notes.h

   1 #ifndef NOTES_H
   2 #define NOTES_H
   3
   4 #include "string-list.h"
   5
   6 /*
   7  * Function type for combining two notes annotating the same object.
   8  *
   9  * When adding a new note annotating the same object as an existing note, it is
  10  * up to the caller to decide how to combine the two notes. The decision is
  11  * made by passing in a function of the following form. The function accepts
  12  * two SHA1s -- of the existing note and the new note, respectively. The
  13  * function then combines the notes in whatever way it sees fit, and writes the
  14  * resulting SHA1 into the first SHA1 argument (cur_sha1). A non-zero return
  15  * value indicates failure.
  16  *
  17  * The two given SHA1s shall both be non-NULL and different from each other.
  18  * Either of them (but not both) may be == null_sha1, which indicates an
  19  * empty/non-existent note. If the resulting SHA1 (cur_sha1) is == null_sha1,
  20  * the note will be removed from the notes tree.
  21  *
  22  * The default combine_notes function (you get this when passing NULL) is
  23  * combine_notes_concatenate(), which appends the contents of the new note to
  24  * the contents of the existing note.
  25  */
  26 typedef int (*combine_notes_fn)(unsigned char *cur_sha1, const unsigned char *new_sha1);
  27
  28 /* Common notes combinators */
  29 int combine_notes_concatenate(unsigned char *cur_sha1, const unsigned char *new_sha1);
  30 int combine_notes_overwrite(unsigned char *cur_sha1, const unsigned char *new_sha1);
  31 int combine_notes_ignore(unsigned char *cur_sha1, const unsigned char *new_sha1);
  32 int combine_notes_cat_sort_uniq(unsigned char *cur_sha1, const unsigned char *new_sha1);
  33
  34 /*
  35  * Notes tree object
  36  *
  37  * Encapsulates the internal notes tree structure associated with a notes ref.
  38  * Whenever a struct notes_tree pointer is required below, you may pass NULL in
  39  * order to use the default/internal notes tree. E.g. you only need to pass a
  40  * non-NULL value if you need to refer to several different notes trees
  41  * simultaneously.
  42  */
  43 extern struct notes_tree {
  44         struct int_node *root;
  45         struct non_note *first_non_note, *prev_non_note;
  46         char *ref;
  47         char *update_ref;
  48         combine_notes_fn combine_notes;
  49         int initialized;
  50         int dirty;
  51 } default_notes_tree;
  52
  53 /*
  54  * Return the default notes ref.
  55  *
  56  * The default notes ref is the notes ref that is used when notes_ref == NULL
  57  * is passed to init_notes().
  58  *
  59  * This the first of the following to be defined:
  60  * 1. The '--ref' option to 'git notes', if given
  61  * 2. The $GIT_NOTES_REF environment variable, if set
  62  * 3. The value of the core.notesRef config variable, if set
  63  * 4. GIT_NOTES_DEFAULT_REF (i.e. "refs/notes/commits")
  64  */
  65 const char *default_notes_ref(void);
  66
  67 /*
  68  * Flags controlling behaviour of notes tree initialization
  69  *
  70  * Default behaviour is to initialize the notes tree from the tree object
  71  * specified by the given (or default) notes ref.
  72  */
  73 #define NOTES_INIT_EMPTY 1
  74
  75 /*
  76  * By default, the notes tree is only readable, and the notes ref can be
  77  * any treeish. The notes tree can however be made writable with this flag,
  78  * in which case only strict ref names can be used.
  79  */
  80 #define NOTES_INIT_WRITABLE 2
  81
  82 /*
  83  * Initialize the given notes_tree with the notes tree structure at the given
  84  * ref. If given ref is NULL, the value of the $GIT_NOTES_REF environment
  85  * variable is used, and if that is missing, the default notes ref is used
  86  * ("refs/notes/commits").
  87  *
  88  * If you need to re-initialize a notes_tree structure (e.g. when switching from
  89  * one notes ref to another), you must first de-initialize the notes_tree
  90  * structure by calling free_notes(struct notes_tree *).
  91  *
  92  * If you pass t == NULL, the default internal notes_tree will be initialized.
  93  *
  94  * The combine_notes function that is passed becomes the default combine_notes
  95  * function for the given notes_tree. If NULL is passed, the default
  96  * combine_notes function is combine_notes_concatenate().
  97  *
  98  * Precondition: The notes_tree structure is zeroed (this can be achieved with
  99  * memset(t, 0, sizeof(struct notes_tree)))
 100  */
 101 void init_notes(struct notes_tree *t, const char *notes_ref,
 102                 combine_notes_fn combine_notes, int flags);
 103
 104 /*
 105  * Add the given note object to the given notes_tree structure
 106  *
 107  * If there already exists a note for the given object_sha1, the given
 108  * combine_notes function is invoked to break the tie. If not given (i.e.
 109  * combine_notes == NULL), the default combine_notes function for the given
 110  * notes_tree is used.
 111  *
 112  * Passing note_sha1 == null_sha1 indicates the addition of an
 113  * empty/non-existent note. This is a (potentially expensive) no-op unless
 114  * there already exists a note for the given object_sha1, AND combining that
 115  * note with the empty note (using the given combine_notes function) results
 116  * in a new/changed note.
 117  *
 118  * Returns zero on success; non-zero means combine_notes failed.
 119  *
 120  * IMPORTANT: The changes made by add_note() to the given notes_tree structure
 121  * are not persistent until a subsequent call to write_notes_tree() returns
 122  * zero.
 123  */
 124 int add_note(struct notes_tree *t, const unsigned char *object_sha1,
 125                 const unsigned char *note_sha1, combine_notes_fn combine_notes);
 126
 127 /*
 128  * Remove the given note object from the given notes_tree structure
 129  *
 130  * IMPORTANT: The changes made by remove_note() to the given notes_tree
 131  * structure are not persistent until a subsequent call to write_notes_tree()
 132  * returns zero.
 133  *
 134  * Return 0 if a note was removed; 1 if there was no note to remove.
 135  */
 136 int remove_note(struct notes_tree *t, const unsigned char *object_sha1);
 137
 138 /*
 139  * Get the note object SHA1 containing the note data for the given object
 140  *
 141  * Return NULL if the given object has no notes.
 142  */
 143 const unsigned char *get_note(struct notes_tree *t,
 144                 const unsigned char *object_sha1);
 145
 146 /*
 147  * Copy a note from one object to another in the given notes_tree.
 148  *
 149  * Returns 1 if the to_obj already has a note and 'force' is false. Otherwise,
 150  * returns non-zero if 'force' is true, but the given combine_notes function
 151  * failed to combine from_obj's note with to_obj's existing note.
 152  * Returns zero on success.
 153  *
 154  * IMPORTANT: The changes made by copy_note() to the given notes_tree structure
 155  * are not persistent until a subsequent call to write_notes_tree() returns
 156  * zero.
 157  */
 158 int copy_note(struct notes_tree *t,
 159               const unsigned char *from_obj, const unsigned char *to_obj,
 160               int force, combine_notes_fn combine_notes);
 161
 162 /*
 163  * Flags controlling behaviour of for_each_note()
 164  *
 165  * Default behaviour of for_each_note() is to traverse every single note object
 166  * in the given notes tree, unpacking subtree entries along the way.
 167  * The following flags can be used to alter the default behaviour:
 168  *
 169  * - DONT_UNPACK_SUBTREES causes for_each_note() NOT to unpack and recurse into
 170  *   subtree entries while traversing the notes tree. This causes notes within
 171  *   those subtrees NOT to be passed to the callback. Use this flag if you
 172  *   don't want to traverse _all_ notes, but only want to traverse the parts
 173  *   of the notes tree that have already been unpacked (this includes at least
 174  *   all notes that have been added/changed).
 175  *
 176  * - YIELD_SUBTREES causes any subtree entries that are encountered to be
 177  *   passed to the callback, before recursing into them. Subtree entries are
 178  *   not note objects, but represent intermediate directories in the notes
 179  *   tree. When passed to the callback, subtree entries will have a trailing
 180  *   slash in their path, which the callback may use to differentiate between
 181  *   note entries and subtree entries. Note that already-unpacked subtree
 182  *   entries are not part of the notes tree, and will therefore not be yielded.
 183  *   If this flag is used together with DONT_UNPACK_SUBTREES, for_each_note()
 184  *   will yield the subtree entry, but not recurse into it.
 185  */
 186 #define FOR_EACH_NOTE_DONT_UNPACK_SUBTREES 1
 187 #define FOR_EACH_NOTE_YIELD_SUBTREES 2
 188
 189 /*
 190  * Invoke the specified callback function for each note in the given notes_tree
 191  *
 192  * If the callback returns nonzero, the note walk is aborted, and the return
 193  * value from the callback is returned from for_each_note(). Hence, a zero
 194  * return value from for_each_note() indicates that all notes were walked
 195  * successfully.
 196  *
 197  * IMPORTANT: The callback function is NOT allowed to change the notes tree.
 198  * In other words, the following functions can NOT be invoked (on the current
 199  * notes tree) from within the callback:
 200  * - add_note()
 201  * - remove_note()
 202  * - copy_note()
 203  * - free_notes()
 204  */
 205 typedef int each_note_fn(const unsigned char *object_sha1,
 206                 const unsigned char *note_sha1, char *note_path,
 207                 void *cb_data);
 208 int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
 209                 void *cb_data);
 210
 211 /*
 212  * Write the given notes_tree structure to the object database
 213  *
 214  * Creates a new tree object encapsulating the current state of the given
 215  * notes_tree, and stores its SHA1 into the 'result' argument.
 216  *
 217  * Returns zero on success, non-zero on failure.
 218  *
 219  * IMPORTANT: Changes made to the given notes_tree are not persistent until
 220  * this function has returned zero. Please also remember to create a
 221  * corresponding commit object, and update the appropriate notes ref.
 222  */
 223 int write_notes_tree(struct notes_tree *t, unsigned char *result);
 224
 225 /* Flags controlling the operation of prune */
 226 #define NOTES_PRUNE_VERBOSE 1
 227 #define NOTES_PRUNE_DRYRUN 2
 228 /*
 229  * Remove all notes annotating non-existing objects from the given notes tree
 230  *
 231  * All notes in the given notes_tree that are associated with objects that no
 232  * longer exist in the database, are removed from the notes tree.
 233  *
 234  * IMPORTANT: The changes made by prune_notes() to the given notes_tree
 235  * structure are not persistent until a subsequent call to write_notes_tree()
 236  * returns zero.
 237  */
 238 void prune_notes(struct notes_tree *t, int flags);
 239
 240 /*
 241  * Free (and de-initialize) the given notes_tree structure
 242  *
 243  * IMPORTANT: Changes made to the given notes_tree since the last, successful
 244  * call to write_notes_tree() will be lost.
 245  */
 246 void free_notes(struct notes_tree *t);
 247
 248 struct string_list;
 249
 250 struct display_notes_opt {
 251         int use_default_notes;
 252         struct string_list extra_notes_refs;
 253 };
 254
 255 /*
 256  * Load the notes machinery for displaying several notes trees.
 257  *
 258  * If 'opt' is not NULL, then it specifies additional settings for the
 259  * displaying:
 260  *
 261  * - suppress_default_notes indicates that the notes from
 262  *   core.notesRef and notes.displayRef should not be loaded.
 263  *
 264  * - extra_notes_refs may contain a list of globs (in the same style
 265  *   as notes.displayRef) where notes should be loaded from.
 266  */
 267 void init_display_notes(struct display_notes_opt *opt);
 268
 269 /*
 270  * Append notes for the given 'object_sha1' from all trees set up by
 271  * init_display_notes() to 'sb'.  The 'flags' are a bitwise
 272  * combination of
 273  *
 274  * - NOTES_SHOW_HEADER: add a 'Notes (refname):' header
 275  *
 276  * - NOTES_INDENT: indent the notes by 4 places
 277  *
 278  * You *must* call init_display_notes() before using this function.
 279  */
 280 void format_display_notes(const unsigned char *object_sha1,
 281                           struct strbuf *sb, const char *output_encoding, int raw);
 282
 283 /*
 284  * Load the notes tree from each ref listed in 'refs'.  The output is
 285  * an array of notes_tree*, terminated by a NULL.
 286  */
 287 struct notes_tree **load_notes_trees(struct string_list *refs, int flags);
 288
 289 /*
 290  * Add all refs that match 'glob' to the 'list'.
 291  */
 292 void string_list_add_refs_by_glob(struct string_list *list, const char *glob);
 293
 294 /*
 295  * Add all refs from a colon-separated glob list 'globs' to the end of
 296  * 'list'.  Empty components are ignored.  This helper is used to
 297  * parse GIT_NOTES_DISPLAY_REF style environment variables.
 298  */
 299 void string_list_add_refs_from_colon_sep(struct string_list *list,
 300                                          const char *globs);
 301
 302 /* Expand inplace a note ref like "foo" or "notes/foo" into "refs/notes/foo" */
 303 void expand_notes_ref(struct strbuf *sb);
 304
 305 /*
 306  * Similar to expand_notes_ref, but will check whether the ref can be located
 307  * via get_sha1 first, and only falls back to expand_notes_ref in the case
 308  * where get_sha1 fails.
 309  */
 310 void expand_loose_notes_ref(struct strbuf *sb);
 311
 312 #endif