diff options
author | Mark D. Roth <roth@google.com> | 2016-09-01 08:20:27 -0700 |
---|---|---|
committer | Mark D. Roth <roth@google.com> | 2016-09-01 08:20:27 -0700 |
commit | 2a5959f2aeca2e86cc752288d890bc10b24c55d0 (patch) | |
tree | d95da0b4b9b5987f4932496a16fe4ec96ecdc29d /src/core/ext/client_config | |
parent | 4c0fe49f76e0e3d7e7ceed5722cc43010af61ab3 (diff) |
A bit more cleanup.
Diffstat (limited to 'src/core/ext/client_config')
-rw-r--r-- | src/core/ext/client_config/client_channel.c | 655 |
1 files changed, 323 insertions, 332 deletions
diff --git a/src/core/ext/client_config/client_channel.c b/src/core/ext/client_config/client_channel.c index e4d7527ce8..fff80abb80 100644 --- a/src/core/ext/client_config/client_channel.c +++ b/src/core/ext/client_config/client_channel.c @@ -54,54 +54,9 @@ /* Client channel implementation */ -#define GET_CALL(call_data) \ - ((grpc_subchannel_call *)(gpr_atm_acq_load(&(call_data)->subchannel_call))) - -#define CANCELLED_CALL ((grpc_subchannel_call *)1) - -/** Picks a subchannel. - Returns true if subchannel is available immediately (in which case on_ready - should not be called), or false otherwise (in which case on_ready should be - called when the subchannel is available) */ -typedef bool (*pick_subchannel_cb)( - grpc_exec_ctx *exec_ctx, void *arg, grpc_metadata_batch *initial_metadata, - uint32_t initial_metadata_flags, - grpc_connected_subchannel **connected_subchannel, grpc_closure *on_ready); - -typedef enum { - GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING, - GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL -} subchannel_creation_phase; - -/** Call data. Holds a pointer to grpc_subchannel_call and the - associated machinery to create such a pointer. - Handles queueing of stream ops until a call object is ready, waiting - for initial metadata before trying to create a call object, - and handling cancellation gracefully. */ -typedef struct client_channel_call_data { - /** either 0 for no call, 1 for cancelled, or a pointer to a - grpc_subchannel_call */ - gpr_atm subchannel_call; - /** Helper function to choose the subchannel on which to create - the call object. Channel filter delegates to the load - balancing policy (once it's ready). */ - pick_subchannel_cb pick_subchannel; - void *pick_subchannel_arg; - - gpr_mu mu; - - subchannel_creation_phase creation_phase; - grpc_connected_subchannel *connected_subchannel; - grpc_polling_entity *pollent; - - grpc_transport_stream_op *waiting_ops; - size_t waiting_ops_count; - size_t waiting_ops_capacity; - - grpc_closure next_step; - - grpc_call_stack *owning_call; -} call_data; +/************************************************************************* + * CHANNEL-WIDE FUNCTIONS + */ typedef struct client_channel_channel_data { /** resolver for this channel */ @@ -140,215 +95,6 @@ typedef struct { grpc_lb_policy *lb_policy; } lb_policy_connectivity_watcher; -typedef struct { - grpc_closure closure; - grpc_call_element *elem; -} waiting_call; - -static void add_waiting_locked(call_data *calld, grpc_transport_stream_op *op) { - GPR_TIMER_BEGIN("add_waiting_locked", 0); - if (calld->waiting_ops_count == calld->waiting_ops_capacity) { - calld->waiting_ops_capacity = GPR_MAX(3, 2 * calld->waiting_ops_capacity); - calld->waiting_ops = - gpr_realloc(calld->waiting_ops, - calld->waiting_ops_capacity * sizeof(*calld->waiting_ops)); - } - calld->waiting_ops[calld->waiting_ops_count++] = *op; - GPR_TIMER_END("add_waiting_locked", 0); -} - -static void fail_locked(grpc_exec_ctx *exec_ctx, call_data *calld, - grpc_error *error) { - size_t i; - for (i = 0; i < calld->waiting_ops_count; i++) { - grpc_transport_stream_op_finish_with_failure( - exec_ctx, &calld->waiting_ops[i], GRPC_ERROR_REF(error)); - } - calld->waiting_ops_count = 0; - GRPC_ERROR_UNREF(error); -} - -typedef struct { - grpc_transport_stream_op *ops; - size_t nops; - grpc_subchannel_call *call; -} retry_ops_args; - -static void retry_ops(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) { - retry_ops_args *a = args; - size_t i; - for (i = 0; i < a->nops; i++) { - grpc_subchannel_call_process_op(exec_ctx, a->call, &a->ops[i]); - } - GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, a->call, "retry_ops"); - gpr_free(a->ops); - gpr_free(a); -} - -static void retry_waiting_locked(grpc_exec_ctx *exec_ctx, call_data *calld) { - retry_ops_args *a = gpr_malloc(sizeof(*a)); - a->ops = calld->waiting_ops; - a->nops = calld->waiting_ops_count; - a->call = GET_CALL(calld); - if (a->call == CANCELLED_CALL) { - gpr_free(a); - fail_locked(exec_ctx, calld, GRPC_ERROR_CANCELLED); - return; - } - calld->waiting_ops = NULL; - calld->waiting_ops_count = 0; - calld->waiting_ops_capacity = 0; - GRPC_SUBCHANNEL_CALL_REF(a->call, "retry_ops"); - grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(retry_ops, a), - GRPC_ERROR_NONE, NULL); -} - -static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg, - grpc_error *error) { - call_data *calld = arg; - gpr_mu_lock(&calld->mu); - GPR_ASSERT(calld->creation_phase == - GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL); - calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; - if (calld->connected_subchannel == NULL) { - gpr_atm_no_barrier_store(&calld->subchannel_call, 1); - fail_locked(exec_ctx, calld, GRPC_ERROR_CREATE_REFERENCING( - "Failed to create subchannel", &error, 1)); - } else if (1 == gpr_atm_acq_load(&calld->subchannel_call)) { - /* already cancelled before subchannel became ready */ - fail_locked(exec_ctx, calld, - GRPC_ERROR_CREATE_REFERENCING( - "Cancelled before creating subchannel", &error, 1)); - } else { - grpc_subchannel_call *subchannel_call = NULL; - grpc_error *new_error = grpc_connected_subchannel_create_call( - exec_ctx, calld->connected_subchannel, calld->pollent, - &subchannel_call); - if (new_error != GRPC_ERROR_NONE) { - new_error = grpc_error_add_child(new_error, error); - subchannel_call = CANCELLED_CALL; - fail_locked(exec_ctx, calld, new_error); - } - gpr_atm_rel_store(&calld->subchannel_call, - (gpr_atm)(uintptr_t)subchannel_call); - retry_waiting_locked(exec_ctx, calld); - } - gpr_mu_unlock(&calld->mu); - GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); -} - -static char *cc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) { - call_data *calld = elem->call_data; - grpc_subchannel_call *subchannel_call = GET_CALL(calld); - if (subchannel_call == NULL || subchannel_call == CANCELLED_CALL) { - return NULL; - } else { - return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call); - } -} - -// The logic here is fairly complicated, due to (a) the fact that we -// need to handle the case where we receive the send op before the -// initial metadata op, and (b) the need for efficiency, especially in -// the streaming case. -// TODO(ctiller): Explain this more thoroughly. -static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx, - grpc_call_element *elem, - grpc_transport_stream_op *op) { - call_data *calld = elem->call_data; - GRPC_CALL_LOG_OP(GPR_INFO, elem, op); - /* try to (atomically) get the call */ - grpc_subchannel_call *call = GET_CALL(calld); - GPR_TIMER_BEGIN("cc_start_transport_stream_op", 0); - if (call == CANCELLED_CALL) { - grpc_transport_stream_op_finish_with_failure(exec_ctx, op, - GRPC_ERROR_CANCELLED); - GPR_TIMER_END("cc_start_transport_stream_op", 0); - return; - } - if (call != NULL) { - grpc_subchannel_call_process_op(exec_ctx, call, op); - GPR_TIMER_END("cc_start_transport_stream_op", 0); - return; - } - /* we failed; lock and figure out what to do */ - gpr_mu_lock(&calld->mu); -retry: - /* need to recheck that another thread hasn't set the call */ - call = GET_CALL(calld); - if (call == CANCELLED_CALL) { - gpr_mu_unlock(&calld->mu); - grpc_transport_stream_op_finish_with_failure(exec_ctx, op, - GRPC_ERROR_CANCELLED); - GPR_TIMER_END("cc_start_transport_stream_op", 0); - return; - } - if (call != NULL) { - gpr_mu_unlock(&calld->mu); - grpc_subchannel_call_process_op(exec_ctx, call, op); - GPR_TIMER_END("cc_start_transport_stream_op", 0); - return; - } - /* if this is a cancellation, then we can raise our cancelled flag */ - if (op->cancel_error != GRPC_ERROR_NONE) { - if (!gpr_atm_rel_cas(&calld->subchannel_call, 0, - (gpr_atm)(uintptr_t)CANCELLED_CALL)) { - goto retry; - } else { - switch (calld->creation_phase) { - case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING: - fail_locked(exec_ctx, calld, GRPC_ERROR_REF(op->cancel_error)); - break; - case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL: - calld->pick_subchannel(exec_ctx, calld->pick_subchannel_arg, NULL, 0, - &calld->connected_subchannel, NULL); - break; - } - gpr_mu_unlock(&calld->mu); - grpc_transport_stream_op_finish_with_failure(exec_ctx, op, - GRPC_ERROR_CANCELLED); - GPR_TIMER_END("cc_start_transport_stream_op", 0); - return; - } - } - /* if we don't have a subchannel, try to get one */ - if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && - calld->connected_subchannel == NULL && - op->send_initial_metadata != NULL) { - calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL; - grpc_closure_init(&calld->next_step, subchannel_ready, calld); - GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel"); - if (calld->pick_subchannel( - exec_ctx, calld->pick_subchannel_arg, op->send_initial_metadata, - op->send_initial_metadata_flags, &calld->connected_subchannel, - &calld->next_step)) { - calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; - GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); - } - } - /* if we've got a subchannel, then let's ask it to create a call */ - if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && - calld->connected_subchannel != NULL) { - grpc_subchannel_call *subchannel_call = NULL; - grpc_error *error = grpc_connected_subchannel_create_call( - exec_ctx, calld->connected_subchannel, calld->pollent, - &subchannel_call); - if (error != GRPC_ERROR_NONE) { - subchannel_call = CANCELLED_CALL; - fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error)); - grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error); - } - gpr_atm_rel_store(&calld->subchannel_call, - (gpr_atm)(uintptr_t)subchannel_call); - retry_waiting_locked(exec_ctx, calld); - goto retry; - } - /* nothing to be done but wait */ - add_waiting_locked(calld, op); - gpr_mu_unlock(&calld->mu); - GPR_TIMER_END("cc_start_transport_stream_op", 0); -} - static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand, grpc_lb_policy *lb_policy, grpc_connectivity_state current_state); @@ -417,8 +163,8 @@ static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand, &w->on_changed); } -static void cc_on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg, - grpc_error *error) { +static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg, + grpc_error *error) { channel_data *chand = arg; grpc_lb_policy *lb_policy = NULL; grpc_lb_policy *old_lb_policy; @@ -570,6 +316,188 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx, gpr_mu_unlock(&chand->mu); } +/* Constructor for channel_data */ +static void cc_init_channel_elem(grpc_exec_ctx *exec_ctx, + grpc_channel_element *elem, + grpc_channel_element_args *args) { + channel_data *chand = elem->channel_data; + + memset(chand, 0, sizeof(*chand)); + + GPR_ASSERT(args->is_last); + GPR_ASSERT(elem->filter == &grpc_client_channel_filter); + + gpr_mu_init(&chand->mu); + grpc_closure_init(&chand->on_resolver_result_changed, + on_resolver_result_changed, chand); + chand->owning_stack = args->channel_stack; + + grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE, + "client_channel"); + chand->interested_parties = grpc_pollset_set_create(); +} + +/* Destructor for channel_data */ +static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx, + grpc_channel_element *elem) { + channel_data *chand = elem->channel_data; + + if (chand->resolver != NULL) { + grpc_resolver_shutdown(exec_ctx, chand->resolver); + GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel"); + } + if (chand->lb_policy != NULL) { + grpc_pollset_set_del_pollset_set(exec_ctx, + chand->lb_policy->interested_parties, + chand->interested_parties); + GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel"); + } + grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker); + grpc_pollset_set_destroy(chand->interested_parties); + gpr_mu_destroy(&chand->mu); +} + +/************************************************************************* + * PER-CALL FUNCTIONS + */ + +#define GET_CALL(call_data) \ + ((grpc_subchannel_call *)(gpr_atm_acq_load(&(call_data)->subchannel_call))) + +#define CANCELLED_CALL ((grpc_subchannel_call *)1) + +typedef enum { + GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING, + GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL +} subchannel_creation_phase; + +/** Call data. Holds a pointer to grpc_subchannel_call and the + associated machinery to create such a pointer. + Handles queueing of stream ops until a call object is ready, waiting + for initial metadata before trying to create a call object, + and handling cancellation gracefully. */ +typedef struct client_channel_call_data { + /** either 0 for no call, 1 for cancelled, or a pointer to a + grpc_subchannel_call */ + gpr_atm subchannel_call; + + gpr_mu mu; + + subchannel_creation_phase creation_phase; + grpc_connected_subchannel *connected_subchannel; + grpc_polling_entity *pollent; + + grpc_transport_stream_op *waiting_ops; + size_t waiting_ops_count; + size_t waiting_ops_capacity; + + grpc_closure next_step; + + grpc_call_stack *owning_call; +} call_data; + +static void add_waiting_locked(call_data *calld, grpc_transport_stream_op *op) { + GPR_TIMER_BEGIN("add_waiting_locked", 0); + if (calld->waiting_ops_count == calld->waiting_ops_capacity) { + calld->waiting_ops_capacity = GPR_MAX(3, 2 * calld->waiting_ops_capacity); + calld->waiting_ops = + gpr_realloc(calld->waiting_ops, + calld->waiting_ops_capacity * sizeof(*calld->waiting_ops)); + } + calld->waiting_ops[calld->waiting_ops_count++] = *op; + GPR_TIMER_END("add_waiting_locked", 0); +} + +static void fail_locked(grpc_exec_ctx *exec_ctx, call_data *calld, + grpc_error *error) { + size_t i; + for (i = 0; i < calld->waiting_ops_count; i++) { + grpc_transport_stream_op_finish_with_failure( + exec_ctx, &calld->waiting_ops[i], GRPC_ERROR_REF(error)); + } + calld->waiting_ops_count = 0; + GRPC_ERROR_UNREF(error); +} + +typedef struct { + grpc_transport_stream_op *ops; + size_t nops; + grpc_subchannel_call *call; +} retry_ops_args; + +static void retry_ops(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) { + retry_ops_args *a = args; + size_t i; + for (i = 0; i < a->nops; i++) { + grpc_subchannel_call_process_op(exec_ctx, a->call, &a->ops[i]); + } + GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, a->call, "retry_ops"); + gpr_free(a->ops); + gpr_free(a); +} + +static void retry_waiting_locked(grpc_exec_ctx *exec_ctx, call_data *calld) { + retry_ops_args *a = gpr_malloc(sizeof(*a)); + a->ops = calld->waiting_ops; + a->nops = calld->waiting_ops_count; + a->call = GET_CALL(calld); + if (a->call == CANCELLED_CALL) { + gpr_free(a); + fail_locked(exec_ctx, calld, GRPC_ERROR_CANCELLED); + return; + } + calld->waiting_ops = NULL; + calld->waiting_ops_count = 0; + calld->waiting_ops_capacity = 0; + GRPC_SUBCHANNEL_CALL_REF(a->call, "retry_ops"); + grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(retry_ops, a), + GRPC_ERROR_NONE, NULL); +} + +static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg, + grpc_error *error) { + call_data *calld = arg; + gpr_mu_lock(&calld->mu); + GPR_ASSERT(calld->creation_phase == + GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL); + calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; + if (calld->connected_subchannel == NULL) { + gpr_atm_no_barrier_store(&calld->subchannel_call, 1); + fail_locked(exec_ctx, calld, GRPC_ERROR_CREATE_REFERENCING( + "Failed to create subchannel", &error, 1)); + } else if (1 == gpr_atm_acq_load(&calld->subchannel_call)) { + /* already cancelled before subchannel became ready */ + fail_locked(exec_ctx, calld, + GRPC_ERROR_CREATE_REFERENCING( + "Cancelled before creating subchannel", &error, 1)); + } else { + grpc_subchannel_call *subchannel_call = NULL; + grpc_error *new_error = grpc_connected_subchannel_create_call( + exec_ctx, calld->connected_subchannel, calld->pollent, + &subchannel_call); + if (new_error != GRPC_ERROR_NONE) { + new_error = grpc_error_add_child(new_error, error); + subchannel_call = CANCELLED_CALL; + fail_locked(exec_ctx, calld, new_error); + } + gpr_atm_rel_store(&calld->subchannel_call, + (gpr_atm)(uintptr_t)subchannel_call); + retry_waiting_locked(exec_ctx, calld); + } + gpr_mu_unlock(&calld->mu); + GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); +} + +static char *cc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) { + call_data *calld = elem->call_data; + grpc_subchannel_call *subchannel_call = GET_CALL(calld); + if (subchannel_call == NULL || subchannel_call == CANCELLED_CALL) { + return NULL; + } else { + return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call); + } +} + typedef struct { grpc_metadata_batch *initial_metadata; uint32_t initial_metadata_flags; @@ -579,11 +507,11 @@ typedef struct { grpc_closure closure; } continue_picking_args; -static bool cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *arg, - grpc_metadata_batch *initial_metadata, - uint32_t initial_metadata_flags, - grpc_connected_subchannel **connected_subchannel, - grpc_closure *on_ready); +static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, + grpc_metadata_batch *initial_metadata, + uint32_t initial_metadata_flags, + grpc_connected_subchannel **connected_subchannel, + grpc_closure *on_ready); static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { @@ -592,22 +520,21 @@ static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, /* cancelled, do nothing */ } else if (error != GRPC_ERROR_NONE) { grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_REF(error), NULL); - } else if (cc_pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata, - cpa->initial_metadata_flags, - cpa->connected_subchannel, cpa->on_ready)) { + } else if (pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata, + cpa->initial_metadata_flags, + cpa->connected_subchannel, cpa->on_ready)) { grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_NONE, NULL); } gpr_free(cpa); } -static bool cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp, - grpc_metadata_batch *initial_metadata, - uint32_t initial_metadata_flags, - grpc_connected_subchannel **connected_subchannel, - grpc_closure *on_ready) { - GPR_TIMER_BEGIN("cc_pick_subchannel", 0); +static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, + grpc_metadata_batch *initial_metadata, + uint32_t initial_metadata_flags, + grpc_connected_subchannel **connected_subchannel, + grpc_closure *on_ready) { + GPR_TIMER_BEGIN("pick_subchannel", 0); - grpc_call_element *elem = elemp; channel_data *chand = elem->channel_data; call_data *calld = elem->call_data; continue_picking_args *cpa; @@ -631,19 +558,19 @@ static bool cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp, } } gpr_mu_unlock(&chand->mu); - GPR_TIMER_END("cc_pick_subchannel", 0); + GPR_TIMER_END("pick_subchannel", 0); return true; } if (chand->lb_policy != NULL) { grpc_lb_policy *lb_policy = chand->lb_policy; int r; - GRPC_LB_POLICY_REF(lb_policy, "cc_pick_subchannel"); + GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel"); gpr_mu_unlock(&chand->mu); r = grpc_lb_policy_pick(exec_ctx, lb_policy, calld->pollent, initial_metadata, initial_metadata_flags, connected_subchannel, on_ready); - GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "cc_pick_subchannel"); - GPR_TIMER_END("cc_pick_subchannel", 0); + GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "pick_subchannel"); + GPR_TIMER_END("pick_subchannel", 0); return r; } if (chand->resolver != NULL && !chand->started_resolving) { @@ -668,18 +595,118 @@ static bool cc_pick_subchannel(grpc_exec_ctx *exec_ctx, void *elemp, } gpr_mu_unlock(&chand->mu); - GPR_TIMER_END("cc_pick_subchannel", 0); + GPR_TIMER_END("pick_subchannel", 0); return false; } +// The logic here is fairly complicated, due to (a) the fact that we +// need to handle the case where we receive the send op before the +// initial metadata op, and (b) the need for efficiency, especially in +// the streaming case. +// TODO(ctiller): Explain this more thoroughly. +static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx, + grpc_call_element *elem, + grpc_transport_stream_op *op) { + call_data *calld = elem->call_data; + GRPC_CALL_LOG_OP(GPR_INFO, elem, op); + /* try to (atomically) get the call */ + grpc_subchannel_call *call = GET_CALL(calld); + GPR_TIMER_BEGIN("cc_start_transport_stream_op", 0); + if (call == CANCELLED_CALL) { + grpc_transport_stream_op_finish_with_failure(exec_ctx, op, + GRPC_ERROR_CANCELLED); + GPR_TIMER_END("cc_start_transport_stream_op", 0); + return; + } + if (call != NULL) { + grpc_subchannel_call_process_op(exec_ctx, call, op); + GPR_TIMER_END("cc_start_transport_stream_op", 0); + return; + } + /* we failed; lock and figure out what to do */ + gpr_mu_lock(&calld->mu); +retry: + /* need to recheck that another thread hasn't set the call */ + call = GET_CALL(calld); + if (call == CANCELLED_CALL) { + gpr_mu_unlock(&calld->mu); + grpc_transport_stream_op_finish_with_failure(exec_ctx, op, + GRPC_ERROR_CANCELLED); + GPR_TIMER_END("cc_start_transport_stream_op", 0); + return; + } + if (call != NULL) { + gpr_mu_unlock(&calld->mu); + grpc_subchannel_call_process_op(exec_ctx, call, op); + GPR_TIMER_END("cc_start_transport_stream_op", 0); + return; + } + /* if this is a cancellation, then we can raise our cancelled flag */ + if (op->cancel_error != GRPC_ERROR_NONE) { + if (!gpr_atm_rel_cas(&calld->subchannel_call, 0, + (gpr_atm)(uintptr_t)CANCELLED_CALL)) { + goto retry; + } else { + switch (calld->creation_phase) { + case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING: + fail_locked(exec_ctx, calld, GRPC_ERROR_REF(op->cancel_error)); + break; + case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL: + pick_subchannel(exec_ctx, elem, NULL, 0, + &calld->connected_subchannel, NULL); + break; + } + gpr_mu_unlock(&calld->mu); + grpc_transport_stream_op_finish_with_failure(exec_ctx, op, + GRPC_ERROR_CANCELLED); + GPR_TIMER_END("cc_start_transport_stream_op", 0); + return; + } + } + /* if we don't have a subchannel, try to get one */ + if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && + calld->connected_subchannel == NULL && + op->send_initial_metadata != NULL) { + calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL; + grpc_closure_init(&calld->next_step, subchannel_ready, calld); + GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel"); + if (pick_subchannel( + exec_ctx, elem, op->send_initial_metadata, + op->send_initial_metadata_flags, &calld->connected_subchannel, + &calld->next_step)) { + calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; + GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); + } + } + /* if we've got a subchannel, then let's ask it to create a call */ + if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && + calld->connected_subchannel != NULL) { + grpc_subchannel_call *subchannel_call = NULL; + grpc_error *error = grpc_connected_subchannel_create_call( + exec_ctx, calld->connected_subchannel, calld->pollent, + &subchannel_call); + if (error != GRPC_ERROR_NONE) { + subchannel_call = CANCELLED_CALL; + fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error)); + grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error); + } + gpr_atm_rel_store(&calld->subchannel_call, + (gpr_atm)(uintptr_t)subchannel_call); + retry_waiting_locked(exec_ctx, calld); + goto retry; + } + /* nothing to be done but wait */ + add_waiting_locked(calld, op); + gpr_mu_unlock(&calld->mu); + GPR_TIMER_END("cc_start_transport_stream_op", 0); +} + /* Constructor for call_data */ -static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx, - grpc_call_element *elem, - grpc_call_element_args *args) { +static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx, + grpc_call_element *elem, + grpc_call_element_args *args) { call_data *calld = elem->call_data; gpr_atm_rel_store(&calld->subchannel_call, 0); - calld->pick_subchannel = cc_pick_subchannel; - calld->pick_subchannel_arg = elem; gpr_mu_init(&calld->mu); calld->connected_subchannel = NULL; calld->waiting_ops = NULL; @@ -692,9 +719,10 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx, } /* Destructor for call_data */ -static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, - const grpc_call_final_info *final_info, - void *and_free_memory) { +static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx, + grpc_call_element *elem, + const grpc_call_final_info *final_info, + void *and_free_memory) { call_data *calld = elem->call_data; grpc_subchannel_call *call = GET_CALL(calld); if (call != NULL && call != CANCELLED_CALL) { @@ -707,47 +735,6 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, gpr_free(and_free_memory); } -/* Constructor for channel_data */ -static void init_channel_elem(grpc_exec_ctx *exec_ctx, - grpc_channel_element *elem, - grpc_channel_element_args *args) { - channel_data *chand = elem->channel_data; - - memset(chand, 0, sizeof(*chand)); - - GPR_ASSERT(args->is_last); - GPR_ASSERT(elem->filter == &grpc_client_channel_filter); - - gpr_mu_init(&chand->mu); - grpc_closure_init(&chand->on_resolver_result_changed, - cc_on_resolver_result_changed, chand); - chand->owning_stack = args->channel_stack; - - grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE, - "client_channel"); - chand->interested_parties = grpc_pollset_set_create(); -} - -/* Destructor for channel_data */ -static void destroy_channel_elem(grpc_exec_ctx *exec_ctx, - grpc_channel_element *elem) { - channel_data *chand = elem->channel_data; - - if (chand->resolver != NULL) { - grpc_resolver_shutdown(exec_ctx, chand->resolver); - GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel"); - } - if (chand->lb_policy != NULL) { - grpc_pollset_set_del_pollset_set(exec_ctx, - chand->lb_policy->interested_parties, - chand->interested_parties); - GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel"); - } - grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker); - grpc_pollset_set_destroy(chand->interested_parties); - gpr_mu_destroy(&chand->mu); -} - static void cc_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_polling_entity *pollent) { @@ -755,16 +742,20 @@ static void cc_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx, calld->pollent = pollent; } +/************************************************************************* + * EXPORTED SYMBOLS + */ + const grpc_channel_filter grpc_client_channel_filter = { cc_start_transport_stream_op, cc_start_transport_op, sizeof(call_data), - init_call_elem, + cc_init_call_elem, cc_set_pollset_or_pollset_set, - destroy_call_elem, + cc_destroy_call_elem, sizeof(channel_data), - init_channel_elem, - destroy_channel_elem, + cc_init_channel_elem, + cc_destroy_channel_elem, cc_get_peer, "client-channel", }; 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