Jordan Delong
363d1bb20f
This change is mostly for FB internal organizational reasons. Building is not effected beyond the fact that the target now lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
79 linhas
2.8 KiB
C++
79 linhas
2.8 KiB
C++
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<h2>How to Use HipHop Compiled Libraries in C++</h2>
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There are several functions that have to be called correctly to make sure
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HipHop compiled binaries work in a C++ environment:
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1. Without Memory Manager
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(1) hphp_process_init() and hphp_process_exit()
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The 1st function initializes all static variables a PHP library contains. This
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function is only needed to be called just ONCE before calling any other HipHop
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functions. Please call this function from process level (the "main thread")
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before starting any threads.
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Call hphp_process_exit() as the last HipHop function call when program exits.
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(2) hphp_session_init() and hphp_session_exit()
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If a PHP library does not have cycles in object references, one can call
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hphp_session_init() at the beginning of a "session" and then call
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hphp_session_exit() at the end of the session to free up all memory.
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Both functions have to be called on per-thread basis.
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2. With Memory Manager
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If memory leak is detected, it may mean the PHP library has objects or arrays
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forming cycles when referring to each other. This is problematic to reference
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counting based memory deallocation, but it can be solved by enabling the
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MemoryManager feature which sweeps memory when the current session is torn
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down.
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To enable MemorManager, this has to be set at program startup time, and it
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cannot be turned off afterwards:
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HPHP::RuntimeOption::EnableMemoryManager = true;
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MemoryManager::TheMemoryManager()->enable();
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(1) hphp_process_init()
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(same as above)
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(2) Recycle the session periodically
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It is a good idea to recycle the session periodically. The current session can
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be torn down by calling hphp_session_exit(), and subsequently a fresh session
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can be started by calling hphp_session_init().
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Please make sure there is no stack variables that are still alive when calling
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hphp_session_exit(). Otherwise, hphp_session_exit() will release the memory
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while there are still stack variables pointing to that memory.
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3. Thread Local Memory Management
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Almost all variables are thread-local. If you want to share those variables
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between threads, you will run into trouble. Instead, copy them into your own
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object classes to do so. Alternatively, use <b>apc_fetch()</b> and
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<b>apc_store()</b>.
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4. Execution Context
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Execution context controls where PHP's stdout goes to, whether to execute
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shutdown or postsend functions, etc.. It is optional to use it, but it's highly
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recommended to avoid calling functions that are not "pure".
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(1) At beginning of a session, set up execution context like this,
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ExecutionContext *context = hphp_context_init();
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(2) At end of a session, tear down execution context like this,
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hphp_context_exit(context, true);
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For the 2nd parameter, if true, post-send processing (PSP) will be performed,
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if false, all PSP functions will be ignored.
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