Implement a simple register and lookup for function tables. This is intended for plugins to expose APIs to other plugins. It has been very hard to arrange a plugin to be able to call into another plugin without modifying Weston core to explicitly support each case. This patch fixes that. The tests all pass. Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk> Signed-off-by: Giulio Camuffo <giuliocamuffo@gmail.com>dev
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/*
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* Copyright (C) 2016 DENSO CORPORATION |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining |
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* a copy of this software and associated documentation files (the |
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* "Software"), to deal in the Software without restriction, including |
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* without limitation the rights to use, copy, modify, merge, publish, |
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* distribute, sublicense, and/or sell copies of the Software, and to |
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* permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice (including the |
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* next paragraph) shall be included in all copies or substantial |
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* portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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*/ |
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#include "config.h" |
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#include <assert.h> |
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#include <string.h> |
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#include <stdlib.h> |
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#include "compositor.h" |
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#include "plugin-registry.h" |
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struct weston_plugin_api { |
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struct wl_list link; /**< in weston_compositor::plugin_api_list */ |
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char *api_name; /**< The search key */ |
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const void *vtable; /**< The function table */ |
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size_t vtable_size; /**< Size of the function table in bytes */ |
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}; |
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/** Register an implementation of an API
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* |
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* \param compositor The compositor instance. |
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* \param api_name The API name which other plugins use to find the |
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* implementation. |
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* \param vtable Pointer to the function table of the API. |
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* \param vtable_size Size of the function table in bytes. |
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* \return 0 on success, -1 on error, -2 if api_name already registered |
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* |
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* This call makes the given vtable to be reachable via |
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* weston_plugin_api_get(). Calls through the vtable may start happening |
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* as soon as the caller returns after success. Argument vtable must not be |
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* NULL. Argument api_name must be non-NULL and non-zero length. |
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* |
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* You can increase the function table size without breaking the ABI. |
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* To cater for ABI breaks, it is recommended to have api_name include a |
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* version number. |
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* |
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* A registered API cannot be unregistered. However, calls through a |
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* registered API must not be made from the compositor destroy signal handlers. |
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*/ |
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WL_EXPORT int |
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weston_plugin_api_register(struct weston_compositor *compositor, |
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const char *api_name, |
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const void *vtable, |
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size_t vtable_size) |
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{ |
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struct weston_plugin_api *wpa; |
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assert(api_name); |
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assert(strlen(api_name) > 0); |
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assert(vtable); |
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if (!api_name || !vtable || strlen(api_name) == 0) |
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return -1; |
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wl_list_for_each(wpa, &compositor->plugin_api_list, link) |
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if (strcmp(wpa->api_name, api_name) == 0) |
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return -2; |
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wpa = zalloc(sizeof(*wpa)); |
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if (!wpa) |
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return -1; |
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wpa->api_name = strdup(api_name); |
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wpa->vtable = vtable; |
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wpa->vtable_size = vtable_size; |
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if (!wpa->api_name) { |
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free(wpa); |
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return -1; |
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} |
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wl_list_insert(&compositor->plugin_api_list, &wpa->link); |
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weston_log("Registered plugin API '%s' of size %zd\n", |
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wpa->api_name, wpa->vtable_size); |
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return 0; |
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} |
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/** Internal function to free registered APIs
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* |
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* \param compositor The compositor instance. |
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*/ |
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void |
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weston_plugin_api_destroy_list(struct weston_compositor *compositor) |
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{ |
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struct weston_plugin_api *wpa, *tmp; |
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wl_list_for_each_safe(wpa, tmp, &compositor->plugin_api_list, link) { |
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free(wpa->api_name); |
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wl_list_remove(&wpa->link); |
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free(wpa); |
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} |
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} |
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/** Fetch the implementation of an API
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* |
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* \param compositor The compositor instance. |
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* \param api_name The name of the API to search for. |
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* \param vtable_size The expected function table size in bytes. |
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* \return Pointer to the function table, or NULL on error. |
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* |
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* Find the function table corresponding to api_name. The vtable_size here |
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* must be less or equal to the vtable_size given in the corresponding |
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* weston_plugin_api_register() call made by the implementing plugin. |
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* |
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* Calls can be made through the function table immediately. However, calls |
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* must not be made from or after the compositor destroy signal handler. |
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*/ |
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WL_EXPORT const void * |
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weston_plugin_api_get(struct weston_compositor *compositor, |
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const char *api_name, |
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size_t vtable_size) |
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{ |
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struct weston_plugin_api *wpa; |
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assert(api_name); |
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if (!api_name) |
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return NULL; |
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wl_list_for_each(wpa, &compositor->plugin_api_list, link) { |
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if (strcmp(wpa->api_name, api_name) != 0) |
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continue; |
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if (vtable_size <= wpa->vtable_size) |
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return wpa->vtable; |
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return NULL; |
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} |
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return NULL; |
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} |
@ -0,0 +1,55 @@ |
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/*
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* Copyright (C) 2016 DENSO CORPORATION |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining |
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* a copy of this software and associated documentation files (the |
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* "Software"), to deal in the Software without restriction, including |
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* without limitation the rights to use, copy, modify, merge, publish, |
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* distribute, sublicense, and/or sell copies of the Software, and to |
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* permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice (including the |
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* next paragraph) shall be included in all copies or substantial |
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* portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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*/ |
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#ifndef WESTON_PLUGIN_REGISTRY_H |
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#define WESTON_PLUGIN_REGISTRY_H |
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#include <stddef.h> |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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struct weston_compositor; |
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int |
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weston_plugin_api_register(struct weston_compositor *compositor, |
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const char *api_name, |
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const void *vtable, |
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size_t vtable_size); |
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const void * |
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weston_plugin_api_get(struct weston_compositor *compositor, |
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const char *api_name, |
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size_t vtable_size); |
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void |
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weston_plugin_api_destroy_list(struct weston_compositor *compositor); |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif /* WESTON_PLUGIN_REGISTRY_H */ |
@ -0,0 +1,101 @@ |
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/*
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* Copyright (C) 2016 DENSO CORPORATION |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining |
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* a copy of this software and associated documentation files (the |
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* "Software"), to deal in the Software without restriction, including |
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* without limitation the rights to use, copy, modify, merge, publish, |
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* distribute, sublicense, and/or sell copies of the Software, and to |
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* permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice (including the |
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* next paragraph) shall be included in all copies or substantial |
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* portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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*/ |
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#include "config.h" |
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#include <assert.h> |
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#include "compositor.h" |
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#include "plugin-registry.h" |
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static void |
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dummy_func(void) |
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{ |
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} |
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static const struct my_api { |
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void (*func1)(void); |
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void (*func2)(void); |
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void (*func3)(void); |
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} my_test_api = { |
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dummy_func, |
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dummy_func, |
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dummy_func, |
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}; |
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#define MY_API_NAME "test_my_api_v1" |
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static void |
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init_tests(struct weston_compositor *compositor) |
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{ |
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assert(weston_plugin_api_get(compositor, MY_API_NAME, |
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sizeof(my_test_api)) == NULL); |
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assert(weston_plugin_api_register(compositor, MY_API_NAME, &my_test_api, |
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sizeof(my_test_api)) == 0); |
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assert(weston_plugin_api_register(compositor, MY_API_NAME, &my_test_api, |
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sizeof(my_test_api)) == -2); |
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assert(weston_plugin_api_get(compositor, MY_API_NAME, |
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sizeof(my_test_api)) == &my_test_api); |
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assert(weston_plugin_api_register(compositor, "another", &my_test_api, |
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sizeof(my_test_api)) == 0); |
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} |
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static void |
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runtime_tests(void *data) |
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{ |
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struct weston_compositor *compositor = data; |
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const struct my_api *api; |
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size_t sz = sizeof(struct my_api); |
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assert(weston_plugin_api_get(compositor, MY_API_NAME, sz) == |
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&my_test_api); |
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assert(weston_plugin_api_get(compositor, MY_API_NAME, sz - 4) == |
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&my_test_api); |
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assert(weston_plugin_api_get(compositor, MY_API_NAME, sz + 4) == NULL); |
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api = weston_plugin_api_get(compositor, MY_API_NAME, sz); |
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assert(api && api->func2 == dummy_func); |
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wl_display_terminate(compositor->wl_display); |
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} |
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WL_EXPORT int |
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module_init(struct weston_compositor *compositor, int *argc, char *argv[]) |
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{ |
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struct wl_event_loop *loop; |
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init_tests(compositor); |
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loop = wl_display_get_event_loop(compositor->wl_display); |
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wl_event_loop_add_idle(loop, runtime_tests, compositor); |
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return 0; |
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} |
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Reference in new issue