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 object_ids -- 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 oid into the first argument (cur_oid). A non-zero return
  15  * value indicates failure.
  16  *
  17  * The two given object_ids shall both be non-NULL and different from each
  18  * other. Either of them (but not both) may be == null_oid, which indicates an
  19  * empty/non-existent note. If the resulting oid (cur_oid) is == null_oid,
  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)(struct object_id *cur_oid,
  27                                 const struct object_id *new_oid);
  28
  29 /* Common notes combinators */
  30 int combine_notes_concatenate(struct object_id *cur_oid,
  31                               const struct object_id *new_oid);
  32 int combine_notes_overwrite(struct object_id *cur_oid,
  33                             const struct object_id *new_oid);
  34 int combine_notes_ignore(struct object_id *cur_oid,
  35                          const struct object_id *new_oid);
  36 int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
  37                                 const struct object_id *new_oid);
  38
  39 /*
  40  * Notes tree object
  41  *
  42  * Encapsulates the internal notes tree structure associated with a notes ref.
  43  * Whenever a struct notes_tree pointer is required below, you may pass NULL in
  44  * order to use the default/internal notes tree. E.g. you only need to pass a
  45  * non-NULL value if you need to refer to several different notes trees
  46  * simultaneously.
  47  */
  48 extern struct notes_tree {
  49         struct int_node *root;
  50         struct non_note *first_non_note, *prev_non_note;
  51         char *ref;
  52         char *update_ref;
  53         combine_notes_fn combine_notes;
  54         int initialized;
  55         int dirty;
  56 } default_notes_tree;
  57
  58 /*
  59  * Return the default notes ref.
  60  *
  61  * The default notes ref is the notes ref that is used when notes_ref == NULL
  62  * is passed to init_notes().
  63  *
  64  * This the first of the following to be defined:
  65  * 1. The '--ref' option to 'git notes', if given
  66  * 2. The $GIT_NOTES_REF environment variable, if set
  67  * 3. The value of the core.notesRef config variable, if set
  68  * 4. GIT_NOTES_DEFAULT_REF (i.e. "refs/notes/commits")
  69  */
  70 const char *default_notes_ref(void);
  71
  72 /*
  73  * Flags controlling behaviour of notes tree initialization
  74  *
  75  * Default behaviour is to initialize the notes tree from the tree object
  76  * specified by the given (or default) notes ref.
  77  */
  78 #define NOTES_INIT_EMPTY 1
  79
  80 /*
  81  * By default, the notes tree is only readable, and the notes ref can be
  82  * any treeish. The notes tree can however be made writable with this flag,
  83  * in which case only strict ref names can be used.
  84  */
  85 #define NOTES_INIT_WRITABLE 2
  86
  87 /*
  88  * Initialize the given notes_tree with the notes tree structure at the given
  89  * ref. If given ref is NULL, the value of the $GIT_NOTES_REF environment
  90  * variable is used, and if that is missing, the default notes ref is used
  91  * ("refs/notes/commits").
  92  *
  93  * If you need to re-initialize a notes_tree structure (e.g. when switching from
  94  * one notes ref to another), you must first de-initialize the notes_tree
  95  * structure by calling free_notes(struct notes_tree *).
  96  *
  97  * If you pass t == NULL, the default internal notes_tree will be initialized.
  98  *
  99  * The combine_notes function that is passed becomes the default combine_notes
 100  * function for the given notes_tree. If NULL is passed, the default
 101  * combine_notes function is combine_notes_concatenate().
 102  *
 103  * Precondition: The notes_tree structure is zeroed (this can be achieved with
 104  * memset(t, 0, sizeof(struct notes_tree)))
 105  */
 106 void init_notes(struct notes_tree *t, const char *notes_ref,
 107                 combine_notes_fn combine_notes, int flags);
 108
 109 /*
 110  * Add the given note object to the given notes_tree structure
 111  *
 112  * If there already exists a note for the given object_sha1, the given
 113  * combine_notes function is invoked to break the tie. If not given (i.e.
 114  * combine_notes == NULL), the default combine_notes function for the given
 115  * notes_tree is used.
 116  *
 117  * Passing note_sha1 == null_sha1 indicates the addition of an
 118  * empty/non-existent note. This is a (potentially expensive) no-op unless
 119  * there already exists a note for the given object_sha1, AND combining that
 120  * note with the empty note (using the given combine_notes function) results
 121  * in a new/changed note.
 122  *
 123  * Returns zero on success; non-zero means combine_notes failed.
 124  *
 125  * IMPORTANT: The changes made by add_note() to the given notes_tree structure
 126  * are not persistent until a subsequent call to write_notes_tree() returns
 127  * zero.
 128  */
 129 int add_note(struct notes_tree *t, const struct object_id *object_oid,
 130                 const struct object_id *note_oid, combine_notes_fn combine_notes);
 131
 132 /*
 133  * Remove the given note object from the given notes_tree structure
 134  *
 135  * IMPORTANT: The changes made by remove_note() to the given notes_tree
 136  * structure are not persistent until a subsequent call to write_notes_tree()
 137  * returns zero.
 138  *
 139  * Return 0 if a note was removed; 1 if there was no note to remove.
 140  */
 141 int remove_note(struct notes_tree *t, const unsigned char *object_sha1);
 142
 143 /*
 144  * Get the note object SHA1 containing the note data for the given object
 145  *
 146  * Return NULL if the given object has no notes.
 147  */
 148 const struct object_id *get_note(struct notes_tree *t,
 149                 const struct object_id *object_oid);
 150
 151 /*
 152  * Copy a note from one object to another in the given notes_tree.
 153  *
 154  * Returns 1 if the to_obj already has a note and 'force' is false. Otherwise,
 155  * returns non-zero if 'force' is true, but the given combine_notes function
 156  * failed to combine from_obj's note with to_obj's existing note.
 157  * Returns zero on success.
 158  *
 159  * IMPORTANT: The changes made by copy_note() to the given notes_tree structure
 160  * are not persistent until a subsequent call to write_notes_tree() returns
 161  * zero.
 162  */
 163 int copy_note(struct notes_tree *t,
 164               const struct object_id *from_obj, const struct object_id *to_obj,
 165               int force, combine_notes_fn combine_notes);
 166
 167 /*
 168  * Flags controlling behaviour of for_each_note()
 169  *
 170  * Default behaviour of for_each_note() is to traverse every single note object
 171  * in the given notes tree, unpacking subtree entries along the way.
 172  * The following flags can be used to alter the default behaviour:
 173  *
 174  * - DONT_UNPACK_SUBTREES causes for_each_note() NOT to unpack and recurse into
 175  *   subtree entries while traversing the notes tree. This causes notes within
 176  *   those subtrees NOT to be passed to the callback. Use this flag if you
 177  *   don't want to traverse _all_ notes, but only want to traverse the parts
 178  *   of the notes tree that have already been unpacked (this includes at least
 179  *   all notes that have been added/changed).
 180  *
 181  * - YIELD_SUBTREES causes any subtree entries that are encountered to be
 182  *   passed to the callback, before recursing into them. Subtree entries are
 183  *   not note objects, but represent intermediate directories in the notes
 184  *   tree. When passed to the callback, subtree entries will have a trailing
 185  *   slash in their path, which the callback may use to differentiate between
 186  *   note entries and subtree entries. Note that already-unpacked subtree
 187  *   entries are not part of the notes tree, and will therefore not be yielded.
 188  *   If this flag is used together with DONT_UNPACK_SUBTREES, for_each_note()
 189  *   will yield the subtree entry, but not recurse into it.
 190  */
 191 #define FOR_EACH_NOTE_DONT_UNPACK_SUBTREES 1
 192 #define FOR_EACH_NOTE_YIELD_SUBTREES 2
 193
 194 /*
 195  * Invoke the specified callback function for each note in the given notes_tree
 196  *
 197  * If the callback returns nonzero, the note walk is aborted, and the return
 198  * value from the callback is returned from for_each_note(). Hence, a zero
 199  * return value from for_each_note() indicates that all notes were walked
 200  * successfully.
 201  *
 202  * IMPORTANT: The callback function is NOT allowed to change the notes tree.
 203  * In other words, the following functions can NOT be invoked (on the current
 204  * notes tree) from within the callback:
 205  * - add_note()
 206  * - remove_note()
 207  * - copy_note()
 208  * - free_notes()
 209  */
 210 typedef int each_note_fn(const struct object_id *object_oid,
 211                 const struct object_id *note_oid, char *note_path,
 212                 void *cb_data);
 213 int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
 214                 void *cb_data);
 215
 216 /*
 217  * Write the given notes_tree structure to the object database
 218  *
 219  * Creates a new tree object encapsulating the current state of the given
 220  * notes_tree, and stores its object id into the 'result' argument.
 221  *
 222  * Returns zero on success, non-zero on failure.
 223  *
 224  * IMPORTANT: Changes made to the given notes_tree are not persistent until
 225  * this function has returned zero. Please also remember to create a
 226  * corresponding commit object, and update the appropriate notes ref.
 227  */
 228 int write_notes_tree(struct notes_tree *t, struct object_id *result);
 229
 230 /* Flags controlling the operation of prune */
 231 #define NOTES_PRUNE_VERBOSE 1
 232 #define NOTES_PRUNE_DRYRUN 2
 233 /*
 234  * Remove all notes annotating non-existing objects from the given notes tree
 235  *
 236  * All notes in the given notes_tree that are associated with objects that no
 237  * longer exist in the database, are removed from the notes tree.
 238  *
 239  * IMPORTANT: The changes made by prune_notes() to the given notes_tree
 240  * structure are not persistent until a subsequent call to write_notes_tree()
 241  * returns zero.
 242  */
 243 void prune_notes(struct notes_tree *t, int flags);
 244
 245 /*
 246  * Free (and de-initialize) the given notes_tree structure
 247  *
 248  * IMPORTANT: Changes made to the given notes_tree since the last, successful
 249  * call to write_notes_tree() will be lost.
 250  */
 251 void free_notes(struct notes_tree *t);
 252
 253 struct string_list;
 254
 255 struct display_notes_opt {
 256         int use_default_notes;
 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 struct object_id *object_oid,
 286                           struct strbuf *sb, const char *output_encoding, int raw);
 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, int flags);
 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 /* Expand inplace a note ref like "foo" or "notes/foo" into "refs/notes/foo" */
 308 void expand_notes_ref(struct strbuf *sb);
 309
 310 /*
 311  * Similar to expand_notes_ref, but will check whether the ref can be located
 312  * via get_sha1 first, and only falls back to expand_notes_ref in the case
 313  * where get_sha1 fails.
 314  */
 315 void expand_loose_notes_ref(struct strbuf *sb);
 316
 317 #endif