/* * * Copyright 2015-2016, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #ifndef GRPC_CORE_LIB_CHANNEL_CHANNEL_STACK_H #define GRPC_CORE_LIB_CHANNEL_CHANNEL_STACK_H /* A channel filter defines how operations on a channel are implemented. Channel filters are chained together to create full channels, and if those chains are linear, then channel stacks provide a mechanism to minimize allocations for that chain. Call stacks are created by channel stacks and represent the per-call data for that stack. */ #include #include #include #include "src/core/lib/debug/trace.h" #include "src/core/lib/transport/transport.h" typedef struct grpc_channel_element grpc_channel_element; typedef struct grpc_call_element grpc_call_element; typedef struct grpc_channel_stack grpc_channel_stack; typedef struct grpc_call_stack grpc_call_stack; typedef struct { grpc_channel_stack *channel_stack; const grpc_channel_args *channel_args; int is_first; int is_last; } grpc_channel_element_args; typedef struct { grpc_call_stack *call_stack; const void *server_transport_data; grpc_call_context_element *context; } grpc_call_element_args; /* Channel filters specify: 1. the amount of memory needed in the channel & call (via the sizeof_XXX members) 2. functions to initialize and destroy channel & call data (init_XXX, destroy_XXX) 3. functions to implement call operations and channel operations (call_op, channel_op) 4. a name, which is useful when debugging Members are laid out in approximate frequency of use order. */ typedef struct { /* Called to eg. send/receive data on a call. See grpc_call_next_op on how to call the next element in the stack */ void (*start_transport_stream_op)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_transport_stream_op *op); /* Called to handle channel level operations - e.g. new calls, or transport closure. See grpc_channel_next_op on how to call the next element in the stack */ void (*start_transport_op)(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_transport_op *op); /* sizeof(per call data) */ size_t sizeof_call_data; /* Initialize per call data. elem is initialized at the start of the call, and elem->call_data is what needs initializing. The filter does not need to do any chaining. server_transport_data is an opaque pointer. If it is NULL, this call is on a client; if it is non-NULL, then it points to memory owned by the transport and is on the server. Most filters want to ignore this argument. */ void (*init_call_elem)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_call_element_args *args); void (*set_pollset)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset); /* Destroy per call data. The filter does not need to do any chaining */ void (*destroy_call_elem)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem); /* sizeof(per channel data) */ size_t sizeof_channel_data; /* Initialize per-channel data. elem is initialized at the start of the call, and elem->channel_data is what needs initializing. is_first, is_last designate this elements position in the stack, and are useful for asserting correct configuration by upper layer code. The filter does not need to do any chaining */ void (*init_channel_elem)(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_channel_element_args *args); /* Destroy per channel data. The filter does not need to do any chaining */ void (*destroy_channel_elem)(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem); /* Implement grpc_call_get_peer() */ char *(*get_peer)(grpc_exec_ctx *exec_ctx, grpc_call_element *elem); /* The name of this filter */ const char *name; } grpc_channel_filter; /* A channel_element tracks its filter and the filter requested memory within a channel allocation */ struct grpc_channel_element { const grpc_channel_filter *filter; void *channel_data; }; /* A call_element tracks its filter, the filter requested memory within a channel allocation, and the filter requested memory within a call allocation */ struct grpc_call_element { const grpc_channel_filter *filter; void *channel_data; void *call_data; }; /* A channel stack tracks a set of related filters for one channel, and guarantees they live within a single malloc() allocation */ struct grpc_channel_stack { grpc_stream_refcount refcount; size_t count; /* Memory required for a call stack (computed at channel stack initialization) */ size_t call_stack_size; }; /* A call stack tracks a set of related filters for one call, and guarantees they live within a single malloc() allocation */ struct grpc_call_stack { /* shared refcount for this channel stack. MUST be the first element: the underlying code calls destroy with the address of the refcount, but higher layers prefer to think about the address of the call stack itself. */ grpc_stream_refcount refcount; size_t count; }; /* Get a channel element given a channel stack and its index */ grpc_channel_element *grpc_channel_stack_element(grpc_channel_stack *stack, size_t i); /* Get the last channel element in a channel stack */ grpc_channel_element *grpc_channel_stack_last_element( grpc_channel_stack *stack); /* Get a call stack element given a call stack and an index */ grpc_call_element *grpc_call_stack_element(grpc_call_stack *stack, size_t i); /* Determine memory required for a channel stack containing a set of filters */ size_t grpc_channel_stack_size(const grpc_channel_filter **filters, size_t filter_count); /* Initialize a channel stack given some filters */ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs, grpc_iomgr_cb_func destroy, void *destroy_arg, const grpc_channel_filter **filters, size_t filter_count, const grpc_channel_args *args, const char *name, grpc_channel_stack *stack); /* Destroy a channel stack */ void grpc_channel_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_channel_stack *stack); /* Initialize a call stack given a channel stack. transport_server_data is expected to be NULL on a client, or an opaque transport owned pointer on the server. */ void grpc_call_stack_init(grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack, int initial_refs, grpc_iomgr_cb_func destroy, void *destroy_arg, grpc_call_context_element *context, const void *transport_server_data, grpc_call_stack *call_stack); /* Set a pollset for a call stack: must occur before the first op is started */ void grpc_call_stack_set_pollset(grpc_exec_ctx *exec_ctx, grpc_call_stack *call_stack, grpc_pollset *pollset); #ifdef GRPC_STREAM_REFCOUNT_DEBUG #define GRPC_CALL_STACK_REF(call_stack, reason) \ grpc_stream_ref(&(call_stack)->refcount, reason) #define GRPC_CALL_STACK_UNREF(exec_ctx, call_stack, reason) \ grpc_stream_unref(exec_ctx, &(call_stack)->refcount, reason) #define GRPC_CHANNEL_STACK_REF(channel_stack, reason) \ grpc_stream_ref(&(channel_stack)->refcount, reason) #define GRPC_CHANNEL_STACK_UNREF(exec_ctx, channel_stack, reason) \ grpc_stream_unref(exec_ctx, &(channel_stack)->refcount, reason) #else #define GRPC_CALL_STACK_REF(call_stack, reason) \ grpc_stream_ref(&(call_stack)->refcount) #define GRPC_CALL_STACK_UNREF(exec_ctx, call_stack, reason) \ grpc_stream_unref(exec_ctx, &(call_stack)->refcount) #define GRPC_CHANNEL_STACK_REF(channel_stack, reason) \ grpc_stream_ref(&(channel_stack)->refcount) #define GRPC_CHANNEL_STACK_UNREF(exec_ctx, channel_stack, reason) \ grpc_stream_unref(exec_ctx, &(channel_stack)->refcount) #endif /* Destroy a call stack */ void grpc_call_stack_destroy(grpc_exec_ctx *exec_ctx, grpc_call_stack *stack); /* Ignore set pollset - used by filters to implement the set_pollset method if they don't care about pollsets at all. Does nothing. */ void grpc_call_stack_ignore_set_pollset(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_pollset *pollset); /* Call the next operation in a call stack */ void grpc_call_next_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_transport_stream_op *op); /* Call the next operation (depending on call directionality) in a channel stack */ void grpc_channel_next_op(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_transport_op *op); /* Pass through a request to get_peer to the next child element */ char *grpc_call_next_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem); /* Given the top element of a channel stack, get the channel stack itself */ grpc_channel_stack *grpc_channel_stack_from_top_element( grpc_channel_element *elem); /* Given the top element of a call stack, get the call stack itself */ grpc_call_stack *grpc_call_stack_from_top_element(grpc_call_element *elem); void grpc_call_log_op(char *file, int line, gpr_log_severity severity, grpc_call_element *elem, grpc_transport_stream_op *op); void grpc_call_element_send_cancel(grpc_exec_ctx *exec_ctx, grpc_call_element *cur_elem); extern int grpc_trace_channel; #define GRPC_CALL_LOG_OP(sev, elem, op) \ if (grpc_trace_channel) grpc_call_log_op(sev, elem, op) #endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_STACK_H */