value &e) {
|
|
// First check if this could be a string/identifier enum value:
|
|
if (e.type.base_type != BASE_TYPE_STRING &&
|
|
e.type.base_type != BASE_TYPE_NONE &&
|
|
(token_ == kTokenIdentifier || token_ == kTokenStringConstant)) {
|
|
e.constant = NumToString(ParseIntegerFromString(e.type));
|
|
Next();
|
|
} else if (TryTypedValue(kTokenIntegerConstant,
|
|
IsScalar(e.type.base_type),
|
|
e,
|
|
BASE_TYPE_INT) ||
|
|
TryTypedValue(kTokenFloatConstant,
|
|
IsFloat(e.type.base_type),
|
|
e,
|
|
BASE_TYPE_FLOAT) ||
|
|
TryTypedValue(kTokenStringConstant,
|
|
e.type.base_type == BASE_TYPE_STRING,
|
|
e,
|
|
BASE_TYPE_STRING)) {
|
|
} else {
|
|
Error("cannot parse value starting with: " + TokenToString(token_));
|
|
}
|
|
}
|
|
|
|
StructDef *Parser::LookupCreateStruct(const std::string &name) {
|
|
auto struct_def = structs_.Lookup(name);
|
|
if (!struct_def) {
|
|
// Rather than failing, we create a "pre declared" StructDef, due to
|
|
// circular references, and check for errors at the end of parsing.
|
|
struct_def = new StructDef();
|
|
structs_.Add(name, struct_def);
|
|
struct_def->name = name;
|
|
struct_def->predecl = true;
|
|
struct_def->defined_namespace = namespaces_.back();
|
|
}
|
|
return struct_def;
|
|
}
|
|
|
|
void Parser::ParseEnum(bool is_union) {
|
|
std::string dc = doc_comment_;
|
|
Next();
|
|
std::string name = attribute_;
|
|
Expect(kTokenIdentifier);
|
|
auto &enum_def = *new EnumDef();
|
|
enum_def.name = name;
|
|
enum_def.doc_comment = dc;
|
|
enum_def.is_union = is_union;
|
|
if (enums_.Add(name, &enum_def)) Error("enum already exists: " + name);
|
|
if (is_union) {
|
|
enum_def.underlying_type.base_type = BASE_TYPE_UTYPE;
|
|
enum_def.underlying_type.enum_def = &enum_def;
|
|
} else {
|
|
// Give specialized error message, since this type spec used to
|
|
// be optional in the first FlatBuffers release.
|
|
if (!IsNext(':')) Error("must specify the underlying integer type for this"
|
|
" enum (e.g. \': short\', which was the default).");
|
|
// Specify the integer type underlying this enum.
|
|
ParseType(enum_def.underlying_type);
|
|
if (!IsInteger(enum_def.underlying_type.base_type))
|
|
Error("underlying enum type must be integral");
|
|
// Make this type refer back to the enum it was derived from.
|
|
enum_def.underlying_type.enum_def = &enum_def;
|
|
}
|
|
ParseMetaData(enum_def);
|
|
Expect('{');
|
|
if (is_union) enum_def.vals.Add("NONE", new EnumVal("NONE", 0));
|
|
do {
|
|
std::string name = attribute_;
|
|
std::string dc = doc_comment_;
|
|
Expect(kTokenIdentifier);
|
|
auto prevsize = enum_def.vals.vec.size();
|
|
auto value = enum_def.vals.vec.size()
|
|
? enum_def.vals.vec.back()->value + 1
|
|
: 0;
|
|
auto &ev = *new EnumVal(name, value);
|
|
if (enum_def.vals.Add(name, &ev))
|
|
Error("enum value already exists: " + name);
|
|
ev.doc_comment = dc;
|
|
if (is_union) {
|
|
ev.struct_def = LookupCreateStruct(name);
|
|
}
|
|
if (IsNext('=')) {
|
|
ev.value = atoi(attribute_.c_str());
|
|
Expect(kTokenIntegerConstant);
|
|
if (prevsize && enum_def.vals.vec[prevsize - 1]->value >= ev.value)
|
|
Error("enum values must be specified in ascending order");
|
|
}
|
|
} while (IsNext(','));
|
|
Expect('}');
|
|
if (enum_def.attributes.Lookup("bit_flags")) {
|
|
for (auto it = enum_def.vals.vec.begin(); it != enum_def.vals.vec.end();
|
|
++it) {
|
|
if (static_cast<size_t>((*it)->value) >=
|
|
SizeOf(enum_def.underlying_type.base_type) * 8)
|
|
Error("bit flag out of range of underlying integral type");
|
|
(*it)->value = 1LL << (*it)->value;
|
|
}
|
|
}
|
|
}
|
|
|
|
void Parser::ParseDecl() {
|
|
std::string dc = doc_comment_;
|
|
bool fixed = IsNext(kTokenStruct);
|
|
if (!fixed) Expect(kTokenTable);
|
|
std::string name = attribute_;
|
|
Expect(kTokenIdentifier);
|
|
auto &struct_def = *LookupCreateStruct(name);
|
|
if (!struct_def.predecl) Error("datatype already exists: " + name);
|
|
struct_def.predecl = false;
|
|
struct_def.name = name;
|
|
struct_def.doc_comment = dc;
|
|
struct_def.fixed = fixed;
|
|
// Move this struct to the back of the vector just in case it was predeclared,
|
|
// to preserve declartion order.
|
|
remove(structs_.vec.begin(), structs_.vec.end(), &struct_def);
|
|
structs_.vec.back() = &struct_def;
|
|
ParseMetaData(struct_def);
|
|
struct_def.sortbysize =
|
|
struct_def.attributes.Lookup("original_order") == nullptr && !fixed;
|
|
Expect('{');
|
|
while (token_ != '}') ParseField(struct_def);
|
|
auto force_align = struct_def.attributes.Lookup("force_align");
|
|
if (fixed && force_align) {
|
|
auto align = static_cast<size_t>(atoi(force_align->constant.c_str()));
|
|
if (force_align->type.base_type != BASE_TYPE_INT ||
|
|
align < struct_def.minalign ||
|
|
align > 256 ||
|
|
align & (align - 1))
|
|
Error("force_align must be a power of two integer ranging from the"
|
|
"struct\'s natural alignment to 256");
|
|
struct_def.minalign = align;
|
|
}
|
|
struct_def.PadLastField(struct_def.minalign);
|
|
// Check if this is a table that has manual id assignments
|
|
auto &fields = struct_def.fields.vec;
|
|
if (!struct_def.fixed && fields.size()) {
|
|
size_t num_id_fields = 0;
|
|
for (auto it = fields.begin(); it != fields.end(); ++it) {
|
|
if ((*it)->attributes.Lookup("id")) num_id_fields++;
|
|
}
|
|
// If any fields have ids..
|
|
if (num_id_fields) {
|
|
// Then all fields must have them.
|
|
if (num_id_fields != fields.size())
|
|
Error("either all fields or no fields must have an 'id' attribute");
|
|
// Simply sort by id, then the fields are the same as if no ids had
|
|
// been specified.
|
|
std::sort(fields.begin(), fields.end(),
|
|
[](const FieldDef *a, const FieldDef *b) -> bool {
|
|
auto a_id = atoi(a->attributes.Lookup("id")->constant.c_str());
|
|
auto b_id = atoi(b->attributes.Lookup("id")->constant.c_str());
|
|
return a_id < b_id;
|
|
});
|
|
// Verify we have a contiguous set, and reassign vtable offsets.
|
|
for (int i = 0; i < static_cast<int>(fields.size()); i++) {
|
|
if (i != atoi(fields[i]->attributes.Lookup("id")->constant.c_str()))
|
|
Error("field id\'s must be consecutive from 0, id " +
|
|
NumToString(i) + " missing or set twice");
|
|
fields[i]->value.offset = FieldIndexToOffset(static_cast<voffset_t>(i));
|
|
}
|
|
}
|
|
}
|
|
// Check that no identifiers clash with auto generated fields.
|
|
// This is not an ideal situation, but should occur very infrequently,
|
|
// and allows us to keep using very readable names for type & length fields
|
|
// without inducing compile errors.
|
|
auto CheckClash = [&fields, &struct_def](const char *suffix,
|
|
BaseType basetype) {
|
|
auto len = strlen(suffix);
|
|
for (auto it = fields.begin(); it != fields.end(); ++it) {
|
|
auto &name = (*it)->name;
|
|
if (name.length() > len &&
|
|
name.compare(name.length() - len, len, suffix) == 0 &&
|
|
(*it)->value.type.base_type != BASE_TYPE_UTYPE) {
|
|
auto field = struct_def.fields.Lookup(
|
|
name.substr(0, name.length() - len));
|
|
if (field && field->value.type.base_type == basetype)
|
|
Error("Field " + name +
|
|
" would clash with generated functions for field " +
|
|
field->name);
|
|
}
|
|
}
|
|
};
|
|
CheckClash("_type", BASE_TYPE_UNION);
|
|
CheckClash("Type", BASE_TYPE_UNION);
|
|
CheckClash("_length", BASE_TYPE_VECTOR);
|
|
CheckClash("Length", BASE_TYPE_VECTOR);
|
|
Expect('}');
|
|
}
|
|
|
|
bool Parser::SetRootType(const char *name) {
|
|
root_struct_def = structs_.Lookup(name);
|
|
return root_struct_def != nullptr;
|
|
}
|
|
|
|
void Parser::MarkGenerated() {
|
|
// Since the Parser object retains definitions across files, we must
|
|
// ensure we only output code for definitions once, in the file they are first
|
|
// declared. This function marks all existing definitions as having already
|
|
// been generated.
|
|
for (auto it = enums_.vec.begin();
|
|
it != enums_.vec.end(); ++it) {
|
|
(*it)->generated = true;
|
|
}
|
|
for (auto it = structs_.vec.begin();
|
|
it != structs_.vec.end(); ++it) {
|
|
(*it)->generated = true;
|
|
}
|
|
}
|
|
|
|
bool Parser::Parse(const char *source, const char *filepath) {
|
|
included_files_[filepath] = true;
|
|
// This is the starting point to reset to if we interrupted our parsing
|
|
// to deal with an include:
|
|
restart_parse_after_include:
|
|
source_ = cursor_ = source;
|
|
line_ = 1;
|
|
error_.clear();
|
|
builder_.Clear();
|
|
try {
|
|
Next();
|
|
// Includes must come first:
|
|
while (IsNext(kTokenInclude)) {
|
|
auto name = attribute_;
|
|
Expect(kTokenStringConstant);
|
|
auto path = StripFileName(filepath);
|
|
if (path.length()) name = path + kPathSeparator + name;
|
|
if (included_files_.find(name) == included_files_.end()) {
|
|
// We found an include file that we have not parsed yet.
|
|
// Load it and parse it.
|
|
std::string contents;
|
|
if (!LoadFile(name.c_str(), true, &contents))
|
|
Error("unable to load include file: " + name);
|
|
Parse(contents.c_str(), name.c_str());
|
|
// Any errors, we're done.
|
|
if (error_.length()) return false;
|
|
// We do not want to output code for any included files:
|
|
MarkGenerated();
|
|
// This is the easiest way to continue this file after an include:
|
|
// instead of saving and restoring all the state, we simply start the
|
|
// file anew. This will cause it to encounter the same include statement
|
|
// again, but this time it will skip it, because it was entered into
|
|
// included_files_.
|
|
goto restart_parse_after_include;
|
|
}
|
|
Expect(';');
|
|
}
|
|
// Now parse all other kinds of declarations:
|
|
while (token_ != kTokenEof) {
|
|
if (token_ == kTokenNameSpace) {
|
|
Next();
|
|
auto ns = new Namespace();
|
|
namespaces_.push_back(ns);
|
|
for (;;) {
|
|
ns->components.push_back(attribute_);
|
|
Expect(kTokenIdentifier);
|
|
if (!IsNext('.')) break;
|
|
}
|
|
Expect(';');
|
|
} else if (token_ == '{') {
|
|
if (!root_struct_def) Error("no root type set to parse json with");
|
|
if (builder_.GetSize()) {
|
|
Error("cannot have more than one json object in a file");
|
|
}
|
|
builder_.Finish(Offset<Table>(ParseTable(*root_struct_def)));
|
|
} else if (token_ == kTokenEnum) {
|
|
ParseEnum(false);
|
|
} else if (token_ == kTokenUnion) {
|
|
ParseEnum(true);
|
|
} else if (token_ == kTokenRootType) {
|
|
Next();
|
|
auto root_type = attribute_;
|
|
Expect(kTokenIdentifier);
|
|
if (!SetRootType(root_type.c_str()))
|
|
Error("unknown root type: " + root_type);
|
|
if (root_struct_def->fixed)
|
|
Error("root type must be a table");
|
|
Expect(';');
|
|
} else if (token_ == kTokenFileIdentifier) {
|
|
Next();
|
|
file_identifier_ = attribute_;
|
|
Expect(kTokenStringConstant);
|
|
if (file_identifier_.length() !=
|
|
FlatBufferBuilder::kFileIdentifierLength)
|
|
Error("file_identifier must be exactly " +
|
|
NumToString(FlatBufferBuilder::kFileIdentifierLength) +
|
|
" characters");
|
|
Expect(';');
|
|
} else if (token_ == kTokenFileExtension) {
|
|
Next();
|
|
file_extension_ = attribute_;
|
|
Expect(kTokenStringConstant);
|
|
Expect(';');
|
|
} else if(token_ == kTokenInclude) {
|
|
Error("includes must come before declarations");
|
|
} else {
|
|
ParseDecl();
|
|
}
|
|
}
|
|
for (auto it = structs_.vec.begin(); it != structs_.vec.end(); ++it) {
|
|
if ((*it)->predecl)
|
|
Error("type referenced but not defined: " + (*it)->name);
|
|
}
|
|
for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
|
|
auto &enum_def = **it;
|
|
if (enum_def.is_union) {
|
|
for (auto it = enum_def.vals.vec.begin();
|
|
it != enum_def.vals.vec.end();
|
|
++it) {
|
|
auto &val = **it;
|
|
if (val.struct_def && val.struct_def->fixed)
|
|
Error("only tables can be union elements: " + val.name);
|
|
}
|
|
}
|
|
}
|
|
} catch (const std::string &msg) {
|
|
error_ = "line " + NumToString(line_) + ": " + msg;
|
|
return false;
|
|
}
|
|
assert(!struct_stack_.size());
|
|
return true;
|
|
}
|
|
|
|
} // namespace flatbuffers
|