src/core/lib/surface/channel_init.h

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#ifndef GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H
#define GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H

#include "src/core/lib/channel/channel_stack_builder.h"
#include "src/core/lib/surface/channel_stack_type.h"
#include "src/core/lib/transport/transport.h"

/// This module provides a way for plugins (and the grpc core library itself)
/// to register mutators for channel stacks.
/// It also provides a universal entry path to run those mutators to build
/// a channel stack for various subsystems.

/// One stage of mutation: call functions against \a builder to influence the
/// finally constructed channel stack
typedef bool (*grpc_channel_init_stage)(grpc_channel_stack_builder *builder,
                                        void *arg);

/// Global initialization of the system
void grpc_channel_init_init(void);

/// Register one stage of mutators.
/// Stages are run in priority order (lowest to highest), and then in
/// registration order (in the case of a tie).
/// Stages are registered against one of the pre-determined channel stack
/// types.
void grpc_channel_init_register_stage(grpc_channel_stack_type type,
                                      int priority,
                                      grpc_channel_init_stage stage_fn,
                                      void *stage_arg);

/// Finalize registration. No more calls to grpc_channel_init_register_stage are
/// allowed.
void grpc_channel_init_finalize(void);
/// Shutdown the channel init system
void grpc_channel_init_shutdown(void);

/// Construct a channel stack of some sort: see channel_stack.h for details
/// \a type is the type of channel stack to create
/// \a prefix_bytes is the number of bytes before the channel stack to allocate
/// \a args are configuration arguments for the channel stack
/// \a initial_refs is the initial refcount to give the channel stack
/// \a destroy and \a destroy_arg specify how to destroy the channel stack
///    if destroy_arg is NULL, the returned value from this function will be
///    substituted
/// \a optional_transport is either NULL or a constructed transport object
/// Returns a pointer to the base of the memory allocated (the actual channel
/// stack object will be prefix_bytes past that pointer)
void *grpc_channel_init_create_stack(
    grpc_exec_ctx *exec_ctx, grpc_channel_stack_type type, size_t prefix_bytes,
    const grpc_channel_args *args, int initial_refs, grpc_iomgr_cb_func destroy,
    void *destroy_arg, grpc_transport *optional_transport);

#endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H */