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