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-rw-r--r--notes.c429
1 files changed, 429 insertions, 0 deletions
diff --git a/notes.c b/notes.c
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index 0000000..50a4672
--- /dev/null
+++ b/notes.c
@@ -0,0 +1,429 @@
+#include "cache.h"
+#include "commit.h"
+#include "notes.h"
+#include "refs.h"
+#include "utf8.h"
+#include "strbuf.h"
+#include "tree-walk.h"
+
+/*
+ * Use a non-balancing simple 16-tree structure with struct int_node as
+ * internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
+ * 16-array of pointers to its children.
+ * The bottom 2 bits of each pointer is used to identify the pointer type
+ * - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
+ * - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
+ * - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
+ * - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
+ *
+ * The root node is a statically allocated struct int_node.
+ */
+struct int_node {
+ void *a[16];
+};
+
+/*
+ * Leaf nodes come in two variants, note entries and subtree entries,
+ * distinguished by the LSb of the leaf node pointer (see above).
+ * As a note entry, the key is the SHA1 of the referenced commit, and the
+ * value is the SHA1 of the note object.
+ * As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
+ * referenced commit, using the last byte of the key to store the length of
+ * the prefix. The value is the SHA1 of the tree object containing the notes
+ * subtree.
+ */
+struct leaf_node {
+ unsigned char key_sha1[20];
+ unsigned char val_sha1[20];
+};
+
+#define PTR_TYPE_NULL 0
+#define PTR_TYPE_INTERNAL 1
+#define PTR_TYPE_NOTE 2
+#define PTR_TYPE_SUBTREE 3
+
+#define GET_PTR_TYPE(ptr) ((uintptr_t) (ptr) & 3)
+#define CLR_PTR_TYPE(ptr) ((void *) ((uintptr_t) (ptr) & ~3))
+#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))
+
+#define GET_NIBBLE(n, sha1) (((sha1[n >> 1]) >> ((~n & 0x01) << 2)) & 0x0f)
+
+#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;
+
+static void load_subtree(struct leaf_node *subtree, struct int_node *node,
+ unsigned int n);
+
+/*
+ * Search the tree until the appropriate location for the given key is found:
+ * 1. Start at the root node, with n = 0
+ * 2. If a[0] at the current level is a matching subtree entry, unpack that
+ * subtree entry and remove it; restart search at the current level.
+ * 3. Use the nth nibble of the key as an index into a:
+ * - If a[n] is an int_node, recurse from #2 into that node and increment n
+ * - If a matching subtree entry, unpack that subtree entry (and remove it);
+ * restart search at the current level.
+ * - Otherwise, we have found one of the following:
+ * - a subtree entry which does not match the key
+ * - a note entry which may or may not match the key
+ * - an unused leaf node (NULL)
+ * In any case, set *tree and *n, and return pointer to the tree location.
+ */
+static void **note_tree_search(struct int_node **tree,
+ unsigned char *n, const unsigned char *key_sha1)
+{
+ struct leaf_node *l;
+ unsigned char i;
+ void *p = (*tree)->a[0];
+
+ if (GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE) {
+ l = (struct leaf_node *) CLR_PTR_TYPE(p);
+ if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
+ /* unpack tree and resume search */
+ (*tree)->a[0] = NULL;
+ load_subtree(l, *tree, *n);
+ free(l);
+ return note_tree_search(tree, n, key_sha1);
+ }
+ }
+
+ i = GET_NIBBLE(*n, key_sha1);
+ p = (*tree)->a[i];
+ switch(GET_PTR_TYPE(p)) {
+ case PTR_TYPE_INTERNAL:
+ *tree = CLR_PTR_TYPE(p);
+ (*n)++;
+ return note_tree_search(tree, n, key_sha1);
+ case PTR_TYPE_SUBTREE:
+ l = (struct leaf_node *) CLR_PTR_TYPE(p);
+ if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
+ /* unpack tree and resume search */
+ (*tree)->a[i] = NULL;
+ load_subtree(l, *tree, *n);
+ free(l);
+ return note_tree_search(tree, n, key_sha1);
+ }
+ /* fall through */
+ default:
+ return &((*tree)->a[i]);
+ }
+}
+
+/*
+ * To find a leaf_node:
+ * Search to the tree location appropriate for the given key:
+ * If a note entry with matching key, return the note entry, else return NULL.
+ */
+static struct leaf_node *note_tree_find(struct int_node *tree, unsigned char n,
+ const unsigned char *key_sha1)
+{
+ void **p = note_tree_search(&tree, &n, key_sha1);
+ if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
+ struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
+ if (!hashcmp(key_sha1, l->key_sha1))
+ return l;
+ }
+ return NULL;
+}
+
+/* Create a new blob object by concatenating the two given blob objects */
+static int concatenate_notes(unsigned char *cur_sha1,
+ const unsigned char *new_sha1)
+{
+ char *cur_msg, *new_msg, *buf;
+ unsigned long cur_len, new_len, buf_len;
+ enum object_type cur_type, new_type;
+ int ret;
+
+ /* read in both note blob objects */
+ new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
+ if (!new_msg || !new_len || new_type != OBJ_BLOB) {
+ free(new_msg);
+ return 0;
+ }
+ cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
+ if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
+ free(cur_msg);
+ free(new_msg);
+ hashcpy(cur_sha1, new_sha1);
+ return 0;
+ }
+
+ /* we will separate the notes by a newline anyway */
+ if (cur_msg[cur_len - 1] == '\n')
+ cur_len--;
+
+ /* concatenate cur_msg and new_msg into buf */
+ buf_len = cur_len + 1 + new_len;
+ buf = (char *) xmalloc(buf_len);
+ memcpy(buf, cur_msg, cur_len);
+ buf[cur_len] = '\n';
+ memcpy(buf + cur_len + 1, new_msg, new_len);
+
+ free(cur_msg);
+ free(new_msg);
+
+ /* create a new blob object from buf */
+ ret = write_sha1_file(buf, buf_len, "blob", cur_sha1);
+ free(buf);
+ return ret;
+}
+
+/*
+ * To insert a leaf_node:
+ * Search to the tree location appropriate for the given leaf_node's key:
+ * - If location is unused (NULL), store the tweaked pointer directly there
+ * - If location holds a note entry that matches the note-to-be-inserted, then
+ * concatenate the two notes.
+ * - If location holds a note entry that matches the subtree-to-be-inserted,
+ * then unpack the subtree-to-be-inserted into the location.
+ * - If location holds a matching subtree entry, unpack the subtree at that
+ * location, and restart the insert operation from that level.
+ * - Else, create a new int_node, holding both the node-at-location and the
+ * node-to-be-inserted, and store the new int_node into the location.
+ */
+static void note_tree_insert(struct int_node *tree, unsigned char n,
+ struct leaf_node *entry, unsigned char type)
+{
+ struct int_node *new_node;
+ struct leaf_node *l;
+ void **p = note_tree_search(&tree, &n, entry->key_sha1);
+
+ assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
+ l = (struct leaf_node *) CLR_PTR_TYPE(*p);
+ switch(GET_PTR_TYPE(*p)) {
+ case PTR_TYPE_NULL:
+ assert(!*p);
+ *p = SET_PTR_TYPE(entry, type);
+ return;
+ case PTR_TYPE_NOTE:
+ switch (type) {
+ case PTR_TYPE_NOTE:
+ if (!hashcmp(l->key_sha1, entry->key_sha1)) {
+ /* skip concatenation if l == entry */
+ if (!hashcmp(l->val_sha1, entry->val_sha1))
+ return;
+
+ if (concatenate_notes(l->val_sha1,
+ entry->val_sha1))
+ die("failed to concatenate note %s "
+ "into note %s for commit %s",
+ sha1_to_hex(entry->val_sha1),
+ sha1_to_hex(l->val_sha1),
+ sha1_to_hex(l->key_sha1));
+ free(entry);
+ return;
+ }
+ break;
+ case PTR_TYPE_SUBTREE:
+ if (!SUBTREE_SHA1_PREFIXCMP(l->key_sha1,
+ entry->key_sha1)) {
+ /* unpack 'entry' */
+ load_subtree(entry, tree, n);
+ free(entry);
+ return;
+ }
+ break;
+ }
+ break;
+ case PTR_TYPE_SUBTREE:
+ if (!SUBTREE_SHA1_PREFIXCMP(entry->key_sha1, l->key_sha1)) {
+ /* unpack 'l' and restart insert */
+ *p = NULL;
+ load_subtree(l, tree, n);
+ free(l);
+ note_tree_insert(tree, n, entry, type);
+ return;
+ }
+ break;
+ }
+
+ /* non-matching leaf_node */
+ assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
+ GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
+ new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
+ note_tree_insert(new_node, n + 1, l, GET_PTR_TYPE(*p));
+ *p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
+ note_tree_insert(new_node, n + 1, entry, type);
+}
+
+/* Free the entire notes data contained in the given tree */
+static void note_tree_free(struct int_node *tree)
+{
+ unsigned int i;
+ for (i = 0; i < 16; i++) {
+ void *p = tree->a[i];
+ switch(GET_PTR_TYPE(p)) {
+ case PTR_TYPE_INTERNAL:
+ note_tree_free(CLR_PTR_TYPE(p));
+ /* fall through */
+ case PTR_TYPE_NOTE:
+ case PTR_TYPE_SUBTREE:
+ free(CLR_PTR_TYPE(p));
+ }
+ }
+}
+
+/*
+ * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
+ * - hex - Partial SHA1 segment in ASCII hex format
+ * - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
+ * - sha1 - Partial SHA1 value is written here
+ * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
+ * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format).
+ * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
+ * Pads sha1 with NULs up to sha1_len (not included in returned length).
+ */
+static int get_sha1_hex_segment(const char *hex, unsigned int hex_len,
+ unsigned char *sha1, unsigned int sha1_len)
+{
+ unsigned int i, len = hex_len >> 1;
+ if (hex_len % 2 != 0 || len > sha1_len)
+ return -1;
+ for (i = 0; i < len; i++) {
+ unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
+ if (val & ~0xff)
+ return -1;
+ *sha1++ = val;
+ hex += 2;
+ }
+ for (; i < sha1_len; i++)
+ *sha1++ = 0;
+ return len;
+}
+
+static void load_subtree(struct leaf_node *subtree, struct int_node *node,
+ unsigned int n)
+{
+ unsigned char commit_sha1[20];
+ unsigned int prefix_len;
+ void *buf;
+ struct tree_desc desc;
+ struct name_entry entry;
+
+ buf = fill_tree_descriptor(&desc, subtree->val_sha1);
+ if (!buf)
+ die("Could not read %s for notes-index",
+ sha1_to_hex(subtree->val_sha1));
+
+ prefix_len = subtree->key_sha1[19];
+ assert(prefix_len * 2 >= n);
+ memcpy(commit_sha1, subtree->key_sha1, prefix_len);
+ while (tree_entry(&desc, &entry)) {
+ int len = get_sha1_hex_segment(entry.path, strlen(entry.path),
+ commit_sha1 + prefix_len, 20 - prefix_len);
+ if (len < 0)
+ continue; /* entry.path is not a SHA1 sum. Skip */
+ len += prefix_len;
+
+ /*
+ * If commit SHA1 is complete (len == 20), assume note object
+ * If commit SHA1 is incomplete (len < 20), assume note subtree
+ */
+ if (len <= 20) {
+ unsigned char type = PTR_TYPE_NOTE;
+ struct leaf_node *l = (struct leaf_node *)
+ xcalloc(sizeof(struct leaf_node), 1);
+ hashcpy(l->key_sha1, commit_sha1);
+ hashcpy(l->val_sha1, entry.sha1);
+ if (len < 20) {
+ l->key_sha1[19] = (unsigned char) len;
+ type = PTR_TYPE_SUBTREE;
+ }
+ note_tree_insert(node, n, l, type);
+ }
+ }
+ free(buf);
+}
+
+static void initialize_notes(const char *notes_ref_name)
+{
+ unsigned char sha1[20], commit_sha1[20];
+ unsigned mode;
+ struct leaf_node root_tree;
+
+ if (!notes_ref_name || read_ref(notes_ref_name, commit_sha1) ||
+ get_tree_entry(commit_sha1, "", sha1, &mode))
+ return;
+
+ hashclr(root_tree.key_sha1);
+ hashcpy(root_tree.val_sha1, sha1);
+ load_subtree(&root_tree, &root_node, 0);
+}
+
+static unsigned char *lookup_notes(const unsigned char *commit_sha1)
+{
+ struct leaf_node *found = note_tree_find(&root_node, 0, commit_sha1);
+ if (found)
+ return found->val_sha1;
+ return NULL;
+}
+
+void free_notes(void)
+{
+ note_tree_free(&root_node);
+ memset(&root_node, 0, sizeof(struct int_node));
+ initialized = 0;
+}
+
+void get_commit_notes(const struct commit *commit, struct strbuf *sb,
+ const char *output_encoding, int flags)
+{
+ static const char utf8[] = "utf-8";
+ unsigned char *sha1;
+ char *msg, *msg_p;
+ unsigned long linelen, msglen;
+ enum object_type type;
+
+ if (!initialized) {
+ const char *env = getenv(GIT_NOTES_REF_ENVIRONMENT);
+ if (env)
+ notes_ref_name = getenv(GIT_NOTES_REF_ENVIRONMENT);
+ else if (!notes_ref_name)
+ notes_ref_name = GIT_NOTES_DEFAULT_REF;
+ initialize_notes(notes_ref_name);
+ initialized = 1;
+ }
+
+ sha1 = lookup_notes(commit->object.sha1);
+ if (!sha1)
+ return;
+
+ if (!(msg = read_sha1_file(sha1, &type, &msglen)) || !msglen ||
+ type != OBJ_BLOB) {
+ free(msg);
+ return;
+ }
+
+ if (output_encoding && *output_encoding &&
+ strcmp(utf8, output_encoding)) {
+ char *reencoded = reencode_string(msg, output_encoding, utf8);
+ if (reencoded) {
+ free(msg);
+ msg = reencoded;
+ msglen = strlen(msg);
+ }
+ }
+
+ /* we will end the annotation by a newline anyway */
+ if (msglen && msg[msglen - 1] == '\n')
+ msglen--;
+
+ if (flags & NOTES_SHOW_HEADER)
+ strbuf_addstr(sb, "\nNotes:\n");
+
+ for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
+ linelen = strchrnul(msg_p, '\n') - msg_p;
+
+ if (flags & NOTES_INDENT)
+ strbuf_addstr(sb, " ");
+ strbuf_add(sb, msg_p, linelen);
+ strbuf_addch(sb, '\n');
+ }
+
+ free(msg);
+}