btr: Introduce btr_add_output_dont_free().

[paraslash.git] / buffer_tree.c

diff --git a/buffer_tree.c b/buffer_tree.c
index 5b4ce19e5f774fd8aaf67fdc42592339f1fb81ac..c62cbf13c3bdc4b621bd891d41e1b74fe24d98fe 100644 (file)
--- a/buffer_tree.c
+++ b/buffer_tree.c
@@ -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 {
@@ -319,7 +321,7 @@ 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);
 }
 
@@ -392,6 +394,34 @@ 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;
+
+       assert(size != 0);
+       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.
  *
@@ -544,9 +574,15 @@ 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)
@@ -729,44 +765,37 @@ 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)
-{
-       if (!btrn)
-               return;
-       free(btrn->name);
-       free(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);
+       free(btrn->name);
+       free(btrn);
+out:
+       *btrnp = NULL;
 }
 
 /**
@@ -825,6 +854,7 @@ void btr_splice_out_node(struct btr_node *btrn)
                        list_move(&ch->node, &btrn->parent->children);
        }
        assert(list_empty(&btrn->children));
+       btrn->parent = NULL;
 }
 
 /**
@@ -878,7 +908,7 @@ int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result)
                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, parent->name,
                                *value_result);
                return 1;
        }