| // fileread.h -- read files for gold -*- C++ -*- |
| |
| // Copyright 2006, 2007 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| // 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), size_(0), lock_count_(0), views_(), |
| saved_views_(), contents_(NULL), mapped_bytes_(0) |
| { } |
| |
| ~File_read(); |
| |
| // Open a file. |
| bool |
| open(const std::string& name); |
| |
| // Pretend to open the file, but provide the file contents. No |
| // actual file system activity will occur. This is used for |
| // testing. |
| bool |
| open(const std::string& name, const unsigned char* contents, off_t size); |
| |
| // Return the file name. |
| const std::string& |
| filename() const |
| { return this->name_; } |
| |
| // 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 the size of the file. |
| off_t |
| filesize() const |
| { return this->size_; } |
| |
| // Return a view into the file starting at file offset START for |
| // SIZE bytes. The pointer will remain valid until the File_read is |
| // unlocked. It is an error if we can not read enough data from the |
| // file. The CACHE parameter is a hint as to whether it will be |
| // useful to cache this data for later accesses--i.e., later calls |
| // to get_view, read, or get_lasting_view which retrieve the same |
| // data. |
| const unsigned char* |
| get_view(off_t start, off_t size, bool cache); |
| |
| // Read data from the file into the buffer P starting at file offset |
| // START for SIZE bytes. |
| void |
| read(off_t start, off_t size, void* p); |
| |
| // Return a lasting view into the file starting at file offset START |
| // for SIZE bytes. 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. It is an |
| // error if we can not read enough data from the file. The CACHE |
| // parameter is as in get_view. |
| File_view* |
| get_lasting_view(off_t start, off_t size, bool cache); |
| |
| // Dump statistical information to stderr. |
| static void |
| print_stats(); |
| |
| private: |
| // This class may not be copied. |
| File_read(const File_read&); |
| File_read& operator=(const File_read&); |
| |
| // Total bytes mapped into memory during the link. This variable is |
| // only accessed from the main thread, when unlocking the object. |
| static unsigned long long total_mapped_bytes; |
| |
| // Current number of bytes mapped into memory during the link. This |
| // variable is only accessed from the main thread. |
| static unsigned long long current_mapped_bytes; |
| |
| // High water mark of bytes mapped into memory during the link. |
| // This variable is only accessed from the main thread. |
| static unsigned long long maximum_mapped_bytes; |
| |
| // A view into the file. |
| class View |
| { |
| public: |
| View(off_t start, off_t size, const unsigned char* data, bool cache, |
| bool mapped) |
| : start_(start), size_(size), data_(data), lock_count_(0), |
| cache_(cache), mapped_(mapped) |
| { } |
| |
| ~View(); |
| |
| off_t |
| start() const |
| { return this->start_; } |
| |
| off_t |
| size() const |
| { return this->size_; } |
| |
| const unsigned char* |
| data() const |
| { return this->data_; } |
| |
| void |
| lock(); |
| |
| void |
| unlock(); |
| |
| bool |
| is_locked(); |
| |
| void |
| set_cache() |
| { this->cache_ = true; } |
| |
| bool |
| should_cache() const |
| { return this->cache_; } |
| |
| private: |
| View(const View&); |
| View& operator=(const View&); |
| |
| off_t start_; |
| off_t size_; |
| const unsigned char* data_; |
| int lock_count_; |
| bool cache_; |
| bool mapped_; |
| }; |
| |
| friend class View; |
| 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. |
| void |
| do_read(off_t start, off_t size, void* p); |
| |
| // Find or make a view into the file. |
| View* |
| find_or_make_view(off_t start, off_t size, bool cache); |
| |
| // 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_; |
| // File size. |
| off_t size_; |
| // 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_; |
| // Specified file contents. Used only for testing purposes. |
| const unsigned char* contents_; |
| // Total amount of space mapped into memory. This is only changed |
| // while the file is locked. When we unlock the file, we transfer |
| // the total to total_mapped_bytes, and reset this to zero. |
| size_t mapped_bytes_; |
| }; |
| |
| // 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), found_name_(), file_(), |
| is_in_sysroot_(false) |
| { } |
| |
| // Create an input file with the contents already provided. This is |
| // only used for testing. With this path, don't call the open |
| // method. |
| Input_file(const char* name, const unsigned char* contents, off_t size); |
| |
| // Open the file. If the open fails, this will report an error and |
| // return false. |
| bool |
| open(const General_options&, const Dirsearch&); |
| |
| // Return the name given by the user. For -lc this will return "c". |
| const char* |
| name() const |
| { return this->input_argument_->name(); } |
| |
| // Return the file name. For -lc this will return something like |
| // "/usr/lib/libc.so". |
| const std::string& |
| filename() const |
| { return this->file_.filename(); } |
| |
| // Return the name under which we found the file, corresponding to |
| // the command line. For -lc this will return something like |
| // "libc.so". |
| const std::string& |
| found_name() const |
| { return this->found_name_; } |
| |
| // Return the position dependent options. |
| const Position_dependent_options& |
| options() const |
| { return this->input_argument_->options(); } |
| |
| // Return the file. |
| File_read& |
| file() |
| { return this->file_; } |
| |
| // Whether we found the file in a directory in the system root. |
| bool |
| is_in_sysroot() const |
| { return this->is_in_sysroot_; } |
| |
| private: |
| Input_file(const Input_file&); |
| Input_file& operator=(const Input_file&); |
| |
| // The argument from the command line. |
| const Input_file_argument* input_argument_; |
| // The name under which we opened the file. This is like the name |
| // on the command line, but -lc turns into libc.so (or whatever). |
| // It only includes the full path if the path was on the command |
| // line. |
| std::string found_name_; |
| // The file after we open it. |
| File_read file_; |
| // Whether we found the file in a directory in the system root. |
| bool is_in_sysroot_; |
| }; |
| |
| } // end namespace gold |
| |
| #endif // !defined(GOLD_FILEREAD_H) |