notes.h

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