| // 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 <list> |
| #include <map> |
| #include <string> |
| |
| #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; |
| |
| // Find a view into the file. |
| View* |
| find_view(off_t start, off_t size); |
| |
| // Read data from the file into a buffer. |
| off_t |
| do_read(off_t start, off_t size, void* p, off_t* pbytes); |
| |
| // Find or make a view into the file. |
| View* |
| find_or_make_view(off_t start, off_t size, off_t* pbytes); |
| |
| // Clear the file views. |
| void |
| clear_views(bool); |
| |
| // The size of a file page for buffering data. |
| static const off_t page_size = 8192; |
| |
| // Given a file offset, return the page offset. |
| static off_t |
| page_offset(off_t file_offset) |
| { return file_offset & ~ (page_size - 1); } |
| |
| // Given a file size, return the size to read integral pages. |
| static off_t |
| pages(off_t file_size) |
| { return (file_size + (page_size - 1)) & ~ (page_size - 1); } |
| |
| // The type of a mapping from page start to views. |
| typedef std::map<off_t, View*> Views; |
| |
| // A simple list of Views. |
| typedef std::list<View*> Saved_views; |
| |
| // File name. |
| std::string name_; |
| // File descriptor. |
| int descriptor_; |
| // Number of locks on the file. |
| int lock_count_; |
| // Buffered views into the file. |
| Views views_; |
| // List of views which were locked but had to be removed from views_ |
| // because they were not large enough. |
| Saved_views saved_views_; |
| }; |
| |
| // 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_file_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: |
| Input_file(const Input_file&); |
| Input_file& operator=(const Input_file&); |
| |
| const Input_file_argument& input_argument_; |
| File_read file_; |
| }; |
| |
| } // end namespace gold |
| |
| #endif // !defined(GOLD_FILEREAD_H) |