#include "error.h"
#include "sched.h"
+/* whead = NULL means area full */
struct btr_pool {
char *name;
char *area_start;
char *whead;
};
-enum btr_buffer_flags {
- /* changes the way the buffer is deallocated */
- BTR_BF_BTR_POOL = 1,
-};
-
struct btr_buffer {
char *buf;
size_t size;
/** The number of references to this buffer. */
int refcount;
+ /* NULL means no buffer pool but a malloced buffer. */
struct btr_pool *pool;
};
void *context;
};
+/**
+ * Create a new buffer pool.
+ *
+ * \param name The name of the new buffer pool.
+ *
+ * \param area The size in bytes of the pool area.
+ *
+ * \return An opaque pointer to the newly created buffer pool. It must be
+ * passed to btr_pool_free() after it is no longer used to deallocate all
+ * resources.
+ */
struct btr_pool *btr_pool_new(const char *name, size_t area_size)
{
struct btr_pool *btrp;
return btrp;
}
-/* whead = NULL means area full */
-
+/**
+ * Dellocate resources used by a buffer pool.
+ *
+ * \param btrp A pointer obtained via btr_pool_new().
+ */
void btr_pool_free(struct btr_pool *btrp)
{
if (!btrp)
free(btrp);
}
+/**
+ * Return the size of the buffer pool area.
+ *
+ * \param btrp The buffer pool.
+ *
+ * \return The same value which was passed during creation time to
+ * btr_pool_new().
+ */
size_t btr_pool_size(struct btr_pool *btrp)
{
return btrp->area_end - btrp->area_start;
return btr_pool_size(btrp) - (btrp->rhead - btrp->whead);
}
+/**
+ * Get the number of unused bytes in the buffer pool.
+ *
+ * \param btrp The pool.
+ *
+ * \return The number of bytes that can currently be allocated.
+ *
+ * Note that in general the returned number of bytes is not available as a
+ * single contiguous buffer. Use btr_pool_available() to obtain the length of
+ * the largest contiguous buffer that can currently be allocated from the
+ * buffer pool.
+ */
size_t btr_pool_unused(struct btr_pool *btrp)
{
return btr_pool_size(btrp) - btr_pool_filled(btrp);
}
+/*
+ * Return maximal size available for one read. This is
+ * smaller than the value returned by btr_pool_unused().
+ */
size_t btr_pool_available(struct btr_pool *btrp)
{
if (!btrp->whead)
return btrp->rhead - btrp->whead;
}
+/**
+ * Obtain the current write head.
+ *
+ * \param btrp The buffer pool.
+ * \param result The write head is returned here.
+ *
+ * \return The maximal amount of bytes that may be written to the returned
+ * buffer.
+ */
size_t btr_pool_get_buffer(struct btr_pool *btrp, char **result)
{
if (result)
return btr_pool_available(btrp);
}
-void btr_pool_allocate(struct btr_pool *btrp, size_t size)
+/**
+ * Mark a part of the buffer pool area as allocated.
+ *
+ * \param btrp The buffer pool.
+ * \param size The amount of bytes to be allocated.
+ *
+ * This is usually called after the caller wrote to the buffer obtained by
+ * btr_pool_get_buffer().
+ */
+static void btr_pool_allocate(struct btr_pool *btrp, size_t size)
{
char *end;
if (size == 0)
return;
- //PARA_CRIT_LOG("filled: %zu, alloc %zu\n", btr_pool_filled(btrp), size);
assert(size <= btr_pool_available(btrp));
end = btrp->whead + size;
assert(end <= btrp->area_end);
end = btrp->area_start;
}
if (end == btrp->rhead) {
- PARA_DEBUG_LOG("btrp buffer full\n");
+ PARA_DEBUG_LOG("%s btrp buffer full\n", btrp->name);
end = NULL; /* buffer full */
}
btrp->whead = end;
- //PARA_CRIT_LOG("filled: %zu\n", btr_pool_filled(btrp));
}
static void btr_pool_deallocate(struct btr_pool *btrp, size_t size)
{
char *end = btrp->rhead + size;
- //PARA_CRIT_LOG("filled: %zu, dealloc %zu\n", btr_pool_filled(btrp), size);
if (size == 0)
return;
assert(end <= btrp->area_end);
btrp->rhead = end;
if (btrp->rhead == btrp->whead)
btrp->rhead = btrp->whead = btrp->area_start;
- //PARA_CRIT_LOG("filled: %zu\n", btr_pool_filled(btrp));
}
#define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
#define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
-struct btr_node *btr_new_node(const char *name, struct btr_node *parent,
- btr_command_handler handler, void *context)
+/**
+ * Create a new buffer tree node.
+ *
+ * \param bnd Specifies how to create the new node.
+ *
+ * This function always succeeds (or calls exit()). The returned pointer
+ * must be freed using btr_free_node() after it has been removed from
+ * the buffer tree via btr_remove_node().
+ */
+struct btr_node *btr_new_node(struct btr_node_description *bnd)
{
struct btr_node *btrn = para_malloc(sizeof(*btrn));
- btrn->name = para_strdup(name);
- btrn->parent = parent;
- btrn->execute = handler;
- btrn->context = context;
+ btrn->name = para_strdup(bnd->name);
+ btrn->parent = bnd->parent;
+ btrn->execute = bnd->handler;
+ btrn->context = bnd->context;
btrn->start.tv_sec = 0;
btrn->start.tv_usec = 0;
- if (parent)
- list_add_tail(&btrn->node, &parent->children);
INIT_LIST_HEAD(&btrn->children);
INIT_LIST_HEAD(&btrn->input_queue);
- if (parent)
- PARA_INFO_LOG("added %s as child of %s\n", name, parent->name);
- else
- PARA_INFO_LOG("added %s as btr root\n", name);
+ if (!bnd->child) {
+ if (bnd->parent) {
+ list_add_tail(&btrn->node, &bnd->parent->children);
+ PARA_INFO_LOG("new leaf node: %s (child of %s)\n",
+ bnd->name, bnd->parent->name);
+ } else
+ PARA_INFO_LOG("added %s as btr root\n", bnd->name);
+ goto out;
+ }
+ if (!bnd->parent) {
+ assert(!bnd->child->parent);
+ PARA_INFO_LOG("new root: %s (was %s)\n",
+ bnd->name, bnd->child->name);
+ btrn->parent = NULL;
+ list_add_tail(&bnd->child->node, &btrn->children);
+ /* link it in */
+ 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);
+out:
return btrn;
}
{
struct btr_buffer *btrb = br->btrb;
- //PARA_CRIT_LOG("dropping buffer reference %p\n", br);
list_del(&br->node);
free(br);
btrb->refcount--;
}
}
+/**
+ * Insert a malloced buffer into the buffer tree.
+ *
+ * \param buf The buffer to insert.
+ * \param size The size of \a buf in bytes.
+ * \param btrn Position in the buffer tree to create the output.
+ *
+ * This creates references to \a buf and adds these references to each child of
+ * \a btrn. The buffer will be freed using standard free() once no buffer tree
+ * node is referencing it any more.
+ *
+ * Note that this function must not be used if \a buf was obtained from a
+ * buffer pool. Use btr_add_output_pool() in this case.
+ */
void btr_add_output(char *buf, size_t size, struct btr_node *btrn)
{
struct btr_buffer *btrb;
add_btrb_to_children(btrb, btrn, 0);
}
+/**
+ * Feed data to child nodes of a buffer tree node.
+ *
+ * \param btrp The buffer pool.
+ * \param size The number of bytes to be allocated and fed to each child.
+ * \param btrn The node whose children are to be fed.
+ *
+ * This function allocates the amount of bytes from the buffer pool area,
+ * starting at the current value of the write head, and creates buffer
+ * references to the resulting part of the buffer pool area, one for each child
+ * of \a btrn. The references are then fed into the input queue of each child.
+ */
void btr_add_output_pool(struct btr_pool *btrp, size_t size,
struct btr_node *btrn)
{
add_btrb_to_children(btrb, btrn, 0);
}
+/**
+ * Copy data to write head of a buffer pool and feed it to all children nodes.
+ *
+ * \param src The source buffer.
+ * \param n The size of the source buffer in bytes.
+ * \param btrp The destination buffer pool.
+ * \param btrn Add the data as output of this node.
+ *
+ * This is expensive. The caller must make sure the data fits into the buffer
+ * pool area.
+ */
void btr_copy(const void *src, size_t n, struct btr_pool *btrp,
struct btr_node *btrn)
{
return 1;
}
-/* Return true if this node has no children. */
-bool btr_no_children(struct btr_node *btrn)
+/*
+ * Find out whether a node is a leaf node.
+ *
+ * \param btrn The node to check.
+ *
+ * \return True if this node has no children. False otherwise.
+ */
+static bool btr_no_children(struct btr_node *btrn)
{
return list_empty(&btrn->children);
}
+/**
+ * Find out whether a node is an orphan node.
+ *
+ * \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.
+ */
bool btr_no_parent(struct btr_node *btrn)
{
return !btrn->parent;
}
/**
- * \return zero if the input buffer queue is empty.
+ * Obtain the next buffer of the input queue of a buffer tree node.
+ *
+ * \param btrn The node whose input queue is to be queried.
+ * \param bufp Result pointer.
+ *
+ * \return The number of bytes that can be read from buf. Zero if the input
+ * buffer queue is empty. In this case the value of \a bufp is undefined.
*/
size_t btr_next_buffer(struct btr_node *btrn, char **bufp)
{
}
if (!br->btrb->pool)
break;
- if (result + rv != buf) {
- PARA_DEBUG_LOG("%s: pool merge impossible: %p != %p\n",
- btrn->name, result + rv, buf);
+ if (result + rv != buf)
break;
- }
-// PARA_CRIT_LOG("%s: inplace merge (%zu, %zu)->%zu\n", btrn->name,
-// rv, sz, rv + sz);
-// PARA_CRIT_LOG("%s: inplace merge %p (%zu)\n", btrn->name,
-// result, sz);
rv += sz;
}
if (bufp)
return rv;
}
+/**
+ * Deallocate the given number of bytes from the input queue.
+ *
+ * \param btrn The buffer tree node.
+ * \param numbytes The number of bytes to be deallocated.
+ *
+ * This function must be used to get rid of existing buffer references in the
+ * node's input queue. If no references to a buffer remain, the underlying
+ * buffers are either freed (in the non-buffer tree case) or the read head of
+ * the buffer pool is being advanced.
+ *
+ * Note that \a numbytes may be smaller than the buffer size. In this case the
+ * buffer is not deallocated and subsequent calls to btr_next_buffer() return
+ * the remaining part of the buffer.
+ */
void btr_consume(struct btr_node *btrn, size_t numbytes)
{
struct btr_buffer_reference *br, *tmp;
br = get_first_input_br(btrn);
assert(br);
- //PARA_CRIT_LOG("wrap count: %zu\n", br->wrap_count);
if (br->wrap_count == 0) {
/*
* No wrap buffer. Drop buffer references whose buffer
assert(true);
}
/*
-
- We have a wrap buffer, consume from it. If in total,
- i.e. including previous calls to brt_consume(), less than
- wrap_count has been consumed, there's nothing more we can do.
-
- Otherwise we drop the wrap buffer and consume from subsequent
- buffers of the input queue the correct amount of bytes. This
- is the total number of bytes that have been consumed from the
- wrap buffer.
-*/
+ * We have a wrap buffer, consume from it. If in total, i.e. including
+ * previous calls to brt_consume(), less than wrap_count has been
+ * consumed, there's nothing more we can do.
+ *
+ * Otherwise we drop the wrap buffer and consume from subsequent
+ * buffers of the input queue the correct amount of bytes. This is the
+ * total number of bytes that have been consumed from the wrap buffer.
+ */
PARA_DEBUG_LOG("consuming %zu/%zu bytes from wrap buffer\n", numbytes,
br_available_bytes(br));
list_del(&btrn->node);
}
+/**
+ * Return the amount of available input bytes of a buffer tree node.
+ *
+ * \param btrn The node whose input size should be computed.
+ *
+ * \return The total number of bytes available in the node's input
+ * queue.
+ *
+ * This simply iterates over all buffer references in the input queue and
+ * returns the sum of the sizes of all references.
+ */
size_t btr_get_input_queue_size(struct btr_node *btrn)
{
struct btr_buffer_reference *br;
- size_t size = 0;
+ size_t size = 0, wrap_consumed = 0;
FOR_EACH_BUFFER_REF(br, btrn) {
- //PARA_CRIT_LOG("size: %zu\n", size);
+ if (br->wrap_count != 0) {
+ wrap_consumed = br->consumed;
+ continue;
+ }
size += br_available_bytes(br);
}
+ assert(wrap_consumed <= size);
+ size -= wrap_consumed;
return size;
}
*
* Iterates over all children of the given node.
*/
-size_t btr_bytes_pending(struct btr_node *btrn)
+static size_t btr_bytes_pending(struct btr_node *btrn)
{
size_t max_size = 0;
struct btr_node *ch;
return btrn->execute(btrn, command, value_result);
}
+/**
+ * Execute a inter-node command.
+ */
int btr_exec_up(struct btr_node *btrn, const char *command, char **value_result)
{
int ret;
static void merge_input_pool(struct btr_node *btrn, size_t dest_size)
{
- struct btr_buffer_reference *br, *wbr;
+ struct btr_buffer_reference *br, *wbr = NULL;
int num_refs; /* including wrap buffer */
- char *buf, *buf1, *buf2 = NULL;
- size_t sz, sz1, sz2 = 0, wsz;
+ char *buf, *buf1 = NULL, *buf2 = NULL;
+ size_t sz, sz1 = 0, sz2 = 0, wsz;
- if (list_empty(&btrn->input_queue))
+ br = get_first_input_br(btrn);
+ if (!br || br_available_bytes(br) >= dest_size)
return;
-
num_refs = 0;
FOR_EACH_BUFFER_REF(br, btrn) {
num_refs++;
sz = btr_get_buffer_by_reference(br, &buf);
+ if (sz == 0)
+ break;
if (br->wrap_count != 0) {
assert(!wbr);
assert(num_refs == 1);
if (sz1 + sz2 >= dest_size)
break;
}
+ if (!buf2) /* nothing to do */
+ return;
+ assert(buf1 && sz2 > 0);
+ /*
+ * If the second buffer is large, we only take the first part of it to
+ * avoid having to memcpy() huge buffers.
+ */
+ sz2 = PARA_MIN(sz2, (size_t)(64 * 1024));
if (!wbr) {
- assert(buf1);
- if (!buf2) /* nothing to do */
- return;
- /* make a new wrap buffer combining buf1 and buf 2. */
+ /* Make a new wrap buffer combining buf1 and buf2. */
sz = sz1 + sz2;
buf = para_malloc(sz);
PARA_DEBUG_LOG("merging input buffers: (%p:%zu, %p:%zu) -> %p:%zu\n",
wsz = br_available_bytes(wbr);
if (wbr->wrap_count == sz1 && wbr->btrb->size >= sz1 + sz2) /* nothing we can do about it */
return;
- assert(buf1 && buf2);
sz = sz1 + sz2 - wbr->btrb->size; /* amount of new data */
+ PARA_DEBUG_LOG("increasing wrap buffer %zu -> %zu\n", wbr->btrb->size,
+ wbr->btrb->size + sz);
wbr->btrb->size += sz;
- PARA_DEBUG_LOG("increasing wrap buffer to %zu\n", wbr->btrb->size);
wbr->btrb->buf = para_realloc(wbr->btrb->buf, wbr->btrb->size);
/* copy the new data to the end of the reallocated buffer */
assert(sz2 >= sz);
if (i == 2)
break;
}
+ assert(i == 2);
/* make a new btrb that combines the two buffers and a br to it. */
sz = szs[0] + szs[1];
buf = para_malloc(sz);
return log_tree_recursively(btrn, loglevel, 0);
}
+/*
+ * \return \a root if \a name is \p NULL.
+ */
+struct btr_node *btr_search_node(const char *name, struct btr_node *root)
+{
+ struct btr_node *ch;
+
+ if (!name)
+ return root;
+ if (!strcmp(root->name, name))
+ return root;
+ FOR_EACH_CHILD(ch, root) {
+ struct btr_node *result = btr_search_node(name, ch);
+ if (result)
+ return result;
+ }
+ return NULL;
+}
+
/** 640K ought to be enough for everybody ;) */
#define BTRN_MAX_PENDING (640 * 1024)
{
size_t iqs;
- if (!btrn)
- return 0;
+ assert(btrn);
if (type != BTR_NT_LEAF) {
if (btr_no_children(btrn))
return -E_BTR_NO_CHILD;
projects / paraslash.git / blobdiff