diff --git a/legacy/ecore/src/lib/ecore/ecore_private.h b/legacy/ecore/src/lib/ecore/ecore_private.h index 1f5bfde7cd..990c13af95 100644 --- a/legacy/ecore/src/lib/ecore/ecore_private.h +++ b/legacy/ecore/src/lib/ecore/ecore_private.h @@ -154,6 +154,62 @@ enum _Ecore_Exe_Flags ECORE_EXE_PIPE_WRITE = 2, ECORE_EXE_PIPE_READ_LINE_BUFFERED = 4, ECORE_EXE_RESPAWN = 8 + /* FIXME: Getting respawn to work + * + * There is no way that we can do anything about the internal state info of + * an external exe. The same can be said about the state of user code. User + * code in this context means the code that is using ecore_exe to manage exe's + * for it. + * + * Document that the exe must be respawnable, in other words, there is no + * state that it cannot regenerate by just killing it and starting it again. + * This includes state that the user code knows about, as the respawn is + * transparent to that code. On the other hand, maybe a respawn event might + * be useful, or maybe resend the currently non existant add event. For + * consistancy with ecore_con, an add event is good anyway. + * + * The Ecore_exe structure is reused for respawning, so that the (opaque) + * pointer held by the user remains valid. This means that the Ecore_Exe + * init and del functions may need to be split into two parts each to avoid + * duplicating code - common code part, and the rest. This implies that + * the unchanging members mentioned next should NEVER change. + * + * These structure members don't need to change - + * __list_data - we stay on the list + * ECORE_MAGIC - this is a constant + * data - passed in originally + * cmd - passed in originally + * flags - passed in originally + * + * These structure members need to change - + * tag - state that must be regenerated, zap it + * pid - it will be different + * child_fd_write - it will be different + * child_fd_read - it will be different + * write_fd_handler - we cannot change the fd used by a handler, this changes coz the fd changes. + * read_fd_handler - we cannot change the fd used by a handler, this changes coz the fd changes. + * + * Hmm, the read and write buffers could be tricky. + * They are not atomic, and could be in a semi complete state. + * They fall into the "state must be regenerated" mentioned above. + * A respawn/add event should take care of it. + * + * These structure members need to change - + * write_data_buf - state that must be regenerated, zap it + * write_data_size - state that must be regenerated, zap it + * write_data_offset - state that must be regenerated, zap it + * read_data_buf - state that must be regenerated, zap it + * read_data_size - state that must be regenerated, zap it + * close_write - state that must be regenerated, zap it + * + * There is the problem that an exe that fell over and needs respawning + * might keep falling over, keep needing to be respawned, and tie up system + * resources with the constant respawning. An exponentially increasing + * timeout (with maximum timeout) between respawns should take care of that. + * Although this is not a "contention for a resource" problem, the exe falling + * over may be, so a random element added to the timeout may help, and won't + * hurt. The user code may need to be informed that a timeout is in progress. + */ }; typedef enum _Ecore_Exe_Flags Ecore_Exe_Flags;