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// fileread.h -- read files for gold -*- C++ -*-
// Classes used to read data from binary input files.
#ifndef GOLD_FILEREAD_H
#define GOLD_FILEREAD_H
#include <string>
#include <list>
#include "options.h"
namespace gold
{
class Dirsearch;
class File_view;
// File_read manages a file descriptor for a file we are reading. We
// close file descriptors if we run out of them, so this class reopens
// the file as needed.
class File_read
{
public:
File_read()
: name_(), descriptor_(-1), lock_count_(0)
{ }
~File_read();
// Open a file.
bool
open(const std::string& name);
// Return the file name.
const std::string&
filename() const
{ return this->name_; }
// Return the file descriptor.
int
get_descriptor();
// Lock the file for access within a particular Task::run execution.
// This means that the descriptor can not be closed. This routine
// may only be called from the main thread.
void
lock();
// Unlock the descriptor, permitting it to be closed if necessary.
void
unlock();
// Test whether the object is locked.
bool
is_locked();
// Return a view into the file. The pointer will remain valid until
// the File_read is unlocked. If PBYTES is NULL, it is an error if
// we can not read enough data. Otherwise *PBYTES is set to the
// number of bytes read.
const unsigned char*
get_view(off_t start, off_t size, off_t *pbytes = NULL);
// Read data from the file into the buffer P. PBYTES is as in
// get_view.
void
read(off_t start, off_t size, void* p, off_t *pbytes = NULL);
// Return a lasting view into the file. This is allocated with new,
// and the caller is responsible for deleting it when done. The
// data associated with this view will remain valid until the view
// is deleted. PBYTES is handled as with get_view.
File_view*
get_lasting_view(off_t start, off_t size, off_t *pbytes = NULL);
private:
// This class may not be copied.
File_read(const File_read&);
File_read& operator=(const File_read&);
// A view into the file when not using mmap.
class View
{
public:
View(off_t start, off_t size, unsigned char* data)
: start_(start), size_(size), data_(data), lock_count_(0)
{ }
~View();
off_t
start() const
{ return this->start_; }
off_t
size() const
{ return this->size_; }
unsigned char*
data() const
{ return this->data_; }
void
lock();
void
unlock();
bool
is_locked();
private:
View(const View&);
View& operator=(const View&);
off_t start_;
off_t size_;
unsigned char* data_;
int lock_count_;
};
friend class File_view;
View*
find_view(off_t start, off_t size);
off_t
do_read(off_t start, off_t size, void* p, off_t* pbytes);
View*
find_or_make_view(off_t start, off_t size, off_t* pbytes);
void
clear_views(bool);
std::string name_;
int descriptor_;
int lock_count_;
std::list<View*> view_list_;
};
// A view of file data that persists even when the file is unlocked.
// Callers should destroy these when no longer required. These are
// obtained form File_read::get_lasting_view. They may only be
// destroyed when the underlying File_read is locked.
class File_view
{
public:
// This may only be called when the underlying File_read is locked.
~File_view();
// Return a pointer to the data associated with this view.
const unsigned char*
data() const
{ return this->data_; }
private:
File_view(const File_view&);
File_view& operator=(const File_view&);
friend class File_read;
// Callers have to get these via File_read::get_lasting_view.
File_view(File_read& file, File_read::View* view, const unsigned char* data)
: file_(file), view_(view), data_(data)
{ }
File_read& file_;
File_read::View* view_;
const unsigned char* data_;
};
// All the information we hold for a single input file. This can be
// an object file, a shared library, or an archive.
class Input_file
{
public:
Input_file(const Input_argument& input_argument)
: input_argument_(input_argument)
{ }
void
open(const General_options&, const Dirsearch&);
// Return the name given by the user.
const char*
name() const
{ return this->input_argument_.name(); }
// Return the file name.
const std::string&
filename() const
{ return this->file_.filename(); }
File_read&
file()
{ return this->file_; }
private:
const Input_argument& input_argument_;
File_read file_;
};
} // end namespace gold
#endif // !defined(GOLD_FILEREAD_H)
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