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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_COND_H
#define CEPH_COND_H
#include "common/Clock.h"
#include "common/ceph_mutex.h"
#include "include/Context.h"
/**
* context to signal a cond
*
* Generic context to signal a cond and store the return value. We
* assume the caller is holding the appropriate lock.
*/
class C_Cond : public Context {
ceph::condition_variable& cond; ///< Cond to signal
bool *done; ///< true if finish() has been called
int *rval; ///< return value
public:
C_Cond(ceph::condition_variable &c, bool *d, int *r) : cond(c), done(d), rval(r) {
*done = false;
}
void finish(int r) override {
*done = true;
*rval = r;
cond.notify_all();
}
};
/**
* context to signal a cond, protected by a lock
*
* Generic context to signal a cond under a specific lock. We take the
* lock in the finish() callback, so the finish() caller must not
* already hold it.
*/
class C_SafeCond : public Context {
ceph::mutex& lock; ///< Mutex to take
ceph::condition_variable& cond; ///< Cond to signal
bool *done; ///< true after finish() has been called
int *rval; ///< return value (optional)
public:
C_SafeCond(ceph::mutex& l, ceph::condition_variable& c, bool *d, int *r=0)
: lock(l), cond(c), done(d), rval(r) {
*done = false;
}
void finish(int r) override {
std::lock_guard l{lock};
if (rval)
*rval = r;
*done = true;
cond.notify_all();
}
};
/**
* Context providing a simple wait() mechanism to wait for completion
*
* The context will not be deleted as part of complete and must live
* until wait() returns.
*/
class C_SaferCond : public Context {
ceph::mutex lock; ///< Mutex to take
ceph::condition_variable cond; ///< Cond to signal
bool done = false; ///< true after finish() has been called
int rval = 0; ///< return value
public:
C_SaferCond() :
C_SaferCond("C_SaferCond")
{}
explicit C_SaferCond(const std::string &name)
: lock(ceph::make_mutex(name)) {}
void finish(int r) override { complete(r); }
/// We overload complete in order to not delete the context
void complete(int r) override {
std::lock_guard l(lock);
done = true;
rval = r;
cond.notify_all();
}
/// Returns rval once the Context is called
int wait() {
std::unique_lock l{lock};
cond.wait(l, [this] { return done;});
return rval;
}
/// Wait until the \c secs expires or \c complete() is called
int wait_for(double secs) {
return wait_for(ceph::make_timespan(secs));
}
int wait_for(ceph::timespan secs) {
std::unique_lock l{lock};
if (done) {
return rval;
}
if (cond.wait_for(l, secs, [this] { return done; })) {
return rval;
} else {
return ETIMEDOUT;
}
}
};
#endif
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