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