118 lines
3.6 KiB
C++
118 lines
3.6 KiB
C++
// descriptors.h -- manage file descriptors for gold -*- C++ -*-
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// Copyright (C) 2008-2014 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#ifndef GOLD_DESCRIPTORS_H
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#define GOLD_DESCRIPTORS_H
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#include <vector>
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#include "gold-threads.h"
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namespace gold
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{
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// This class manages file descriptors for gold.
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class Descriptors
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{
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public:
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Descriptors();
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// Get a file descriptor for a file. The DESCRIPTOR parameter is
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// the descriptor the last time the file was used; this will be -1
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// if this is the first time the file is being opened. The NAME,
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// FLAGS, and MODE parameters are as for ::open. NAME must be in
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// permanent storage. This returns the descriptor to use, which may
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// or may not be the same as DESCRIPTOR. If there is an error
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// opening the file, this will return -1 with errno set
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// appropriately.
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int
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open(int descriptor, const char* name, int flags, int mode = 0);
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// Release the file descriptor DESCRIPTOR. If PERMANENT is true, it
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// will be closed, and the caller may not reopen it. If PERMANENT
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// is false this doesn't necessarily close the descriptor, but it
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// makes it available to be closed; the descriptor must not be used
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// again except as an argument to Descriptor::open.
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void
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release(int descriptor, bool permanent);
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// Close all the descriptors open for reading.
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void
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close_all();
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private:
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// Information kept for a descriptor.
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struct Open_descriptor
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{
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// File name currently associated with descriptor. This is empty
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// if none.
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const char* name;
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// Index of next descriptor on stack of released descriptors.
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int stack_next;
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// Whether the descriptor is currently in use.
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bool inuse;
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// Whether this is a write descriptor.
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bool is_write;
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// Whether the descriptor is on the stack.
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bool is_on_stack;
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};
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bool
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close_some_descriptor();
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// We need to lock before accessing any fields.
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Lock* lock_;
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// Used to initialize the lock_ field exactly once.
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Initialize_lock initialize_lock_;
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// Information for descriptors.
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std::vector<Open_descriptor> open_descriptors_;
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// Top of stack.
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int stack_top_;
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// The current number of file descriptors open.
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int current_;
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// The maximum number of file descriptors we open.
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int limit_;
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};
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// File descriptors are a centralized data structure, and we use a
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// global variable rather than passing the data structure into every
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// routine that does file I/O.
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extern Descriptors descriptors;
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inline int
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open_descriptor(int descriptor, const char* name, int flags, int mode = 0)
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{ return descriptors.open(descriptor, name, flags, mode); }
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inline void
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release_descriptor(int descriptor, bool permanent)
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{ descriptors.release(descriptor, permanent); }
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inline void
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close_all_descriptors()
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{ descriptors.close_all(); }
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} // End namespace gold.
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#endif // !defined(GOLD_DESCRIPTORS_H)
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