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