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#pragma once
#include "../goodies.h" // printStackTrace
namespace mongo {
/** some self-testing of synchronization and attempts to catch race conditions.
use something like:
CodeBlock myBlock;
void foo() {
CodeBlock::Within w(myBlock);
...
}
In _DEBUG builds, will (sometimes/maybe) fail if two threads are in the same code block at
the same time. Also detects and disallows recursion.
*/
#if defined(_DEBUG)
class CodeBlock {
volatile int n;
unsigned tid;
void fail() {
log() << "synchronization (race condition) failure" << endl;
printStackTrace();
abort();
}
void enter() {
if( ++n != 1 ) fail();
#if defined(_WIN32)
tid = GetCurrentThreadId();
#endif
}
void leave() {
if( --n != 0 ) fail();
}
public:
CodeBlock() : n(0) { }
class Within {
CodeBlock& _s;
public:
Within(CodeBlock& s) : _s(s) { _s.enter(); }
~Within() { _s.leave(); }
};
void assertWithin() {
assert( n == 1 );
#if defined(_WIN32)
assert( GetCurrentThreadId() == tid );
#endif
}
};
#else
class CodeBlock{
public:
class Within {
public:
Within(CodeBlock&) { }
};
void assertWithin() { }
};
#endif
}
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