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