/usr/include/ossim/base/Block.h is in libossim-dev 2.2.2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | #ifndef ossimBlock_HEADER
#define ossimBlock_HEADER 1
#include <ossim/base/ossimConstants.h>
#include <mutex>
#include <condition_variable>
#include <atomic>
namespace ossim{
/**
* This is a very simple block interface. This allows one to control
* how their threads are blocked
*
* There is a release state flag that tells the call to block to block the calling
* thread or release the thread(s) that are currently blocked
*
* For a very simple use case we will start a thread and call block and have
* the main sleep for 2 seconds before releasing the thread
* @code
* #include <ossim/base/Block.h>
* #include <ossim/base/Thread.h>
* std::shared_ptr<ossim::Block> block = std::make_shared<ossim::Block>();
* class TestThread : public ossim::Thread
* {
* public:
*
* protected:
* virtual void run(){
* block->block();
* std::cout << "STARING!!!!!!!\n";
* }
* };
* int main(int argc, char *argv[])
* {
* TestThread t1;
* t1.start();
*
* std::cout << "WAITING 2 SECOND to release block\n";
* ossim::Thread::sleepInSeconds(2);
* block->release();
* ossim::Thread::sleepInSeconds(2);
* }
* @endcode
*/
class OSSIM_DLL Block
{
public:
/**
* Allows one the construct a Block with a release state.
*/
Block(bool releaseFlag=false);
/**
* Destructor
*
* Will set internally call release
*/
~Block();
/**
* Will set the relase flag and wake up all threads to test the condition again.
*/
void set(bool releaseFlag);
/**
* Will block the calling thread based on the internal condition. If the internal
* condition is set to release then it will return without blocking.
*/
void block();
/**
* Will block the calling thread base on the internal condition. If the internal
* condition is set to release the it will return without blocking. If the internal
* condition is set to not release then it will block for the specified time in
* milliseconds
*
* @param waitTimeMillis specifies the amount of time to wait for the release
*/
void block(ossim_uint64 waitTimeMillis);
/**
* Releases the threads and will not return until all threads are released
*/
void release();
/**
* Simple reset the values. Will not do any releasing
*/
void reset();
private:
/**
* Used by the conditions
*/
mutable std::mutex m_mutex;
/**
* The release state.
*/
std::atomic<bool> m_release;
/**
* Condition that tests the release state
*/
std::condition_variable m_conditionVariable;
/**
* Used to count the number of threads blocked or
* waiting on the condition
*/
std::atomic<ossim_int32> m_waitCount;
/**
* Will be used for destructing and releasing.
* resetting should only happen in the main
* thread
*/
std::condition_variable m_conditionalWait;
};
}
#endif
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