// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.
// http://code.google.com/p/protobuf/
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Author: kenton@google.com (Kenton Varda)
// Based on original Protocol Buffers design by
// Sanjay Ghemawat, Jeff Dean, and others.
//
// Implements parsing of .proto files to FileDescriptorProtos.
#ifndef GOOGLE_PROTOBUF_COMPILER_PARSER_H__
#define GOOGLE_PROTOBUF_COMPILER_PARSER_H__
#include <map>
#include <string>
#include <utility>
#include <google/protobuf/stubs/common.h>
#include <google/protobuf/descriptor.h>
#include <google/protobuf/descriptor.pb.h>
#include <google/protobuf/repeated_field.h>
#include <google/protobuf/io/tokenizer.h>
namespace google {
namespace protobuf { class Message; }
namespace protobuf {
namespace compiler {
// Defined in this file.
class Parser;
class SourceLocationTable;
// Implements parsing of protocol definitions (such as .proto files).
//
// Note that most users will be more interested in the Importer class.
// Parser is a lower-level class which simply converts a single .proto file
// to a FileDescriptorProto. It does not resolve import directives or perform
// many other kinds of validation needed to construct a complete
// FileDescriptor.
class LIBPROTOBUF_EXPORT Parser {
public:
Parser();
~Parser();
// Parse the entire input and construct a FileDescriptorProto representing
// it. Returns true if no errors occurred, false otherwise.
bool Parse(io::Tokenizer* input, FileDescriptorProto* file);
// Optional fetaures:
// Requests that locations of certain definitions be recorded to the given
// SourceLocationTable while parsing. This can be used to look up exact line
// and column numbers for errors reported by DescriptorPool during validation.
// Set to NULL (the default) to discard source location information.
void RecordSourceLocationsTo(SourceLocationTable* location_table) {
source_location_table_ = location_table;
}
// Requsets that errors be recorded to the given ErrorCollector while
// parsing. Set to NULL (the default) to discard error messages.
void RecordErrorsTo(io::ErrorCollector* error_collector) {
error_collector_ = error_collector;
}
// Returns the identifier used in the "syntax = " declaration, if one was
// seen during the last call to Parse(), or the empty string otherwise.
const string& GetSyntaxIndentifier() { return syntax_identifier_; }
// If set true, input files will be required to begin with a syntax
// identifier. Otherwise, files may omit this. If a syntax identifier
// is provided, it must be 'syntax = "proto2";' and must appear at the
// top of this file regardless of whether or not it was required.
void SetRequireSyntaxIdentifier(bool value) {
require_syntax_identifier_ = value;
}
private:
// =================================================================
// Error recovery helpers
// Consume the rest of the current statement. This consumes tokens
// until it sees one of:
// ';' Consumes the token and returns.
// '{' Consumes the brace then calls SkipRestOfBlock().
// '}' Returns without consuming.
// EOF Returns (can't consume).
// The Parser often calls SkipStatement() after encountering a syntax
// error. This allows it to go on parsing the following lines, allowing
// it to report more than just one error in the file.
void SkipStatement();
// Consume the rest of the current block, including nested blocks,
// ending after the closing '}' is encountered and consumed, or at EOF.
void SkipRestOfBlock();
// -----------------------------------------------------------------
// Single-token consuming helpers
//
// These make parsing code more readable.
// True if the current token is TYPE_END.
inline bool AtEnd();
// True if the next token matches the given text.
inline bool LookingAt(const char* text);
// True if the next token is of the given type.
inline bool LookingAtType(io::Tokenizer::TokenType token_type);
// If the next token exactly matches the text given, consume it and return
// true. Otherwise, return false without logging an error.
bool TryConsume(const char* text);
// These attempt to read some kind of token from the input. If successful,
// they return true. Otherwise they return false and add the given error
// to the error list.
// Consume a token with the exact text given.
bool Consume(const char* text, const char* error);
// Same as above, but automatically generates the error "Expected \"text\".",
// where "text" is the expected token text.
bool Consume(const char* text);
// Consume a token of type IDENTIFIER and store its text in "output".
bool ConsumeIdentifier(string* output, const char* error);
// Consume an integer and store its value in "output".
bool ConsumeInteger(int* output, const char* error);
// Consume a 64-bit integer and store its value in "output". If the value
// is greater than max_value, an error will be reported.
bool ConsumeInteger64(uint64 max_value, uint64* output, const char* error);
// Consume a number and store its value in "output". This will accept
// tokens of either INTEGER or FLOAT type.
bool ConsumeNumber(double* output, const char* error);
// Consume a string literal and store its (unescaped) value in "output".
bool ConsumeString(string* output, const char* error);
// -----------------------------------------------------------------
// Error logging helpers
// Invokes error_collector_->AddError(), if error_collector_ is not NULL.
void AddError(int line, int column, const string& error);
// Invokes error_collector_->AddError() with the line and column number
// of the current token.
void AddError(const string& error);
// Record the given line and column and associate it with this descriptor
// in the SourceLocationTable.
void RecordLocation(const Message* descriptor,
DescriptorPool::ErrorCollector::ErrorLocation location,
int line, int column);
// Record the current line and column and associate it with this descriptor
// in the SourceLocationTable.
void RecordLocation(const Message* descriptor,
DescriptorPool::ErrorCollector::ErrorLocation location);
// =================================================================
// Parsers for various language constructs
// Parses the "syntax = \"proto2\";" line at the top of the file. Returns
// false if it failed to parse or if the syntax identifier was not
// recognized.
bool ParseSyntaxIdentifier();
// These methods parse various individual bits of code. They return
// false if they completely fail to parse the construct. In this case,
// it is probably necessary to skip the rest of the statement to recover.
// However, if these methods return true, it does NOT mean that there
// were no errors; only that there were no *syntax* errors. For instance,
// if a service method is defined using proper syntax but uses a primitive
// type as its input or output, ParseMethodField() still returns true
// and only reports the error by calling AddError(). In practice, this
// makes logic much simpler for the caller.
// Parse a top-level message, enum, service, etc.
bool ParseTopLevelStatement(FileDescriptorProto* file);
// Parse various language high-level language construrcts.
bool ParseMessageDefinition(DescriptorProto* message);
bool ParseEnumDefinition(EnumDescriptorProto* enum_type);
bool ParseServiceDefinition(ServiceDescriptorProto* service);
bool ParsePackage(FileDescriptorProto* file);
bool ParseImport(string* import_filename);
bool ParseOption(Message* options);
// These methods parse the contents of a message, enum, or service type and
// add them to the given object. They consume the entire block including
// the beginning and ending brace.
bool ParseMessageBlock(DescriptorProto* message);
bool ParseEnumBlock(EnumDescriptorProto* enum_type);
bool ParseServiceBlock(ServiceDescriptorProto* service);
// Parse one statement within a message, enum, or service block, inclunding
// final semicolon.
bool ParseMessageStatement(DescriptorProto* message);
bool ParseEnumStatement(EnumDescriptorProto* message);
bool ParseServiceStatement(ServiceDescriptorProto* message);
// Parse a field of a message. If the field is a group, its type will be
// added to "messages".
bool ParseMessageField(FieldDescriptorProto* field,
RepeatedPtrField<DescriptorProto>* messages);
// Parse an "extensions" declaration.
bool ParseExtensions(DescriptorProto* message);
// Parse an "extend" declaration.
bool ParseExtend(RepeatedPtrField<FieldDescriptorProto>* extensions,
RepeatedPtrField<DescriptorProto>* messages);
// Parse a single enum value within an enum block.
bool ParseEnumConstant(EnumValueDescriptorProto* enum_value);
// Parse a single method within a service definition.
bool ParseServiceMethod(MethodDescriptorProto* method);
// Parse "required", "optional", or "repeated" and fill in "label"
// with the value.
bool ParseLabel(FieldDescriptorProto::Label* label);
// Parse a type name and fill in "type" (if it is a primitive) or
// "type_name" (if it is not) with the type parsed.
bool ParseType(FieldDescriptorProto::Type* type,
string* type_name);
// Parse a user-defined type and fill in "type_name" with the name.
// If a primitive type is named, it is treated as an error.
bool ParseUserDefinedType(string* type_name);
// Parses field options, i.e. the stuff in square brackets at the end
// of a field definition. Also parses default value.
bool ParseFieldOptions(FieldDescriptorProto* field);
// Parse the "default" option. This needs special handling because its
// type is the field's type.
bool ParseDefaultAssignment(FieldDescriptorProto* field);
// Parse a single option name/value pair, e.g. "ctype = CORD". The name
// identifies a field of the given Message, and the value of that field
// is set to the parsed value.
bool ParseOptionAssignment(Message* options);
// =================================================================
io::Tokenizer* input_;
io::ErrorCollector* error_collector_;
SourceLocationTable* source_location_table_;
bool had_errors_;
bool require_syntax_identifier_;
string syntax_identifier_;
GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Parser);
};
// A table mapping (descriptor, ErrorLocation) pairs -- as reported by
// DescriptorPool when validating descriptors -- to line and column numbers
// within the original source code.
class LIBPROTOBUF_EXPORT SourceLocationTable {
public:
SourceLocationTable();
~SourceLocationTable();
// Finds the precise location of the given error and fills in *line and
// *column with the line and column numbers. If not found, sets *line to
// -1 and *column to 0 (since line = -1 is used to mean "error has no exact
// location" in the ErrorCollector interface). Returns true if found, false
// otherwise.
bool Find(const Message* descriptor,
DescriptorPool::ErrorCollector::ErrorLocation location,
int* line, int* column) const;
// Adds a location to the table.
void Add(const Message* descriptor,
DescriptorPool::ErrorCollector::ErrorLocation location,
int line, int column);
// Clears the contents of the table.
void Clear();
private:
typedef map<
pair<const Message*, DescriptorPool::ErrorCollector::ErrorLocation>,
pair<int, int> > LocationMap;
LocationMap location_map_;
};
} // namespace compiler
} // namespace protobuf
} // namespace google
#endif // GOOGLE_PROTOBUF_COMPILER_PARSER_H__
