mirror of
https://github.com/netsurf-browser/netsurf
synced 2025-02-23 01:44:42 +03:00
Make llcache_object_user objects distinct from llcache_handles.
This allows us to be robust against clients completely changing the contents of the user list underneath us during iteration. Fix llcache_send_event_to_users to also be robust against the user list changing under it. svn path=/trunk/netsurf/; revision=11063
This commit is contained in:
John Mark Bell
parent
0e56e9c21b
commit
d745dae903
@ -62,8 +62,7 @@ struct llcache_handle {
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/** Low-level cache object user record */
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typedef struct llcache_object_user {
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/* Must be first in struct */
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llcache_handle handle; /**< Handle data for client */
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llcache_handle *handle; /**< Handle data for client */
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bool iterator_target; /**< This is the an iterator target */
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bool queued_for_delete; /**< This user is queued for deletion */
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@ -171,7 +170,9 @@ static nserror llcache_object_add_user(llcache_object *object,
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llcache_object_user *user);
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static nserror llcache_object_remove_user(llcache_object *object,
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llcache_object_user *user);
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static llcache_object_user *llcache_object_find_user(
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const llcache_handle *handle);
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static nserror llcache_object_add_to_list(llcache_object *object,
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llcache_object **list);
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static nserror llcache_object_remove_from_list(llcache_object *object,
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@ -258,6 +259,9 @@ void llcache_finalise(void)
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for (user = object->users; user != NULL; user = next_user) {
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next_user = user->next;
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if (user->handle != NULL)
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free(user->handle);
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free(user);
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}
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@ -276,6 +280,9 @@ void llcache_finalise(void)
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for (user = object->users; user != NULL; user = next_user) {
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next_user = user->next;
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if (user->handle != NULL)
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free(user->handle);
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free(user);
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}
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@ -351,7 +358,7 @@ nserror llcache_handle_retrieve(const char *url, uint32_t flags,
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/* Add user to object */
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llcache_object_add_user(object, user);
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*result = &user->handle;
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*result = user->handle;
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return NSERROR_OK;
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}
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@ -371,18 +378,22 @@ nserror llcache_handle_release(llcache_handle *handle)
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{
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nserror error = NSERROR_OK;
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llcache_object *object = handle->object;
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llcache_object_user *user = (llcache_object_user *) handle;
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llcache_object_user *user = llcache_object_find_user(handle);
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/* Remove the user from the object and destroy it */
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error = llcache_object_remove_user(object, user);
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if (error == NSERROR_OK) {
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/* Can't delete user object if it's the target of an iterator */
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if (user->iterator_target)
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user->queued_for_delete = true;
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else
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assert(user != NULL);
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if (user->iterator_target) {
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/* Can't remove / delete user object if it's
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* the target of an iterator */
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user->queued_for_delete = true;
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} else {
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/* Remove the user from the object and destroy it */
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error = llcache_object_remove_user(object, user);
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if (error == NSERROR_OK) {
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error = llcache_object_user_destroy(user);
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}
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}
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return error;
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}
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@ -395,8 +406,8 @@ nserror llcache_handle_clone(llcache_handle *handle, llcache_handle **result)
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error = llcache_object_user_new(handle->cb, handle->pw, &newuser);
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if (error == NSERROR_OK) {
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llcache_object_add_user(handle->object, newuser);
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newuser->handle.state = handle->state;
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*result = &newuser->handle;
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newuser->handle->state = handle->state;
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*result = newuser->handle;
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}
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return error;
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@ -405,7 +416,7 @@ nserror llcache_handle_clone(llcache_handle *handle, llcache_handle **result)
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/* See llcache.h for documentation */
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nserror llcache_handle_abort(llcache_handle *handle)
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{
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llcache_object_user *user = (llcache_object_user *) handle;
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llcache_object_user *user = llcache_object_find_user(handle);
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llcache_object *object = handle->object, *newobject;
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nserror error = NSERROR_OK;
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bool all_alone = true;
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@ -421,9 +432,29 @@ nserror llcache_handle_abort(llcache_handle *handle)
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error = llcache_object_snapshot(object, &newobject);
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if (error != NSERROR_OK)
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return error;
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/* Move across to the new object */
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llcache_object_remove_user(object, user);
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llcache_object_add_user(newobject, user);
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if (user->iterator_target) {
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/* User is current iterator target, clone it */
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llcache_object_user *newuser =
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calloc(1, sizeof(llcache_object_user));
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if (newuser == NULL) {
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llcache_object_destroy(newobject);
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return NSERROR_NOMEM;
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}
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/* Move handle across to clone */
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newuser->handle = user->handle;
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user->handle = NULL;
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/* Mark user as needing deletion */
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user->queued_for_delete = true;
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llcache_object_add_user(newobject, newuser);
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} else {
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llcache_object_remove_user(object, user);
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llcache_object_add_user(newobject, user);
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}
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/* Add new object to uncached list */
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llcache_object_add_to_list(newobject,
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@ -450,7 +481,7 @@ nserror llcache_handle_abort(llcache_handle *handle)
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/* See llcache.h for documentation */
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nserror llcache_handle_force_stream(llcache_handle *handle)
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{
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llcache_object_user *user = (llcache_object_user *) handle;
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llcache_object_user *user = llcache_object_find_user(handle);
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llcache_object *object = handle->object;
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/* Cannot stream if there are multiple users */
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@ -535,15 +566,26 @@ bool llcache_handle_references_same_object(const llcache_handle *a,
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nserror llcache_object_user_new(llcache_handle_callback cb, void *pw,
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llcache_object_user **user)
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{
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llcache_object_user *u = calloc(1, sizeof(llcache_object_user));
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if (u == NULL)
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llcache_handle *h;
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llcache_object_user *u;
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h = calloc(1, sizeof(llcache_handle));
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if (h == NULL)
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return NSERROR_NOMEM;
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u->handle.cb = cb;
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u->handle.pw = pw;
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u = calloc(1, sizeof(llcache_object_user));
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if (u == NULL) {
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free(h);
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return NSERROR_NOMEM;
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}
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h->cb = cb;
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h->pw = pw;
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u->handle = h;
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#ifdef LLCACHE_TRACE
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LOG(("Created user %p (%p, %p)", u, (void *) cb, pw));
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LOG(("Created user %p (%p, %p, %p)", u, h, (void *) cb, pw));
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#endif
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*user = u;
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@ -568,12 +610,16 @@ nserror llcache_object_user_destroy(llcache_object_user *user)
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assert(user->next == NULL);
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assert(user->prev == NULL);
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if (user->handle != NULL)
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free(user->handle);
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free(user);
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return NSERROR_OK;
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}
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/** Iterate the users of an object, calling their callbacks.
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/**
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* Iterate the users of an object, calling their callbacks.
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*
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* \param object The object to iterate
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* \param event The event to pass to the callback.
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@ -587,14 +633,25 @@ static nserror llcache_send_event_to_users(llcache_object *object,
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user = object->users;
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while (user != NULL) {
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next_user = user->next;
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error = user->handle.cb(&user->handle, event,
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user->handle.pw);
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user->iterator_target = true;
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error = user->handle->cb(user->handle, event,
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user->handle->pw);
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if (error != NSERROR_OK)
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break;
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next_user = user->next;
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user->iterator_target = false;
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if (user->queued_for_delete) {
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llcache_object_remove_user(object, user);
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llcache_object_user_destroy(user);
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}
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user = next_user;
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}
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return error;
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}
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@ -1156,7 +1213,7 @@ nserror llcache_object_add_user(llcache_object *object,
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assert(user->next == NULL);
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assert(user->prev == NULL);
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user->handle.object = object;
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user->handle->object = object;
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user->prev = NULL;
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user->next = object->users;
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@ -1183,7 +1240,7 @@ nserror llcache_object_remove_user(llcache_object *object,
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llcache_object_user *user)
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{
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assert(object->users != NULL);
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assert(user->handle.object == object);
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assert(user->handle->object == object);
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assert((user->prev != NULL) || (object->users == user));
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if (user == object->users)
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@ -1203,6 +1260,26 @@ nserror llcache_object_remove_user(llcache_object *object,
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return NSERROR_OK;
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}
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/**
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* Find a user of a low-level cache object
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*
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* \param handle External cache handle to search for
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* \return Pointer to corresponding user, or NULL if not found
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*/
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llcache_object_user *llcache_object_find_user(const llcache_handle *handle)
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{
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llcache_object_user *user;
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assert(handle->object != NULL);
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for (user = handle->object->users; user != NULL; user = user->next) {
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if (user->handle == handle)
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break;
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}
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return user;
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}
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/**
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* Add a low-level cache object to a cache list
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*
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@ -1305,7 +1382,7 @@ nserror llcache_object_notify_users(llcache_object *object)
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for (user = object->users; user != NULL; user = next_user) {
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/* Emit necessary events to bring the user up-to-date */
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llcache_handle *handle = &user->handle;
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llcache_handle *handle = user->handle;
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const llcache_fetch_state objstate = object->fetch.state;
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/* Flag that this user is the current iteration target
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@ -1373,6 +1450,7 @@ nserror llcache_object_notify_users(llcache_object *object)
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if (user->queued_for_delete) {
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next_user = user->next;
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llcache_object_remove_user(object, user);
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llcache_object_user_destroy(user);
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continue;
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}
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@ -1408,6 +1486,7 @@ nserror llcache_object_notify_users(llcache_object *object)
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if (user->queued_for_delete) {
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next_user = user->next;
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llcache_object_remove_user(object, user);
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llcache_object_user_destroy(user);
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continue;
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}
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@ -1429,6 +1508,7 @@ nserror llcache_object_notify_users(llcache_object *object)
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if (user->queued_for_delete) {
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next_user = user->next;
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llcache_object_remove_user(object, user);
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llcache_object_user_destroy(user);
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continue;
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}
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