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Diffstat (limited to 'src/core/channel/channel_stack.h')
| -rw-r--r-- | src/core/channel/channel_stack.h | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/src/core/channel/channel_stack.h b/src/core/channel/channel_stack.h new file mode 100644 index 0000000000..0ae1005e67 --- /dev/null +++ b/src/core/channel/channel_stack.h @@ -0,0 +1,288 @@ +/* + * + * Copyright 2014, 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_INTERNAL_CHANNEL_CHANNEL_STACK_H__ +#define __GRPC_INTERNAL_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 <stddef.h> + +#include <grpc/grpc.h> +#include <grpc/support/log.h> +#include "src/core/transport/transport.h" + +/* #define GRPC_CHANNEL_STACK_TRACE 1 */ + +typedef struct grpc_channel_element grpc_channel_element; +typedef struct grpc_call_element grpc_call_element; + +/* Call operations - things that can be sent and received. + + Threading: + SEND, RECV, and CANCEL ops can be active on a call at the same time, but + only one SEND, one RECV, and one CANCEL can be active at a time. + + If state is shared between send/receive/cancel operations, it is up to + filters to provide their own protection around that. */ +typedef enum { + /* send metadata to the channels peer */ + GRPC_SEND_METADATA, + /* send a deadline */ + GRPC_SEND_DEADLINE, + /* start a connection (corresponds to start_invoke/accept) */ + GRPC_SEND_START, + /* send a message to the channels peer */ + GRPC_SEND_MESSAGE, + /* send half-close to the channels peer */ + GRPC_SEND_FINISH, + /* request that more data be allowed through flow control */ + GRPC_REQUEST_DATA, + /* metadata was received from the channels peer */ + GRPC_RECV_METADATA, + /* receive a deadline */ + GRPC_RECV_DEADLINE, + /* the end of the first batch of metadata was received */ + GRPC_RECV_END_OF_INITIAL_METADATA, + /* a message was received from the channels peer */ + GRPC_RECV_MESSAGE, + /* half-close was received from the channels peer */ + GRPC_RECV_HALF_CLOSE, + /* full close was received from the channels peer */ + GRPC_RECV_FINISH, + /* the call has been abnormally terminated */ + GRPC_CANCEL_OP +} grpc_call_op_type; + +/* The direction of the call. + The values of the enums (1, -1) matter here - they are used to increment + or decrement a pointer to find the next element to call */ +typedef enum { GRPC_CALL_DOWN = 1, GRPC_CALL_UP = -1 } grpc_call_dir; + +/* A single filterable operation to be performed on a call */ +typedef struct { + /* The type of operation we're performing */ + grpc_call_op_type type; + /* The directionality of this call - does the operation begin at the bottom + of the stack and flow up, or does the operation start at the top of the + stack and flow down through the filters. */ + grpc_call_dir dir; + + /* Flags associated with this call: see GRPC_WRITE_* in grpc.h */ + gpr_uint32 flags; + + /* Argument data, matching up with grpc_call_op_type names */ + union { + grpc_byte_buffer *message; + grpc_mdelem *metadata; + gpr_timespec deadline; + } data; + + /* Must be called when processing of this call-op is complete. + Signature chosen to match transport flow control callbacks */ + void (*done_cb)(void *user_data, grpc_op_error error); + /* User data to be passed into done_cb */ + void *user_data; +} grpc_call_op; + +/* returns a string representation of op, that can be destroyed with gpr_free */ +char *grpc_call_op_string(grpc_call_op *op); + +typedef enum { + GRPC_CHANNEL_SHUTDOWN, + GRPC_ACCEPT_CALL, + GRPC_TRANSPORT_CLOSED +} grpc_channel_op_type; + +/* A single filterable operation to be performed on a channel */ +typedef struct { + /* The type of operation we're performing */ + grpc_channel_op_type type; + /* The directionality of this call - is it bubbling up the stack, or down? */ + grpc_call_dir dir; + + /* Argument data, matching up with grpc_channel_op_type names */ + union { + struct { + grpc_transport *transport; + const void *transport_server_data; + } accept_call; + } data; +} grpc_channel_op; + +/* 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 (*call_op)(grpc_call_element *elem, grpc_call_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 (*channel_op)(grpc_channel_element *elem, grpc_channel_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_call_element *elem, + const void *server_transport_data); + /* Destroy per call data. + The filter does not need to do any chaining */ + void (*destroy_call_elem)(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_channel_element *elem, + const grpc_channel_args *args, + grpc_mdctx *metadata_context, int is_first, + int is_last); + /* Destroy per channel data. + The filter does not need to do any chaining */ + void (*destroy_channel_elem)(grpc_channel_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 */ +typedef struct { + size_t count; + /* Memory required for a call stack (computed at channel stack + initialization) */ + size_t call_stack_size; +} grpc_channel_stack; + +/* A call stack tracks a set of related filters for one call, and guarantees + they live within a single malloc() allocation */ +typedef struct { size_t count; } grpc_call_stack; + +/* 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(const grpc_channel_filter **filters, + size_t filter_count, const grpc_channel_args *args, + grpc_mdctx *metadata_context, + grpc_channel_stack *stack); +/* Destroy a channel stack */ +void grpc_channel_stack_destroy(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_channel_stack *channel_stack, + const void *transport_server_data, + grpc_call_stack *call_stack); +/* Destroy a call stack */ +void grpc_call_stack_destroy(grpc_call_stack *stack); + +/* Call the next operation (depending on call directionality) in a call stack */ +void grpc_call_next_op(grpc_call_element *elem, grpc_call_op *op); +/* Call the next operation (depending on call directionality) in a channel + stack */ +void grpc_channel_next_op(grpc_channel_element *elem, grpc_channel_op *op); + +/* 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_call_op *op); + +void grpc_call_element_send_metadata(grpc_call_element *cur_elem, + grpc_mdelem *elem); +void grpc_call_element_send_cancel(grpc_call_element *cur_elem); + +#ifdef GRPC_CHANNEL_STACK_TRACE +#define GRPC_CALL_LOG_OP(sev, elem, op) grpc_call_log_op(sev, elem, op) +#else +#define GRPC_CALL_LOG_OP(sev, elem, op) \ + do { \ + } while (0) +#endif + +#endif /* __GRPC_INTERNAL_CHANNEL_CHANNEL_STACK_H__ */ |