Aegisub/src/subtitle_format.h

// Copyright (c) 2006, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/

#pragma once

#include <libaegisub/exception.h>
#include <libaegisub/fs_fwd.h>

#include <string>
#include <vector>

class AssFile;
namespace agi { namespace vfr { class Framerate; } }

class SubtitleFormat {
	std::string name;

	/// Get this format's wildcards for a load dialog
	virtual std::vector<std::string> GetReadWildcards() const { return {}; }
	/// Get this format's wildcards for a save dialog
	virtual std::vector<std::string> GetWriteWildcards() const { return {}; }

public:
	/// Strip override tags
	static void StripTags(AssFile &file);
	/// Convert newlines to the specified character(s)
	/// @param lineEnd newline character(s)
	/// @param mergeLineBreaks Should multiple consecutive line breaks be merged into one?
	static void ConvertNewlines(AssFile &file, std::string const& newline, bool mergeLineBreaks = true);
	/// Remove All commented and empty lines
	static void StripComments(AssFile &file);
	/// @brief Split and merge lines so there are no overlapping lines
	///
	/// Algorithm described at http://devel.aegisub.org/wiki/Technical/SplitMerge
	static void RecombineOverlaps(AssFile &file);
	/// Merge sequential identical lines
	static void MergeIdentical(AssFile &file);

	/// Prompt the user for a frame rate to use
	/// @param allow_vfr Include video frame rate as an option even if it's vfr
	/// @param show_smpte Show SMPTE drop frame option
	static agi::vfr::Framerate AskForFPS(bool allow_vfr, bool show_smpte, agi::vfr::Framerate const& fps);

	/// Constructor
	/// @param Subtitle format name
	SubtitleFormat(std::string name);
	/// Destructor
	virtual ~SubtitleFormat() = default;

	/// Get this format's name
	std::string const& GetName() const { return name; }

	/// @brief Check if the given file can be read by this format
	///
	/// Default implementation simply checks if the file's extension is in the
	/// format's wildcard list
	virtual bool CanReadFile(agi::fs::path const& filename, std::string const& encoding) const;

	/// @brief Check if the given file can be written by this format
	///
	/// Default implementation simply checks if the file's extension is in the
	/// format's wildcard list
	virtual bool CanWriteFile(agi::fs::path const& filename) const;

	/// @brief Check if the given subtitles can be losslessly written by this format
	///
	/// Default implementation rejects files with attachments, non-default
	/// styles, and any overrides
	virtual bool CanSave(const AssFile *file) const;

	/// Load a subtitle file
	/// @param[out] target Destination to read lines into
	/// @param filename File to load
	/// @param encoding Encoding to use. May be ignored by the reader.
	virtual void ReadFile(AssFile *target, agi::fs::path const& filename, agi::vfr::Framerate const& fps, std::string const& encoding) const { }

	/// Save a subtitle file
	/// @param src Data to write
	/// @param filename File to write to
	/// @param forceEncoding Encoding to use or empty string for default
	virtual void WriteFile(const AssFile *src, agi::fs::path const& filename, agi::vfr::Framerate const& fps, std::string const& encoding="") const { }

	/// Export a subtitle file
	///
	/// This is used when saving via Export As..., for subtitle formats which
	/// want to distinguish between exporting a final version of a script and
	/// saving a project.
	virtual void ExportFile(const AssFile *src, agi::fs::path const& filename, agi::vfr::Framerate const& fps, std::string const& encoding="") const {
		WriteFile(src, filename, fps, encoding);
	}

	/// Get the wildcards for a save or load dialog
	/// @param mode 0: load 1: save
	static std::string GetWildcards(int mode);

	/// Get a subtitle format that can read the given file or nullptr if none can
	static const SubtitleFormat *GetReader(agi::fs::path const& filename, std::string const& encoding);
	/// Get a subtitle format that can write the given file or nullptr if none can
	static const SubtitleFormat *GetWriter(agi::fs::path const& filename);
	/// Initialize subtitle formats
	static void LoadFormats();
};

DEFINE_EXCEPTION(SubtitleFormatParseError, agi::InvalidInputException);
DEFINE_EXCEPTION(UnknownSubtitleFormatError, agi::InvalidInputException);