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Diffstat (limited to 'src/core/parser/stack/Handler.hpp')
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diff --git a/src/core/parser/stack/Handler.hpp b/src/core/parser/stack/Handler.hpp new file mode 100644 index 0000000..7cda7a4 --- /dev/null +++ b/src/core/parser/stack/Handler.hpp @@ -0,0 +1,421 @@ +/* + Ousía + Copyright (C) 2014 Benjamin Paaßen, Andreas Stöckel + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef _OUSIA_PARSER_STACK_HANDLER_HPP_ +#define _OUSIA_PARSER_STACK_HANDLER_HPP_ + +#include <string> + +#include <core/common/Location.hpp> +#include <core/common/Variant.hpp> +#include <core/common/Whitespace.hpp> + +namespace ousia { + +// Forward declarations +class ParserScope; +class ParserContext; +class Logger; + +namespace parser_stack { + +// More forward declarations +class Callbacks; +class State; + +/** + * Class collecting all the data that is being passed to a Handler + * instance. + */ +class HandlerData { +public: + /** + * Reference to the ParserContext instance that should be used to resolve + * references to nodes in the Graph. + */ + ParserContext &ctx; + + /** + * Reference at an instance of the Callbacks class, used for + * modifying the behaviour of the parser (like registering tokens, setting + * the data type or changing the whitespace handling mode). + */ + // Callbacks &callbacks; + + /** + * Contains the name of the command that is being handled. + */ + std::string name; + + /** + * Contains the current state of the state machine. + */ + const State &state; + + /** + * Current source code location. + */ + SourceLocation location; + + /** + * Constructor of the HandlerData class. + * + * @param ctx is the parser context the handler should be executed in. + * @param callbacks is an instance of Callbacks used to notify + * the parser about certain state changes. + * @param name is the name of the string. + * @param state is the state this handler was called for. + * @param location is the location at which the handler is created. + */ + HandlerData(ParserContext &ctx, + /*Callbacks &callbacks,*/ const std::string &name, + const State &state, const SourceLocation &location); +}; + +/** + * The Handler class provides a context for handling a generic stack element. + * It has to beoverridden and registered in the StateStack class to form + * handlers for concrete XML tags. + */ +class Handler { +private: + /** + * Structure containing the internal handler data. + */ + const HandlerData handlerData; + + /** + * Reference at the current logger. If not nullptr, this will override the + * logger from the ParserContext specified in the handlerData. + */ + Logger *internalLogger; + +protected: + /** + * Constructor of the Handler class. + * + * @param data is a structure containing all data being passed to the + * handler. + */ + Handler(const HandlerData &handlerData); + + /** + * Returns a reference at the ParserContext. + * + * @return a reference at the ParserContext. + */ + ParserContext &context(); + + /** + * Returns a reference at the ParserScope instance. + * + * @return a reference at the ParserScope instance. + */ + ParserScope &scope(); + + /** + * Returns a reference at the Manager instance which manages all nodes. + * + * @return a referance at the Manager instance. + */ + Manager &manager(); + + /** + * Returns a reference at the Logger instance used for logging error + * messages. + * + * @return a reference at the Logger instance. + */ + Logger &logger(); + + /** + * Returns the location of the element in the source file, for which this + * Handler was created. + * + * @return the location of the Handler in the source file. + */ + const SourceLocation &location() const; + + /** + * Returns the command name for which the handler was created. + * + * @return a const reference at the command name. + */ + const std::string &name() const; + +public: + /** + * Virtual destructor. + */ + virtual ~Handler(); + + /** + * Calls the corresponding function in the Callbacks instance. Sets the + * whitespace mode that specifies how string data should be processed. The + * calls to this function are placed on a stack by the underlying Stack + * class. + * + * @param whitespaceMode specifies one of the three WhitespaceMode constants + * PRESERVE, TRIM or COLLAPSE. + */ + void setWhitespaceMode(WhitespaceMode whitespaceMode); + + /** + * Calls the corresponding function in the Callbacks instance. + * Registers the given token as token that should be reported to the handler + * using the "token" function. + * + * @param token is the token string that should be reported. + */ + void registerToken(const std::string &token); + + /** + * Calls the corresponding function in the Callbacks instance. + * Unregisters the given token, it will no longer be reported to the handler + * using the "token" function. + * + * @param token is the token string that should be unregistered. + */ + void unregisterToken(const std::string &token); + + /** + * Returns the command name for which the handler was created. + * + * @return a const reference at the command name. + */ + const std::string &getName() const; + + /** + * Reference at the State descriptor for which this Handler was created. + * + * @return a const reference at the constructing State descriptor. + */ + const State &getState() const; + + /** + * Sets the internal logger to the given logger instance. + * + * @param logger is the Logger instance to which the logger should be set. + */ + void setLogger(Logger &logger); + + /** + * Resets the logger instance to the logger instance provided in the + * ParserContext. + */ + void resetLogger(); + + /** + * Returns the location of the element in the source file, for which this + * Handler was created. + * + * @return the location of the Handler in the source file. + */ + const SourceLocation &getLocation() const; + + /** + * Called when the command that was specified in the constructor is + * instanciated. + * + * @param args is a map from strings to variants (argument name and value). + * @return true if the handler was successful in starting the element it + * represents, false otherwise. + */ + virtual bool start(Variant::mapType &args) = 0; + + /** + * Called before the command for which this handler is defined ends (is + * forever removed from the stack). + */ + virtual void end() = 0; + + /** + * Called when a new field starts, while the handler is active. This + * function should return true if the field is supported, false otherwise. + * No error should be logged if the field cannot be started, the caller will + * take care of that (since it is always valid to start a default field, + * even though the corresponding structure does not have a field, as long as + * no data is fed into the field). + * + * @param isDefault is set to true if the field that is being started is the + * default/tree field. The handler should set the value of this variable to + * true if the referenced field is indeed the default field. + * @param fieldIdx is the numerical index of the field. + */ + virtual bool fieldStart(bool &isDefault, size_t fieldIdx) = 0; + + /** + * Called when a previously opened field ends, while the handler is active. + * Note that a "fieldStart" and "fieldEnd" are always called alternately. + */ + virtual void fieldEnd() = 0; + + /** + * Called whenever an annotation starts while this handler is active. The + * function should return true if starting the annotation was successful, + * false otherwise. + * + * @param className is a string variant containing the name of the + * annotation class and the location of the name in the source code. + * @param args is a map from strings to variants (argument name and value). + * @return true if the mentioned annotation could be started here, false + * if an error occurred. + */ + virtual bool annotationStart(const Variant &className, + Variant::mapType &args) = 0; + + /** + * Called whenever an annotation ends while this handler is active. The + * function should return true if ending the annotation was successful, + * false otherwise. + * + * @param className is a string variant containing the name of the + * annotation class and the location of the class name in the source code. + * @param elementName is a string variant containing the name of the + * annotation class and the location of the element name in the source code. + * @return true if the mentioned annotation could be started here, false if + * an error occurred. + */ + virtual bool annotationEnd(const Variant &className, + const Variant &elementName) = 0; + + /** + * Called whenever raw data (int the form of a string) is available for the + * Handler instance. Should return true if the data could be handled, false + * otherwise. + * + * @param data is a string variant containing the character data and its + * location. + * @return true if the data could be handled, false otherwise. + */ + virtual bool data(Variant &data) = 0; +}; + +/** + * HandlerConstructor is a function pointer type used to create concrete + * instances of the Handler class. + * + * @param handlerData is the data that should be passed to the new handler + * instance. + * @return a newly created handler instance. + */ +using HandlerConstructor = Handler *(*)(const HandlerData &handlerData); + +/** + * The EmptyHandler class is used in case no element handler is specified in + * the State descriptor. It just accepts all data and does nothing. + */ +class EmptyHandler : public Handler { +protected: + using Handler::Handler; + +public: + bool start(Variant::mapType &args) override; + void end() override; + bool fieldStart(bool &isDefault, size_t fieldIdx) override; + void fieldEnd() override; + bool annotationStart(const Variant &className, + Variant::mapType &args) override; + bool annotationEnd(const Variant &className, + const Variant &elementName) override; + bool data(Variant &data) override; + + /** + * Creates an instance of the EmptyHandler class. + */ + static Handler *create(const HandlerData &handlerData); +}; + +/** + * The StaticHandler class is used to handle predifined commands which do + * neither support annotations, nor multiple fields. Child classes can decide + * whether a single data field should be used. + */ +class StaticHandler : public Handler { +protected: + using Handler::Handler; + +public: + bool start(Variant::mapType &args) override; + void end() override; + bool fieldStart(bool &isDefault, size_t fieldIdx) override; + void fieldEnd() override; + bool annotationStart(const Variant &className, + Variant::mapType &args) override; + bool annotationEnd(const Variant &className, + const Variant &elementName) override; + bool data(Variant &data) override; +}; + +/** + * The StaticFieldHandler class is used to handle predifined commands which do + * neither support annotations, nor multiple fields. Additionally, it captures a + * data entry from a single default field. + */ +class StaticFieldHandler : public StaticHandler { +private: + /** + * Set to the name of the data argument that should be used instead of the + * data field, if no data field is given. + */ + std::string argName; + + /** + * Set to true, once the "doHandle" function has been called. + */ + bool handled; + + /** + * Map containing the arguments given in the start function. + */ + Variant::mapType args; + +protected: + /** + * Constructor of the StaticFieldHandler class. + * + * @param handlerData is a structure containing the internal data that + * should be stored inside the handler. + * @param name of the data argument that -- if present -- should be used + * instead of the data field. If empty, data is not captured from the + * arguments. If both, data in the data field and the argument, are given, + * this results in an error. + */ + StaticFieldHandler(const HandlerData &handlerData, + const std::string &argName); + + /** + * Function that should be overriden in order to handle the field data and + * the other arguments. This function is not called if no data was given. + * + * @param fieldData is the captured field data. + * @param args are the arguments that were given in the "start" function. + */ + virtual void doHandle(const Variant &fieldData, + Variant::mapType &args) = 0; + +public: + bool start(Variant::mapType &args) override; + void end() override; + bool data(Variant &data) override; +}; +} +} + +#endif /* _OUSIA_PARSER_STACK_HANDLER_HPP_ */ + |