#include "cache.h"
#include "notes.h"
+#include "tree.h"
#include "utf8.h"
#include "strbuf.h"
#include "tree-walk.h"
#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
(memcmp(key_sha1, subtree_sha1, subtree_sha1[19]))
-static struct int_node root_node;
-
-static int initialized;
+struct notes_tree default_notes_tree;
static void load_subtree(struct leaf_node *subtree, struct int_node *node,
unsigned int n);
* - Replace the matching leaf_node with a NULL entry (and free the leaf_node).
* - Consolidate int_nodes repeatedly, while walking up the tree towards root.
*/
-static void note_tree_remove(struct int_node *tree, unsigned char n,
- struct leaf_node *entry)
+static void note_tree_remove(struct notes_tree *t, struct int_node *tree,
+ unsigned char n, struct leaf_node *entry)
{
struct leaf_node *l;
struct int_node *parent_stack[20];
if (!n)
return; /* cannot consolidate top level */
/* first, build stack of ancestors between root and current node */
- parent_stack[0] = &root_node;
+ parent_stack[0] = t->root;
for (i = 0; i < n; i++) {
j = GET_NIBBLE(i, entry->key_sha1);
parent_stack[i + 1] = CLR_PTR_TYPE(parent_stack[i]->a[j]);
free(buf);
}
-void init_notes(const char *notes_ref, int flags)
+/*
+ * Determine optimal on-disk fanout for this part of the notes tree
+ *
+ * Given a (sub)tree and the level in the internal tree structure, determine
+ * whether or not the given existing fanout should be expanded for this
+ * (sub)tree.
+ *
+ * Values of the 'fanout' variable:
+ * - 0: No fanout (all notes are stored directly in the root notes tree)
+ * - 1: 2/38 fanout
+ * - 2: 2/2/36 fanout
+ * - 3: 2/2/2/34 fanout
+ * etc.
+ */
+static unsigned char determine_fanout(struct int_node *tree, unsigned char n,
+ unsigned char fanout)
+{
+ /*
+ * The following is a simple heuristic that works well in practice:
+ * For each even-numbered 16-tree level (remember that each on-disk
+ * fanout level corresponds to _two_ 16-tree levels), peek at all 16
+ * entries at that tree level. If all of them are either int_nodes or
+ * subtree entries, then there are likely plenty of notes below this
+ * level, so we return an incremented fanout.
+ */
+ unsigned int i;
+ if ((n % 2) || (n > 2 * fanout))
+ return fanout;
+ for (i = 0; i < 16; i++) {
+ switch (GET_PTR_TYPE(tree->a[i])) {
+ case PTR_TYPE_SUBTREE:
+ case PTR_TYPE_INTERNAL:
+ continue;
+ default:
+ return fanout;
+ }
+ }
+ return fanout + 1;
+}
+
+static void construct_path_with_fanout(const unsigned char *sha1,
+ unsigned char fanout, char *path)
+{
+ unsigned int i = 0, j = 0;
+ const char *hex_sha1 = sha1_to_hex(sha1);
+ assert(fanout < 20);
+ while (fanout) {
+ path[i++] = hex_sha1[j++];
+ path[i++] = hex_sha1[j++];
+ path[i++] = '/';
+ fanout--;
+ }
+ strcpy(path + i, hex_sha1 + j);
+}
+
+static int for_each_note_helper(struct int_node *tree, unsigned char n,
+ unsigned char fanout, int flags, each_note_fn fn,
+ void *cb_data)
+{
+ unsigned int i;
+ void *p;
+ int ret = 0;
+ struct leaf_node *l;
+ static char path[40 + 19 + 1]; /* hex SHA1 + 19 * '/' + NUL */
+
+ fanout = determine_fanout(tree, n, fanout);
+ for (i = 0; i < 16; i++) {
+redo:
+ p = tree->a[i];
+ switch (GET_PTR_TYPE(p)) {
+ case PTR_TYPE_INTERNAL:
+ /* recurse into int_node */
+ ret = for_each_note_helper(CLR_PTR_TYPE(p), n + 1,
+ fanout, flags, fn, cb_data);
+ break;
+ case PTR_TYPE_SUBTREE:
+ l = (struct leaf_node *) CLR_PTR_TYPE(p);
+ /*
+ * Subtree entries in the note tree represent parts of
+ * the note tree that have not yet been explored. There
+ * is a direct relationship between subtree entries at
+ * level 'n' in the tree, and the 'fanout' variable:
+ * Subtree entries at level 'n <= 2 * fanout' should be
+ * preserved, since they correspond exactly to a fanout
+ * directory in the on-disk structure. However, subtree
+ * entries at level 'n > 2 * fanout' should NOT be
+ * preserved, but rather consolidated into the above
+ * notes tree level. We achieve this by unconditionally
+ * unpacking subtree entries that exist below the
+ * threshold level at 'n = 2 * fanout'.
+ */
+ if (n <= 2 * fanout &&
+ flags & FOR_EACH_NOTE_YIELD_SUBTREES) {
+ /* invoke callback with subtree */
+ unsigned int path_len =
+ l->key_sha1[19] * 2 + fanout;
+ assert(path_len < 40 + 19);
+ construct_path_with_fanout(l->key_sha1, fanout,
+ path);
+ /* Create trailing slash, if needed */
+ if (path[path_len - 1] != '/')
+ path[path_len++] = '/';
+ path[path_len] = '\0';
+ ret = fn(l->key_sha1, l->val_sha1, path,
+ cb_data);
+ }
+ if (n > fanout * 2 ||
+ !(flags & FOR_EACH_NOTE_DONT_UNPACK_SUBTREES)) {
+ /* unpack subtree and resume traversal */
+ tree->a[i] = NULL;
+ load_subtree(l, tree, n);
+ free(l);
+ goto redo;
+ }
+ break;
+ case PTR_TYPE_NOTE:
+ l = (struct leaf_node *) CLR_PTR_TYPE(p);
+ construct_path_with_fanout(l->key_sha1, fanout, path);
+ ret = fn(l->key_sha1, l->val_sha1, path, cb_data);
+ break;
+ }
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
+struct tree_write_stack {
+ struct tree_write_stack *next;
+ struct strbuf buf;
+ char path[2]; /* path to subtree in next, if any */
+};
+
+static inline int matches_tree_write_stack(struct tree_write_stack *tws,
+ const char *full_path)
+{
+ return full_path[0] == tws->path[0] &&
+ full_path[1] == tws->path[1] &&
+ full_path[2] == '/';
+}
+
+static void write_tree_entry(struct strbuf *buf, unsigned int mode,
+ const char *path, unsigned int path_len, const
+ unsigned char *sha1)
+{
+ strbuf_addf(buf, "%06o %.*s%c", mode, path_len, path, '\0');
+ strbuf_add(buf, sha1, 20);
+}
+
+static void tree_write_stack_init_subtree(struct tree_write_stack *tws,
+ const char *path)
+{
+ struct tree_write_stack *n;
+ assert(!tws->next);
+ assert(tws->path[0] == '\0' && tws->path[1] == '\0');
+ n = (struct tree_write_stack *)
+ xmalloc(sizeof(struct tree_write_stack));
+ n->next = NULL;
+ strbuf_init(&n->buf, 256 * (32 + 40)); /* assume 256 entries per tree */
+ n->path[0] = n->path[1] = '\0';
+ tws->next = n;
+ tws->path[0] = path[0];
+ tws->path[1] = path[1];
+}
+
+static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
+{
+ int ret;
+ struct tree_write_stack *n = tws->next;
+ unsigned char s[20];
+ if (n) {
+ ret = tree_write_stack_finish_subtree(n);
+ if (ret)
+ return ret;
+ ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, s);
+ if (ret)
+ return ret;
+ strbuf_release(&n->buf);
+ free(n);
+ tws->next = NULL;
+ write_tree_entry(&tws->buf, 040000, tws->path, 2, s);
+ tws->path[0] = tws->path[1] = '\0';
+ }
+ return 0;
+}
+
+static int write_each_note_helper(struct tree_write_stack *tws,
+ const char *path, unsigned int mode,
+ const unsigned char *sha1)
+{
+ size_t path_len = strlen(path);
+ unsigned int n = 0;
+ int ret;
+
+ /* Determine common part of tree write stack */
+ while (tws && 3 * n < path_len &&
+ matches_tree_write_stack(tws, path + 3 * n)) {
+ n++;
+ tws = tws->next;
+ }
+
+ /* tws point to last matching tree_write_stack entry */
+ ret = tree_write_stack_finish_subtree(tws);
+ if (ret)
+ return ret;
+
+ /* Start subtrees needed to satisfy path */
+ while (3 * n + 2 < path_len && path[3 * n + 2] == '/') {
+ tree_write_stack_init_subtree(tws, path + 3 * n);
+ n++;
+ tws = tws->next;
+ }
+
+ /* There should be no more directory components in the given path */
+ assert(memchr(path + 3 * n, '/', path_len - (3 * n)) == NULL);
+
+ /* Finally add given entry to the current tree object */
+ write_tree_entry(&tws->buf, mode, path + 3 * n, path_len - (3 * n),
+ sha1);
+
+ return 0;
+}
+
+struct write_each_note_data {
+ struct tree_write_stack *root;
+};
+
+static int write_each_note(const unsigned char *object_sha1,
+ const unsigned char *note_sha1, char *note_path,
+ void *cb_data)
+{
+ struct write_each_note_data *d =
+ (struct write_each_note_data *) cb_data;
+ size_t note_path_len = strlen(note_path);
+ unsigned int mode = 0100644;
+
+ if (note_path[note_path_len - 1] == '/') {
+ /* subtree entry */
+ note_path_len--;
+ note_path[note_path_len] = '\0';
+ mode = 040000;
+ }
+ assert(note_path_len <= 40 + 19);
+
+ return write_each_note_helper(d->root, note_path, mode, note_sha1);
+}
+
+void init_notes(struct notes_tree *t, const char *notes_ref, int flags)
{
unsigned char sha1[20], object_sha1[20];
unsigned mode;
struct leaf_node root_tree;
- assert(!initialized);
- initialized = 1;
+ if (!t)
+ t = &default_notes_tree;
+ assert(!t->initialized);
if (!notes_ref)
notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
if (!notes_ref)
notes_ref = GIT_NOTES_DEFAULT_REF;
+ t->root = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
+ t->ref = notes_ref ? xstrdup(notes_ref) : NULL;
+ t->initialized = 1;
+
if (flags & NOTES_INIT_EMPTY || !notes_ref ||
read_ref(notes_ref, object_sha1))
return;
hashclr(root_tree.key_sha1);
hashcpy(root_tree.val_sha1, sha1);
- load_subtree(&root_tree, &root_node, 0);
+ load_subtree(&root_tree, t->root, 0);
}
-void add_note(const unsigned char *object_sha1, const unsigned char *note_sha1)
+void add_note(struct notes_tree *t, const unsigned char *object_sha1,
+ const unsigned char *note_sha1)
{
struct leaf_node *l;
- assert(initialized);
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
l = (struct leaf_node *) xmalloc(sizeof(struct leaf_node));
hashcpy(l->key_sha1, object_sha1);
hashcpy(l->val_sha1, note_sha1);
- note_tree_insert(&root_node, 0, l, PTR_TYPE_NOTE);
+ note_tree_insert(t->root, 0, l, PTR_TYPE_NOTE);
}
-void remove_note(const unsigned char *object_sha1)
+void remove_note(struct notes_tree *t, const unsigned char *object_sha1)
{
struct leaf_node l;
- assert(initialized);
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
hashcpy(l.key_sha1, object_sha1);
hashclr(l.val_sha1);
- return note_tree_remove(&root_node, 0, &l);
+ return note_tree_remove(t, t->root, 0, &l);
}
-static unsigned char *lookup_notes(const unsigned char *object_sha1)
+const unsigned char *get_note(struct notes_tree *t,
+ const unsigned char *object_sha1)
{
- struct leaf_node *found = note_tree_find(&root_node, 0, object_sha1);
- if (found)
- return found->val_sha1;
- return NULL;
+ struct leaf_node *found;
+
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
+ found = note_tree_find(t->root, 0, object_sha1);
+ return found ? found->val_sha1 : NULL;
+}
+
+int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
+ void *cb_data)
+{
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
+ return for_each_note_helper(t->root, 0, 0, flags, fn, cb_data);
+}
+
+int write_notes_tree(struct notes_tree *t, unsigned char *result)
+{
+ struct tree_write_stack root;
+ struct write_each_note_data cb_data;
+ int ret;
+
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
+
+ /* Prepare for traversal of current notes tree */
+ root.next = NULL; /* last forward entry in list is grounded */
+ strbuf_init(&root.buf, 256 * (32 + 40)); /* assume 256 entries */
+ root.path[0] = root.path[1] = '\0';
+ cb_data.root = &root;
+
+ /* Write tree objects representing current notes tree */
+ ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
+ FOR_EACH_NOTE_YIELD_SUBTREES,
+ write_each_note, &cb_data) ||
+ tree_write_stack_finish_subtree(&root) ||
+ write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
+ strbuf_release(&root.buf);
+ return ret;
}
-void free_notes(void)
+void free_notes(struct notes_tree *t)
{
- note_tree_free(&root_node);
- memset(&root_node, 0, sizeof(struct int_node));
- initialized = 0;
+ if (!t)
+ t = &default_notes_tree;
+ if (t->root)
+ note_tree_free(t->root);
+ free(t->root);
+ free(t->ref);
+ memset(t, 0, sizeof(struct notes_tree));
}
-void format_note(const unsigned char *object_sha1, struct strbuf *sb,
- const char *output_encoding, int flags)
+void format_note(struct notes_tree *t, const unsigned char *object_sha1,
+ struct strbuf *sb, const char *output_encoding, int flags)
{
static const char utf8[] = "utf-8";
- unsigned char *sha1;
+ const unsigned char *sha1;
char *msg, *msg_p;
unsigned long linelen, msglen;
enum object_type type;
- if (!initialized)
- init_notes(NULL, 0);
+ if (!t)
+ t = &default_notes_tree;
+ if (!t->initialized)
+ init_notes(t, NULL, 0);
- sha1 = lookup_notes(object_sha1);
+ sha1 = get_note(t, object_sha1);
if (!sha1)
return;
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