src/core/channel/channel_stack_builder.h

/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
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 * 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.
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 * this software without specific prior written permission.
 *
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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#ifndef GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_BUILDER_H
#define GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_BUILDER_H

#include <stdbool.h>

#include "src/core/channel/channel_args.h"
#include "src/core/channel/channel_stack.h"

// grpc_channel_stack_builder offers a programmatic interface to selected
// and order channel filters
typedef struct grpc_channel_stack_builder grpc_channel_stack_builder;
typedef struct grpc_channel_stack_builder_iterator
    grpc_channel_stack_builder_iterator;

// Create a new channel stack builder
grpc_channel_stack_builder *grpc_channel_stack_builder_create(void);

// Assign a name to the channel stack: string must be statically allocated
void grpc_channel_stack_builder_set_name(grpc_channel_stack_builder *builder,
                                         const char *name);

// Attach a transport to the builder (does not take ownership)
void grpc_channel_stack_builder_set_transport(
    grpc_channel_stack_builder *builder, grpc_transport *transport);

// Fetch attached transport
grpc_transport *grpc_channel_stack_builder_get_transport(
    grpc_channel_stack_builder *builder);

// Set channel arguments: they must continue to exist until after
// grpc_channel_stack_builder_finish returns
void grpc_channel_stack_builder_set_channel_arguments(
    grpc_channel_stack_builder *builder, const grpc_channel_args *args);

// Return a borrowed pointer to the channel arguments
const grpc_channel_args *grpc_channel_stack_builder_get_channel_arguments(
    grpc_channel_stack_builder *builder);

// Begin iterating over already defined filters in the builder
grpc_channel_stack_builder_iterator *
grpc_channel_stack_builder_create_iterator_at_first(
    grpc_channel_stack_builder *builder);
grpc_channel_stack_builder_iterator *
grpc_channel_stack_builder_create_iterator_at_last(
    grpc_channel_stack_builder *builder);

// Is an iterator at the first element?
bool grpc_channel_stack_builder_iterator_is_first(
    grpc_channel_stack_builder_iterator *iterator);

// Is an iterator at the end?
bool grpc_channel_stack_builder_iterator_is_end(
    grpc_channel_stack_builder_iterator *iterator);

// Move an iterator to the next item
bool grpc_channel_stack_builder_move_next(
    grpc_channel_stack_builder_iterator *iterator);

bool grpc_channel_stack_builder_move_prev(
    grpc_channel_stack_builder_iterator *iterator);

typedef void (*grpc_post_filter_create_init_func)(
    grpc_channel_stack *channel_stack, grpc_channel_element *elem, void *arg);

// Add a filter to the stack, after the given iterator
bool grpc_channel_stack_builder_add_filter_after(
    grpc_channel_stack_builder_iterator *iterator,
    const grpc_channel_filter *filter,
    grpc_post_filter_create_init_func post_init_func,
    void *user_data) GRPC_MUST_USE_RESULT;

// Add a filter to the stack, before the given iterator
bool grpc_channel_stack_builder_add_filter_before(
    grpc_channel_stack_builder_iterator *iterator,
    const grpc_channel_filter *filter,
    grpc_post_filter_create_init_func post_init_func,
    void *user_data) GRPC_MUST_USE_RESULT;

// Add a filter to the beginning of the filter list
bool grpc_channel_stack_builder_prepend_filter(
    grpc_channel_stack_builder *builder, const grpc_channel_filter *filter,
    grpc_post_filter_create_init_func post_init_func,
    void *user_data) GRPC_MUST_USE_RESULT;

// Add a filter to the end of the filter list
bool grpc_channel_stack_builder_append_filter(
    grpc_channel_stack_builder *builder, const grpc_channel_filter *filter,
    grpc_post_filter_create_init_func post_init_func,
    void *user_data) GRPC_MUST_USE_RESULT;

// Terminate iteration
void grpc_channel_stack_builder_iterator_destroy(
    grpc_channel_stack_builder_iterator *iterator);

// Destroy the builder, return the freshly minted channel stack
void *grpc_channel_stack_builder_finish(grpc_exec_ctx *exec_ctx,
                                        grpc_channel_stack_builder *builder,
                                        size_t prefix_bytes, int initial_refs,
                                        grpc_iomgr_cb_func destroy,
                                        void *destroy_arg);

// Destroy the builder without creating a channel stack
void grpc_channel_stack_builder_destroy(grpc_channel_stack_builder *builder);

#endif