src/tint/writer/text_generator.h - dawn - Git at Google

 // Copyright 2020 The Tint Authors.
 //
 // 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.

 #ifndef SRC_TINT_WRITER_TEXT_GENERATOR_H_
 #define SRC_TINT_WRITER_TEXT_GENERATOR_H_

 #include <string>
 #include <unordered_map>
 #include <utility>
 #include <vector>

 #include "src/tint/diagnostic/diagnostic.h"
 #include "src/tint/program_builder.h"
 #include "src/tint/utils/string_stream.h"

 namespace tint::writer {

 /// Helper methods for generators which are creating text output
 class TextGenerator {
   public:
     /// Line holds a single line of text
     struct Line {
         /// The indentation of the line in blankspace
         uint32_t indent = 0;
         /// The content of the line, without a trailing newline character
         std::string content;
     };

     /// TextBuffer holds a list of lines of text.
     struct TextBuffer {
         // Constructor
         TextBuffer();

         // Destructor
         ~TextBuffer();

         /// IncrementIndent increases the indentation of lines that will be written
         /// to the TextBuffer
         void IncrementIndent();

         /// DecrementIndent decreases the indentation of lines that will be written
         /// to the TextBuffer
         void DecrementIndent();

         /// Appends the line to the end of the TextBuffer
         /// @param line the line to append to the TextBuffer
         void Append(const std::string& line);

         /// Inserts the line to the TextBuffer before the line with index `before`
         /// @param line the line to append to the TextBuffer
         /// @param before the zero-based index of the line to insert the text before
         /// @param indent the indentation to apply to the inserted lines
         void Insert(const std::string& line, size_t before, uint32_t indent);

         /// Appends the lines of `tb` to the end of this TextBuffer
         /// @param tb the TextBuffer to append to the end of this TextBuffer
         void Append(const TextBuffer& tb);

         /// Inserts the lines of `tb` to the TextBuffer before the line with index
         /// `before`
         /// @param tb the TextBuffer to insert into this TextBuffer
         /// @param before the zero-based index of the line to insert the text before
         /// @param indent the indentation to apply to the inserted lines
         void Insert(const TextBuffer& tb, size_t before, uint32_t indent);

         /// @returns the buffer's content as a single string
         /// @param indent additional indentation to apply to each line
         std::string String(uint32_t indent = 0) const;

         /// The current indentation of the TextBuffer. Lines appended to the
         /// TextBuffer will use this indentation.
         uint32_t current_indent = 0;

         /// The lines
         std::vector<Line> lines;
     };

     /// Constructor
     /// @param program the program used by the generator
     explicit TextGenerator(const Program* program);
     ~TextGenerator();

     /// Increment the emitter indent level
     void increment_indent() { current_buffer_->IncrementIndent(); }
     /// Decrement the emitter indent level
     void decrement_indent() { current_buffer_->DecrementIndent(); }

     /// @returns the result data
     std::string result() const { return main_buffer_.String(); }

     /// @returns the list of diagnostics raised by the generator.
     const diag::List& Diagnostics() const { return diagnostics_; }

     /// @returns the error
     std::string error() const { return diagnostics_.str(); }

     /// @return a new, unique identifier with the given prefix.
     /// @param prefix optional prefix to apply to the generated identifier. If
     /// empty "tint_symbol" will be used.
     std::string UniqueIdentifier(const std::string& prefix = "");

     /// @param s the semantic structure
     /// @returns the name of the structure, taking special care of builtin
     /// structures that start with double underscores. If the structure is a
     /// builtin, then the returned name will be a unique name without the leading
     /// underscores.
     std::string StructName(const sem::Struct* s);

     /// @param str the string
     /// @param suffix the suffix to remove
     /// @return returns str without the provided trailing suffix string. If str
     /// doesn't end with suffix, str is returned unchanged.
     std::string TrimSuffix(std::string str, const std::string& suffix);

   protected:
     /// LineWriter is a helper that acts as a string buffer, who's content is
     /// emitted to the TextBuffer as a single line on destruction.
     struct LineWriter {
       public:
         /// Constructor
         /// @param buffer the TextBuffer that the LineWriter will append its
         /// content to on destruction, at the end of the buffer.
         explicit LineWriter(TextBuffer* buffer);

         /// Move constructor
         /// @param rhs the LineWriter to move
         LineWriter(LineWriter&& rhs);
         /// Destructor
         ~LineWriter();

         /// @returns the utils::StringStream
         operator utils::StringStream&() { return os; }

         /// @param rhs the value to write to the line
         /// @returns the utils::StringStream so calls can be chained
         template <typename T>
         utils::StringStream& operator<<(T&& rhs) {
             return os << std::forward<T>(rhs);
         }

       private:
         LineWriter(const LineWriter&) = delete;
         LineWriter& operator=(const LineWriter&) = delete;

         utils::StringStream os;
         TextBuffer* buffer;
     };

     /// Helper for writing a '(' on construction and a ')' destruction.
     struct ScopedParen {
         /// Constructor
         /// @param stream the utils::StringStream that will be written to
         explicit ScopedParen(utils::StringStream& stream);
         /// Destructor
         ~ScopedParen();

       private:
         ScopedParen(ScopedParen&& rhs) = delete;
         ScopedParen(const ScopedParen&) = delete;
         ScopedParen& operator=(const ScopedParen&) = delete;
         utils::StringStream& s;
     };

     /// Helper for incrementing indentation on construction and decrementing
     /// indentation on destruction.
     struct ScopedIndent {
         /// Constructor
         /// @param buffer the TextBuffer that the ScopedIndent will indent
         explicit ScopedIndent(TextBuffer* buffer);
         /// Constructor
         /// @param generator ScopedIndent will indent the generator's
         /// `current_buffer_`
         explicit ScopedIndent(TextGenerator* generator);
         /// Destructor
         ~ScopedIndent();

       private:
         ScopedIndent(ScopedIndent&& rhs) = delete;
         ScopedIndent(const ScopedIndent&) = delete;
         ScopedIndent& operator=(const ScopedIndent&) = delete;
         TextBuffer* buffer_;
     };

     /// @returns the resolved type of the ast::Expression `expr`
     /// @param expr the expression
     const type::Type* TypeOf(const ast::Expression* expr) const { return builder_.TypeOf(expr); }

     /// @returns the resolved type of the ast::TypeDecl `type_decl`
     /// @param type_decl the type
     const type::Type* TypeOf(const ast::TypeDecl* type_decl) const {
         return builder_.TypeOf(type_decl);
     }

     /// @returns a new LineWriter, used for buffering and writing a line to
     /// the end of #current_buffer_.
     LineWriter line() { return LineWriter(current_buffer_); }

     /// @param buffer the TextBuffer to write the line to
     /// @returns a new LineWriter, used for buffering and writing a line to
     /// the end of `buffer`.
     static LineWriter line(TextBuffer* buffer) { return LineWriter(buffer); }

     /// The program
     Program const* const program_;
     /// A ProgramBuilder that thinly wraps program_
     ProgramBuilder builder_;
     /// Diagnostics generated by the generator
     diag::List diagnostics_;
     /// The buffer the TextGenerator is currently appending lines to
     TextBuffer* current_buffer_ = &main_buffer_;

   private:
     /// The primary text buffer that the generator will emit
     TextBuffer main_buffer_;
     /// Map of builtin structure to unique generated name
     std::unordered_map<const sem::Struct*, std::string> builtin_struct_names_;
 };

 }  // namespace tint::writer

 #endif  // SRC_TINT_WRITER_TEXT_GENERATOR_H_
	// Copyright 2020 The Tint Authors.
	//
	// 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.

	#ifndef SRC_TINT_WRITER_TEXT_GENERATOR_H_
	#define SRC_TINT_WRITER_TEXT_GENERATOR_H_

	#include <string>
	#include <unordered_map>
	#include <utility>
	#include <vector>

	#include "src/tint/diagnostic/diagnostic.h"
	#include "src/tint/program_builder.h"
	#include "src/tint/utils/string_stream.h"

	namespace tint::writer {

	/// Helper methods for generators which are creating text output
	class TextGenerator {
	public:
	/// Line holds a single line of text
	struct Line {
	/// The indentation of the line in blankspace
	uint32_t indent = 0;
	/// The content of the line, without a trailing newline character
	std::string content;
	};

	/// TextBuffer holds a list of lines of text.
	struct TextBuffer {
	// Constructor
	TextBuffer();

	// Destructor
	~TextBuffer();

	/// IncrementIndent increases the indentation of lines that will be written
	/// to the TextBuffer
	void IncrementIndent();

	/// DecrementIndent decreases the indentation of lines that will be written
	/// to the TextBuffer
	void DecrementIndent();

	/// Appends the line to the end of the TextBuffer
	/// @param line the line to append to the TextBuffer
	void Append(const std::string& line);

	/// Inserts the line to the TextBuffer before the line with index `before`
	/// @param line the line to append to the TextBuffer
	/// @param before the zero-based index of the line to insert the text before
	/// @param indent the indentation to apply to the inserted lines
	void Insert(const std::string& line, size_t before, uint32_t indent);

	/// Appends the lines of `tb` to the end of this TextBuffer
	/// @param tb the TextBuffer to append to the end of this TextBuffer
	void Append(const TextBuffer& tb);

	/// Inserts the lines of `tb` to the TextBuffer before the line with index
	/// `before`
	/// @param tb the TextBuffer to insert into this TextBuffer
	/// @param before the zero-based index of the line to insert the text before
	/// @param indent the indentation to apply to the inserted lines
	void Insert(const TextBuffer& tb, size_t before, uint32_t indent);

	/// @returns the buffer's content as a single string
	/// @param indent additional indentation to apply to each line
	std::string String(uint32_t indent = 0) const;

	/// The current indentation of the TextBuffer. Lines appended to the
	/// TextBuffer will use this indentation.
	uint32_t current_indent = 0;

	/// The lines
	std::vector<Line> lines;
	};

	/// Constructor
	/// @param program the program used by the generator
	explicit TextGenerator(const Program* program);
	~TextGenerator();

	/// Increment the emitter indent level
	void increment_indent() { current_buffer_->IncrementIndent(); }
	/// Decrement the emitter indent level
	void decrement_indent() { current_buffer_->DecrementIndent(); }

	/// @returns the result data
	std::string result() const { return main_buffer_.String(); }

	/// @returns the list of diagnostics raised by the generator.
	const diag::List& Diagnostics() const { return diagnostics_; }

	/// @returns the error
	std::string error() const { return diagnostics_.str(); }

	/// @return a new, unique identifier with the given prefix.
	/// @param prefix optional prefix to apply to the generated identifier. If
	/// empty "tint_symbol" will be used.
	std::string UniqueIdentifier(const std::string& prefix = "");

	/// @param s the semantic structure
	/// @returns the name of the structure, taking special care of builtin
	/// structures that start with double underscores. If the structure is a
	/// builtin, then the returned name will be a unique name without the leading
	/// underscores.
	std::string StructName(const sem::Struct* s);

	/// @param str the string
	/// @param suffix the suffix to remove
	/// @return returns str without the provided trailing suffix string. If str
	/// doesn't end with suffix, str is returned unchanged.
	std::string TrimSuffix(std::string str, const std::string& suffix);

	protected:
	/// LineWriter is a helper that acts as a string buffer, who's content is
	/// emitted to the TextBuffer as a single line on destruction.
	struct LineWriter {
	public:
	/// Constructor
	/// @param buffer the TextBuffer that the LineWriter will append its
	/// content to on destruction, at the end of the buffer.
	explicit LineWriter(TextBuffer* buffer);

	/// Move constructor
	/// @param rhs the LineWriter to move
	LineWriter(LineWriter&& rhs);
	/// Destructor
	~LineWriter();

	/// @returns the utils::StringStream
	operator utils::StringStream&() { return os; }

	/// @param rhs the value to write to the line
	/// @returns the utils::StringStream so calls can be chained
	template <typename T>
	utils::StringStream& operator<<(T&& rhs) {
	return os << std::forward<T>(rhs);
	}

	private:
	LineWriter(const LineWriter&) = delete;
	LineWriter& operator=(const LineWriter&) = delete;

	utils::StringStream os;
	TextBuffer* buffer;
	};

	/// Helper for writing a '(' on construction and a ')' destruction.
	struct ScopedParen {
	/// Constructor
	/// @param stream the utils::StringStream that will be written to
	explicit ScopedParen(utils::StringStream& stream);
	/// Destructor
	~ScopedParen();

	private:
	ScopedParen(ScopedParen&& rhs) = delete;
	ScopedParen(const ScopedParen&) = delete;
	ScopedParen& operator=(const ScopedParen&) = delete;
	utils::StringStream& s;
	};

	/// Helper for incrementing indentation on construction and decrementing
	/// indentation on destruction.
	struct ScopedIndent {
	/// Constructor
	/// @param buffer the TextBuffer that the ScopedIndent will indent
	explicit ScopedIndent(TextBuffer* buffer);
	/// Constructor
	/// @param generator ScopedIndent will indent the generator's
	/// `current_buffer_`
	explicit ScopedIndent(TextGenerator* generator);
	/// Destructor
	~ScopedIndent();

	private:
	ScopedIndent(ScopedIndent&& rhs) = delete;
	ScopedIndent(const ScopedIndent&) = delete;
	ScopedIndent& operator=(const ScopedIndent&) = delete;
	TextBuffer* buffer_;
	};

	/// @returns the resolved type of the ast::Expression `expr`
	/// @param expr the expression
	const type::Type* TypeOf(const ast::Expression* expr) const { return builder_.TypeOf(expr); }

	/// @returns the resolved type of the ast::TypeDecl `type_decl`
	/// @param type_decl the type
	const type::Type* TypeOf(const ast::TypeDecl* type_decl) const {
	return builder_.TypeOf(type_decl);
	}

	/// @returns a new LineWriter, used for buffering and writing a line to
	/// the end of #current_buffer_.
	LineWriter line() { return LineWriter(current_buffer_); }

	/// @param buffer the TextBuffer to write the line to
	/// @returns a new LineWriter, used for buffering and writing a line to
	/// the end of `buffer`.
	static LineWriter line(TextBuffer* buffer) { return LineWriter(buffer); }

	/// The program
	Program const* const program_;
	/// A ProgramBuilder that thinly wraps program_
	ProgramBuilder builder_;
	/// Diagnostics generated by the generator
	diag::List diagnostics_;
	/// The buffer the TextGenerator is currently appending lines to
	TextBuffer* current_buffer_ = &main_buffer_;

	private:
	/// The primary text buffer that the generator will emit
	TextBuffer main_buffer_;
	/// Map of builtin structure to unique generated name
	std::unordered_map<const sem::Struct*, std::string> builtin_struct_names_;
	};

	} // namespace tint::writer

	#endif // SRC_TINT_WRITER_TEXT_GENERATOR_H_