diff options
Diffstat (limited to 'indra/llcommon/llprocess.cpp')
| -rw-r--r-- | indra/llcommon/llprocess.cpp | 96 |
1 files changed, 76 insertions, 20 deletions
diff --git a/indra/llcommon/llprocess.cpp b/indra/llcommon/llprocess.cpp index de71595f16..b13e8eb8e0 100644 --- a/indra/llcommon/llprocess.cpp +++ b/indra/llcommon/llprocess.cpp @@ -32,8 +32,10 @@ #include "stringize.h" #include "llapr.h" #include "apr_signal.h" +#include "llevents.h" #include <boost/foreach.hpp> +#include <boost/bind.hpp> #include <iostream> #include <stdexcept> @@ -47,6 +49,74 @@ struct LLProcessError: public std::runtime_error LLProcessError(const std::string& msg): std::runtime_error(msg) {} }; +/** + * Ref-counted "mainloop" listener. As long as there are still outstanding + * LLProcess objects, keep listening on "mainloop" so we can keep polling APR + * for process status. + */ +class LLProcessListener +{ + LOG_CLASS(LLProcessListener); +public: + LLProcessListener(): + mCount(0) + {} + + void addPoll(const LLProcess&) + { + // Unconditionally increment mCount. If it was zero before + // incrementing, listen on "mainloop". + if (mCount++ == 0) + { + LL_DEBUGS("LLProcess") << "listening on \"mainloop\"" << LL_ENDL; + mConnection = LLEventPumps::instance().obtain("mainloop") + .listen("LLProcessListener", boost::bind(&LLProcessListener::tick, this, _1)); + } + } + + void dropPoll(const LLProcess&) + { + // Unconditionally decrement mCount. If it's zero after decrementing, + // stop listening on "mainloop". + if (--mCount == 0) + { + LL_DEBUGS("LLProcess") << "disconnecting from \"mainloop\"" << LL_ENDL; + mConnection.disconnect(); + } + } + +private: + /// called once per frame by the "mainloop" LLEventPump + bool tick(const LLSD&) + { + // Tell APR to sense whether each registered LLProcess is still + // running and call handle_status() appropriately. We should be able + // to get the same info from an apr_proc_wait(APR_NOWAIT) call; but at + // least in APR 1.4.2, testing suggests that even with APR_NOWAIT, + // apr_proc_wait() blocks the caller. We can't have that in the + // viewer. Hence the callback rigmarole. (Once we update APR, it's + // probably worth testing again.) Also -- although there's an + // apr_proc_other_child_refresh() call, i.e. get that information for + // one specific child, it accepts an 'apr_other_child_rec_t*' that's + // mentioned NOWHERE else in the documentation or header files! I + // would use the specific call in LLProcess::getStatus() if I knew + // how. As it is, each call to apr_proc_other_child_refresh_all() will + // call callbacks for ALL still-running child processes. That's why we + // centralize such calls, using "mainloop" to ensure it happens once + // per frame, and refcounting running LLProcess objects to remain + // registered only while needed. + LL_DEBUGS("LLProcess") << "calling apr_proc_other_child_refresh_all()" << LL_ENDL; + apr_proc_other_child_refresh_all(APR_OC_REASON_RUNNING); + return false; + } + + /// If this object is destroyed before mCount goes to zero, stop + /// listening on "mainloop" anyway. + LLTempBoundListener mConnection; + unsigned mCount; +}; +static LLProcessListener sProcessListener; + LLProcessPtr LLProcess::create(const LLSDOrParams& params) { try @@ -159,6 +229,8 @@ LLProcess::LLProcess(const LLSDOrParams& params): // arrange to call status_callback() apr_proc_other_child_register(&mProcess, &LLProcess::status_callback, this, mProcess.in, gAPRPoolp); + // and make sure we poll it once per "mainloop" tick + sProcessListener.addPoll(*this); mStatus.mState = RUNNING; mDesc = STRINGIZE(LLStringUtil::quote(params.executable) << " (" << mProcess.pid << ')'); @@ -195,6 +267,8 @@ LLProcess::~LLProcess() // information updated in this object by such a callback is no longer // available to any consumer anyway. apr_proc_other_child_unregister(this); + // One less LLProcess to poll for + sProcessListener.dropPoll(*this); } if (mAutokill) @@ -228,26 +302,6 @@ bool LLProcess::isRunning(void) LLProcess::Status LLProcess::getStatus() { - // Only when mState is RUNNING might the status change dynamically. For - // any other value, pointless to attempt to update status: it won't - // change. - if (mStatus.mState == RUNNING) - { - // Tell APR to sense whether the child is still running and call - // handle_status() appropriately. We should be able to get the same - // info from an apr_proc_wait(APR_NOWAIT) call; but at least in APR - // 1.4.2, testing suggests that even with APR_NOWAIT, apr_proc_wait() - // blocks the caller. We can't have that in the viewer. Hence the - // callback rigmarole. Once we update APR, it's probably worth testing - // again. Also -- although there's an apr_proc_other_child_refresh() - // call, i.e. get that information for one specific child, it accepts - // an 'apr_other_child_rec_t*' that's mentioned NOWHERE else in the - // documentation or header files! I would use the specific call if I - // knew how. As it is, each call to this method will call callbacks - // for ALL still-running child processes. Sigh... - apr_proc_other_child_refresh_all(APR_OC_REASON_RUNNING); - } - return mStatus; } @@ -341,6 +395,8 @@ void LLProcess::handle_status(int reason, int status) // it already knows the child has terminated. We must pass the same 'data' // pointer as for the register() call, which was our 'this'. apr_proc_other_child_unregister(this); + // don't keep polling for a terminated process + sProcessListener.dropPoll(*this); // We overload mStatus.mState to indicate whether the child is registered // for APR callback: only RUNNING means registered. Track that we've // unregistered. We know the child has terminated; might be EXITED or |