lyx_mirror/src/graphics/GraphicsConverter.h

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// -*- C++ -*-
/*
* \file GraphicsConverter.h
* Copyright 2002 the LyX Team
* Read the file COPYING
*
* \author Angus Leeming <a.leeming@ic.ac.uk>
*
* class grfx::GConverter enables graphics files to be converted asynchronously
* to a loadable format. It does this by building a shell script of all
* the conversion commands needed for the transformation. This script is then
* sent to the forked calls controller for non-blocking execution. When it
* is finished a signal is emitted, thus informing us to proceed with the
* loading of the image.
*
* Ultimately, this class should be wrapped back into Dekel's converter class.
*/
#ifndef GRAPHICSCONVERTER_H
#define GRAPHICSCONVERTER_H
#include "LString.h"
#include "Lsstream.h"
#include <boost/smart_ptr.hpp>
#include <boost/utility.hpp>
#include <sigc++/signal_system.h>
#include <list>
#include <sys/types.h> // needed for pid_t
#ifdef __GNUG__
#pragma interface
#endif
namespace grfx {
class GConverter : boost::noncopyable {
public:
/// This is a singleton class. Get the instance.
static GConverter & get();
/// Can the conversion be performed?
bool isReachable(string const & from_format_name,
string const & to_format_name) const;
/** Convert the file and at the end return it by emitting this signal
* If successful, the returned string will be the name of the
* converted file (to_file_base + extension(to_format_name)).
* If unsuccessful, the string will be empty.
*/
typedef SigC::Signal1<void, string const &> SignalType;
///
typedef boost::shared_ptr<SignalType> SignalTypePtr;
///
void convert(string const & from_file, string const & to_file_base,
string const & from_format, string const & to_format,
SignalTypePtr on_finish);
private:
/** Make the c-tor private so we can control how many objects
* are instantiated.
*/
GConverter() {}
/** Build the conversion script, returning true if able to build it.
* The script is output to the ostringstream 'script'.
*/
bool build_script(string const & from_file, string const & to_file_base,
string const & from_format, string const & to_format,
ostringstream & script) const;
/** Remove the ConvProcess from the list of all processes.
* Called by ConvProcess::converted.
*/
friend class ConvProcess;
///
void erase(ConvProcess *);
/// The list of all conversion processs
typedef boost::shared_ptr<ConvProcess> ConvProcessPtr;
///
std::list<ConvProcessPtr> all_processes_;
};
/// Each ConvProcess represents a single conversion process.
struct ConvProcess : public SigC::Object
{
///
typedef GConverter::SignalTypePtr SignalTypePtr;
/** Each ConvProcess represents a single conversion process.
* It is passed :
* 1. The name of the script_file, which it deletes once the
* conversion is comlpeted;
* 2. The script command itself, which it passes on to the forked
* call process;
* 3. The name of the output file, which it returns to the calling
* process on successfull completion, by emitting
* 4. The signal on_finish.
*/
ConvProcess(string const & script_file, string const & script_command,
string const & to_file, SignalTypePtr on_finish);
/** This method is connected to a signal passed to the forked call
* class, passing control back here when the conversion is completed.
* Cleans-up the temporary files, emits the on_finish signal and
* removes the ConvProcess from the list of all processes.
*/
void converted(string const & cmd, pid_t pid, int retval);
///
string script_file_;
///
string to_file_;
///
SignalTypePtr on_finish_;
};
} // namespace grfx
#endif // GRAPHICSCONVERTER_H