X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=buffer_tree.c;h=b0cd6665416627806d922cda50fac2e2eeeab17f;hp=3a1f3e23eb75c7efc4df34942e9afdc7eda9af91;hb=06d0c50525fc14e8127916481a74c14a2f7098af;hpb=d16fe3df649cb48d5ffa26187da3dad4c3066646 diff --git a/buffer_tree.c b/buffer_tree.c index 3a1f3e23..b0cd6665 100644 --- a/buffer_tree.c +++ b/buffer_tree.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2009-2011 Andre Noll + * Copyright (C) 2009 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -30,6 +30,8 @@ struct btr_buffer { int refcount; /* NULL means no buffer pool but a malloced buffer. */ struct btr_pool *pool; + /* Only relevant if pool is NULL. */ + bool dont_free; }; struct btr_buffer_reference { @@ -293,9 +295,10 @@ struct btr_node *btr_new_node(struct btr_node_description *bnd) bnd->child->parent = btrn; goto out; } - PARA_EMERG_LOG("inserting internal nodes not yet supported.\n"); - exit(EXIT_FAILURE); - assert(bnd->child->parent == bnd->parent); + list_add_tail(&btrn->node, &bnd->parent->children); + list_move(&bnd->child->node, &btrn->children); + bnd->child->parent = btrn; + PARA_INFO_LOG("added %s as internal node\n", bnd->name); out: return btrn; } @@ -319,7 +322,7 @@ static void dealloc_buffer(struct btr_buffer *btrb) { if (btrb->pool) btr_pool_deallocate(btrb->pool, btrb->size); - else + else if (!btrb->dont_free) free(btrb->buf); } @@ -383,7 +386,8 @@ void btr_add_output(char *buf, size_t size, struct btr_node *btrn) { struct btr_buffer *btrb; - assert(size != 0); + if (size == 0) + return; if (list_empty(&btrn->children)) { free(buf); return; @@ -392,6 +396,35 @@ void btr_add_output(char *buf, size_t size, struct btr_node *btrn) add_btrb_to_children(btrb, btrn, 0); } +/** + * Insert a buffer into the buffer tree, non-freeing variant. + * + * \param buf See \ref btr_add_output(). + * \param size See \ref btr_add_output(). + * \param btrn See \ref btr_add_output(). + * + * This is similar to btr_add_output() but additionally sets the \p dont_free + * flag on \a buf. If the refcount for the buffer drops to zero, \a buf will + * not be deallocated if this flag is set. + * + * The \p dont_free bit also prevents the children of \a btrn from modifying + * the buffer contents inplace. Specifically, \ref btr_inplace_ok() returns + * false if there is any buffer in the input queue with the \p dont_free bit + * set. + */ +void btr_add_output_dont_free(const char *buf, size_t size, struct btr_node *btrn) +{ + struct btr_buffer *btrb; + + if (size == 0) + return; + if (list_empty(&btrn->children)) + return; + btrb = new_btrb((char *)buf, size); + btrb->dont_free = true; + add_btrb_to_children(btrb, btrn, 0); +} + /** * Feed data to child nodes of a buffer tree node. * @@ -411,7 +444,8 @@ void btr_add_output_pool(struct btr_pool *btrp, size_t size, char *buf; size_t avail; - assert(size != 0); + if (size == 0) + return; if (list_empty(&btrn->children)) return; avail = btr_pool_get_buffer(btrp, &buf); @@ -510,14 +544,16 @@ static bool btr_no_children(struct btr_node *btrn) } /** - * Find out whether a node is an orphan node. + * Find out whether a node is an orphan. * * \param btrn The buffer tree node. * * \return True if \a btrn has no parent. * - * This function will always return true for the root node. However in case - * nodes have been removed from the tree, other nodes may become orphans too. + * This function returns true for the root node and false for any other node. + * + * After a (non-leaf) node was removed removed from the tree, the function + * returns true for all child nodes. */ bool btr_no_parent(struct btr_node *btrn) { @@ -544,9 +580,15 @@ bool btr_no_parent(struct btr_node *btrn) */ bool btr_inplace_ok(struct btr_node *btrn) { - if (!btrn->parent) - return true; - return list_is_singular(&btrn->parent->children); + struct btr_buffer_reference *br; + FOR_EACH_BUFFER_REF(br, btrn) { + struct btr_buffer *btrb = br->btrb; + if (btrb->refcount > 1) + return false; + if (btrb->dont_free == true) + return false; + } + return true; } static inline size_t br_available_bytes(struct btr_buffer_reference *br) @@ -566,7 +608,7 @@ static size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char * * \param btrn The node whose input queue is to be queried. * \param omit Number of bytes to be omitted. - * \param bufp Result pointer. + * \param bufp Result pointer. It is OK to pass \p NULL here. * * If a buffer tree node needs more input data but can not consume the data it * already has (because it might be needed again later) this function can be @@ -729,17 +771,8 @@ void btr_drain(struct btr_node *btrn) btr_drop_buffer_reference(br); } -/** - * Free all resources allocated by btr_new_node(). - * - * \param btrn Pointer to a btr node obtained by \ref btr_new_node(). - * - * Like free(3), it is OK to call this with a \p NULL pointer argument. - */ -void btr_free_node(struct btr_node *btrn) +static void btr_free_node(struct btr_node *btrn) { - if (!btrn) - return; free(btrn->name); free(btrn); } @@ -747,26 +780,33 @@ void btr_free_node(struct btr_node *btrn) /** * Remove a node from a buffer tree. * - * \param btrn The node to remove. + * \param btrnp Determines the node to remove. * - * This makes all child nodes of \a btrn orphans and removes \a btrn from the - * list of children of its parent. Moreover, the input queue of \a btrn is - * flushed if it is not empty. + * This orphans all children of the node given by \a btrnp and removes this + * node from the child list of its parent. Moreover, the input queue is flushed + * and the node pointer given by \a btrp is set to \p NULL. * * \sa \ref btr_splice_out_node. */ -void btr_remove_node(struct btr_node *btrn) +void btr_remove_node(struct btr_node **btrnp) { struct btr_node *ch; + struct btr_node *btrn; - if (!btrn) + if (!btrnp) return; - PARA_NOTICE_LOG("removing btr node %s from buffer tree\n", btrn->name); + btrn = *btrnp; + if (!btrn) + goto out; + PARA_INFO_LOG("removing btr node %s from buffer tree\n", btrn->name); FOR_EACH_CHILD(ch, btrn) ch->parent = NULL; btr_drain(btrn); if (btrn->parent) list_del(&btrn->node); + btr_free_node(btrn); +out: + *btrnp = NULL; } /** @@ -800,7 +840,7 @@ size_t btr_get_input_queue_size(struct btr_node *btrn) /** * Remove a node from the buffer tree, reconnecting parent and children. * - * \param btrn The node to splice out. + * \param btrnp The node to splice out. * * This function is used by buffer tree nodes that do not exist during the * whole lifetime of the buffer tree. Unlike btr_remove_node(), calling @@ -808,9 +848,9 @@ size_t btr_get_input_queue_size(struct btr_node *btrn) * but reconnects the buffer tree by making all child nodes of \a btrn children * of the parent of \a btrn. */ -void btr_splice_out_node(struct btr_node *btrn) +void btr_splice_out_node(struct btr_node **btrnp) { - struct btr_node *ch, *tmp; + struct btr_node *btrn = *btrnp, *ch, *tmp; assert(btrn); PARA_NOTICE_LOG("splicing out %s\n", btrn->name); @@ -823,8 +863,12 @@ void btr_splice_out_node(struct btr_node *btrn) ch->parent = btrn->parent; if (btrn->parent) list_move(&ch->node, &btrn->parent->children); + else + list_del(&ch->node); } assert(list_empty(&btrn->children)); + btr_free_node(btrn); + *btrnp = NULL; } /** @@ -848,37 +892,36 @@ size_t btr_get_output_queue_size(struct btr_node *btrn) } /** - * Execute a inter-node command on a parent node. + * Execute an inter-node command on the given node or on a parent node. * * \param btrn The node to start looking. * \param command The command to execute. * \param value_result Additional arguments and result value. * - * This function traverses the buffer tree upwards and looks for parent nodes - * of \a btrn that understands \a command. On the first such node the command - * is executed, and the result is stored in \a value_result. + * This function traverses the buffer tree from \a btrn upwards and looks for + * the first node that understands \a command. On this node \a command is + * executed, and the result is stored in \a value_result. * * \return \p -ENOTSUP if no parent node of \a btrn understands \a command. * Otherwise the return value of the command handler is returned. + * + * \sa \ref receiver::execute, filter::execute, writer::execute. */ int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result) { int ret; for (; btrn; btrn = btrn->parent) { - struct btr_node *parent = btrn->parent; - if (!parent) - return -ERRNO_TO_PARA_ERROR(ENOTSUP); - if (!parent->execute) + if (!btrn->execute) continue; - PARA_INFO_LOG("parent: %s, cmd: %s\n", parent->name, command); - ret = parent->execute(parent, command, value_result); + PARA_INFO_LOG("executing %s on %s\n", command, btrn->name); + ret = btrn->execute(btrn, command, value_result); if (ret == -ERRNO_TO_PARA_ERROR(ENOTSUP)) continue; if (ret < 0) return ret; if (value_result && *value_result) - PARA_NOTICE_LOG("%s(%s): %s\n", command, parent->name, + PARA_INFO_LOG("%s(%s): %s\n", command, btrn->name, *value_result); return 1; } @@ -1166,21 +1209,20 @@ int btr_node_status(struct btr_node *btrn, size_t min_iqs, size_t iqs; assert(btrn); - if (type != BTR_NT_LEAF) { - if (btr_no_children(btrn)) - return -E_BTR_NO_CHILD; - if (btr_get_output_queue_size(btrn) > BTRN_MAX_PENDING) - return 0; - } - if (type != BTR_NT_ROOT) { - if (btr_eof(btrn)) - return -E_BTR_EOF; - iqs = btr_get_input_queue_size(btrn); - if (iqs == 0) /* we have a parent, because not eof */ - return 0; - if (iqs < min_iqs && !btr_no_parent(btrn)) - return 0; - } + if (type != BTR_NT_LEAF && btr_no_children(btrn)) + return -E_BTR_NO_CHILD; + if (type != BTR_NT_ROOT && btr_eof(btrn)) + return -E_BTR_EOF; + + if (btr_get_output_queue_size(btrn) > BTRN_MAX_PENDING) + return 0; + if (type == BTR_NT_ROOT) + return 1; + iqs = btr_get_input_queue_size(btrn); + if (iqs == 0) /* we have a parent, because not eof */ + return 0; + if (iqs < min_iqs && !btr_no_parent(btrn)) + return 0; return 1; } @@ -1196,3 +1238,18 @@ void btr_get_node_start(struct btr_node *btrn, struct timeval *tv) { *tv = btrn->start; } + +/** + * Get the parent node of a buffer tree node. + * + * \param btrn The node whose parent should be returned. + * + * \a btrn must not be \p NULL. + * + * \return The parent of \a btrn, or \p NULL if \a btrn is the + * root node of the buffer tree. + */ +struct btr_node *btr_parent(struct btr_node *btrn) +{ + return btrn->parent; +}