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103 lines
3.4 KiB
Text
103 lines
3.4 KiB
Text
Copyright (c) 2009 Sun Microsystems, Inc.
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How to create a new service
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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A "service" is a set of C functions in a structure that a
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service dynamic linker uses when a dynamic plugin is loaded.
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If you want to export C++ class you need to provide an
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extern "C" function that will create a new instance of your class,
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and put it in a service.
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Data structures are not part of the service structure, but they are part
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of the API you create and usually need to be declared in the same
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service_*.h file.
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To turn a set of functions (foo_func1, foo_func2)
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into a service "foo" you need to
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1. create a new file include/mysql/service_foo.h
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2. the template is
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==================================================================
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#ifndef MYSQL_SERVICE_FOO_INCLUDED
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/* standard GPL header */
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/**
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@file
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*exhaustive* description of the interface you provide.
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This file is the main user documentation of the new service
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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extern struct foo_service_st {
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int (*foo_func1_ptr)(...); /* fix the prototype as appropriate */
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void (*foo_func2_ptr)(...); /* fix the prototype as appropriate */
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} *foo_service;
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#ifdef MYSQL_DYNAMIC_PLUGIN
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#define foo_func1(...) foo_service->foo_func1_ptr(...)
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#define foo_func2(...) foo_service->foo_func2_ptr(...)
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#else
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int foo_func1(...); /* fix the prototype as appropriate */
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void foo_func2(...); /* fix the prototype as appropriate */
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#endif
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#ifdef __cplusplus
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}
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#endif
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#define MYSQL_SERVICE_FOO_INCLUDED
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#endif
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==================================================================
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the service_foo.h file should be self-contained, if it needs system headers -
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include them in it, e.g. if you use size_t - #include <stdlib.h>
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it should also declare all the accompanying data structures, as necessary
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(e.g. thd_alloc_service declares MYSQL_LEX_STRING).
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3. add the new file to include/mysql/services.h
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4. increase the minor plugin ABI version in include/mysql/plugin.h
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(MARIA_PLUGIN_INTERFACE_VERSION = MARIA_PLUGIN_INTERFACE_VERSION+1)
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don't forget to update test result! e.g. use something like
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grep '\s\<1\.11\>' -r mysql-test
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5. add the version of your service to include/service_versions.h:
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==================================================================
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#define VERSION_foo 0x0100
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==================================================================
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6. create a new file libservices/foo_service.c using the following template:
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==================================================================
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/* GPL header */
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#include <service_versions.h>
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SERVICE_VERSION foo_service= (void*)VERSION_foo;
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==================================================================
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7. add the new file to libservices/CMakeLists.txt (MYSQLSERVICES_SOURCES)
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8. Add all new files to repository (git add)
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9. and finally, register your service for dynamic linking in
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sql/sql_plugin_services.ic as follows:
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9.1 fill in the service structure:
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==================================================================
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static struct foo_service_st foo_handler = {
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foo_func1,
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foo_func2
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}
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==================================================================
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9.2 and add it to the list of services
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==================================================================
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{ "foo_service", VERSION_foo, &foo_handler }
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==================================================================
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that's all.
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