file.h

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/**
 *  \file IMP/file.h
 *  \brief Handling of file input/output
 *
 *  Copyright 2007-2018 IMP Inventors. All rights reserved.
 *
 */

#ifndef IMPKERNEL_FILE_H
#define IMPKERNEL_FILE_H

#include <IMP/kernel_config.h>
#include "exception.h"
#include "internal/ifile.h"
#include "Pointer.h"
#include "Object.h"
#include "RAII.h"
#include "raii_macros.h"
#include "InputAdaptor.h"
#include "value_macros.h"
#include "check_macros.h"
#include <boost/shared_ptr.hpp>
#include <fstream>
#include <iostream>

IMPKERNEL_BEGIN_NAMESPACE

#if !defined(IMP_DOXYGEN)
template <class Stream>
struct TextProxy {
  Stream *str_;
  PointerMember<Object> ptr_;
  TextProxy(Stream *str, Object *ptr) : str_(str), ptr_(ptr) {}
};
#endif

/** A TextOutput can be implicitly constructed from a C++ stream, a
    Python filelike object or a path to a file. As a result, those can be
    passed directly to functions which take a TextOutput as an
    argument.

    Files are created lazily, so TextOutput can be passed as
    arguments to functions that might not produce output.
    \code
    IMP::atom::write_pdb(particles, "path/to/file.pdb");
    IMP::atom::write_pdb(particles, my_fstream);
    \endcode
    \see TextInput
*/
class IMPKERNELEXPORT TextOutput : public InputAdaptor {
  boost::shared_ptr<internal::IOStorage<std::ostream> > out_;

 public:
#ifndef IMP_DOXYGEN
  // SWIG needs these here for some bizarre reason
  TextOutput(int);
  TextOutput(double);
  TextOutput(const char *c, bool append = false);
  TextOutput(TextProxy<std::ostream> p);
#endif
  TextOutput() {}
  TextOutput(std::string file_name, bool append = false);
#ifndef SWIG
  TextOutput(std::ostream &out, std::string name = "C++ stream");
#endif

#if !defined(SWIG) && !defined(IMP_DOXYGEN)
  operator std::ostream &() { return get_stream(); }
  IMP_SAFE_BOOL(TextOutput, out_ &&out_->get_stream());
  std::ostream &get_stream() {
    IMP_USAGE_CHECK(out_, "Attempting to write to uninitialized text input");
    return out_->get_stream();
  }
#endif
  IMP_SHOWABLE_INLINE(TextOutput, out << get_name());
  std::string get_name() const { return out_->get_name(); }
};

/** A TextInput can be implicitly constructed from a C++ stream, a
    Python filelike object or a path to a file. As a result, those can be
    passed directly to functions which take a TextInput as an
    argument.
    \code
    IMP::atom::read_pdb("path/to/file.pdb", m);
    IMP::atom::read_pdb(my_fstream, m);
    \endcode
    \see TextOutput
*/
class IMPKERNELEXPORT TextInput : public InputAdaptor {
  boost::shared_ptr<internal::IOStorage<std::istream> > in_;

 public:
#ifndef IMP_DOXYGEN
  // SWIG needs these here for some bizarre reason
  TextInput(int);
  TextInput(double);
  TextInput(const char *c);
  TextInput(TextProxy<std::istream> p);
#endif
  TextInput() {}
  TextInput(std::string file_name);
#ifndef SWIG
  TextInput(std::istream &out, std::string name = "C++ stream");
#endif

#if !defined(SWIG) && !defined(IMP_DOXYGEN)
  operator std::istream &() { return get_stream(); }
  std::istream &get_stream() {
    if (!in_) {
      IMP_THROW("Attempting to read from uninitialized text input",
                IOException);
    }
    return in_->get_stream();
  }
#endif
  IMP_SHOWABLE_INLINE(TextInput, out << get_name());
  IMP_SAFE_BOOL(TextInput, in_ &&in_->get_stream());
  std::string get_name() const { return in_->get_name(); }
};

//! Set the target for the log.
/** See TextOutput for options. Python users should use
    SetLogTarget instead.
    \ingroup logging
 */
#ifndef SWIG
IMPKERNELEXPORT void set_log_target(TextOutput l);
IMPKERNELEXPORT TextOutput get_log_target();
#endif

/** Set the log target to a given value and reset it
    when the object is destroyed. Use this in Python
    to set the target of logs.
    \ingroup logging
*/
class SetLogTarget : public RAII {
  /* Python deletes all Python objects before static
     destructors are called. As a result, having static
     C++ objects point to Python objects is problematic.
     This class makes sure that the pointer to the
     Python class gets cleaned up when Python exits.
  */
  TextOutput old_;

 public:
  IMP_RAII(SetLogTarget, (TextOutput to), old_ = get_log_target();
           , set_log_target(to);, set_log_target(old_);, );
};

IMP_VALUES(TextInput, TextInputs);
IMP_VALUES(TextOutput, TextOutputs);

/** Create a temporary file. The path can be extracted from the TextOutput.

    If suffix is non-empty, there is some small chance of a collision on
    non-BSD systems as a unique temporary file is first created, and then
    a file with that suffix appended is created.*/
IMPKERNELEXPORT TextOutput create_temporary_file(std::string prefix = "imp_temp",
                                               std::string suffix = "");

//! Create a temporary file.
/** If suffix is non-empty, there is some small chance of a collision on
    non-BSD systems as a unique temporary file is first created, and then
    a file with that suffix appended is created. */
IMPKERNELEXPORT std::string create_temporary_file_name(std::string prefix =
                                                         "imp_temp",
                                                     std::string suffix = "");

//! Return a path to a file relative to another file.
/** For example
    if base is path/to/config.file and relative is data/image0.jpg
    then the return value would be path/to/data/image0.jpg. This
    function should be used when processing configuration files so
    that the meaning of the configuration file does not change if
    current working directory changes.
*/
IMPKERNELEXPORT std::string get_relative_path(std::string base,
                                            std::string relative);

//! Convert a possibly relative path to an absolute path.
/** If the provided path is a relative path, add the current working
    directory to make it an absolute path.

    \note If the path is already absolute, it is returned unchanged.
          Paths are not made canonical (symlinks or '..' elements are
    not removed). On Windows, the path is always returned unchanged.
  */
IMPKERNELEXPORT std::string get_absolute_path(std::string file);

IMPKERNEL_END_NAMESPACE

#endif /* IMPKERNEL_FILE_H */