notes.h

   1 #ifndef NOTES_H
   2 #define NOTES_H
   3
   4 /*
   5  * Notes tree object
   6  *
   7  * Encapsulates the internal notes tree structure associated with a notes ref.
   8  * Whenever a struct notes_tree pointer is required below, you may pass NULL in
   9  * order to use the default/internal notes tree. E.g. you only need to pass a
  10  * non-NULL value if you need to refer to several different notes trees
  11  * simultaneously.
  12  */
  13 extern struct notes_tree {
  14         struct int_node *root;
  15         char *ref;
  16         int initialized;
  17 } default_notes_tree;
  18
  19 /*
  20  * Flags controlling behaviour of notes tree initialization
  21  *
  22  * Default behaviour is to initialize the notes tree from the tree object
  23  * specified by the given (or default) notes ref.
  24  */
  25 #define NOTES_INIT_EMPTY 1
  26
  27 /*
  28  * Initialize the given notes_tree with the notes tree structure at the given
  29  * ref. If given ref is NULL, the value of the $GIT_NOTES_REF environment
  30  * variable is used, and if that is missing, the default notes ref is used
  31  * ("refs/notes/commits").
  32  *
  33  * If you need to re-intialize a notes_tree structure (e.g. when switching from
  34  * one notes ref to another), you must first de-initialize the notes_tree
  35  * structure by calling free_notes(struct notes_tree *).
  36  *
  37  * If you pass t == NULL, the default internal notes_tree will be initialized.
  38  *
  39  * Precondition: The notes_tree structure is zeroed (this can be achieved with
  40  * memset(t, 0, sizeof(struct notes_tree)))
  41  */
  42 void init_notes(struct notes_tree *t, const char *notes_ref, int flags);
  43
  44 /*
  45  * Add the given note object to the given notes_tree structure
  46  *
  47  * IMPORTANT: The changes made by add_note() to the given notes_tree structure
  48  * are not persistent until a subsequent call to write_notes_tree() returns
  49  * zero.
  50  */
  51 void add_note(struct notes_tree *t, const unsigned char *object_sha1,
  52                 const unsigned char *note_sha1);
  53
  54 /*
  55  * Remove the given note object from the given notes_tree structure
  56  *
  57  * IMPORTANT: The changes made by remove_note() to the given notes_tree
  58  * structure are not persistent until a subsequent call to write_notes_tree()
  59  * returns zero.
  60  */
  61 void remove_note(struct notes_tree *t, const unsigned char *object_sha1);
  62
  63 /*
  64  * Get the note object SHA1 containing the note data for the given object
  65  *
  66  * Return NULL if the given object has no notes.
  67  */
  68 const unsigned char *get_note(struct notes_tree *t,
  69                 const unsigned char *object_sha1);
  70
  71 /*
  72  * Flags controlling behaviour of for_each_note()
  73  *
  74  * Default behaviour of for_each_note() is to traverse every single note object
  75  * in the given notes tree, unpacking subtree entries along the way.
  76  * The following flags can be used to alter the default behaviour:
  77  *
  78  * - DONT_UNPACK_SUBTREES causes for_each_note() NOT to unpack and recurse into
  79  *   subtree entries while traversing the notes tree. This causes notes within
  80  *   those subtrees NOT to be passed to the callback. Use this flag if you
  81  *   don't want to traverse _all_ notes, but only want to traverse the parts
  82  *   of the notes tree that have already been unpacked (this includes at least
  83  *   all notes that have been added/changed).
  84  *
  85  * - YIELD_SUBTREES causes any subtree entries that are encountered to be
  86  *   passed to the callback, before recursing into them. Subtree entries are
  87  *   not note objects, but represent intermediate directories in the notes
  88  *   tree. When passed to the callback, subtree entries will have a trailing
  89  *   slash in their path, which the callback may use to differentiate between
  90  *   note entries and subtree entries. Note that already-unpacked subtree
  91  *   entries are not part of the notes tree, and will therefore not be yielded.
  92  *   If this flag is used together with DONT_UNPACK_SUBTREES, for_each_note()
  93  *   will yield the subtree entry, but not recurse into it.
  94  */
  95 #define FOR_EACH_NOTE_DONT_UNPACK_SUBTREES 1
  96 #define FOR_EACH_NOTE_YIELD_SUBTREES 2
  97
  98 /*
  99  * Invoke the specified callback function for each note in the given notes_tree
 100  *
 101  * If the callback returns nonzero, the note walk is aborted, and the return
 102  * value from the callback is returned from for_each_note(). Hence, a zero
 103  * return value from for_each_note() indicates that all notes were walked
 104  * successfully.
 105  *
 106  * IMPORTANT: The callback function is NOT allowed to change the notes tree.
 107  * In other words, the following functions can NOT be invoked (on the current
 108  * notes tree) from within the callback:
 109  * - add_note()
 110  * - remove_note()
 111  * - free_notes()
 112  */
 113 typedef int each_note_fn(const unsigned char *object_sha1,
 114                 const unsigned char *note_sha1, char *note_path,
 115                 void *cb_data);
 116 int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
 117                 void *cb_data);
 118
 119 /*
 120  * Write the given notes_tree structure to the object database
 121  *
 122  * Creates a new tree object encapsulating the current state of the given
 123  * notes_tree, and stores its SHA1 into the 'result' argument.
 124  *
 125  * Returns zero on success, non-zero on failure.
 126  *
 127  * IMPORTANT: Changes made to the given notes_tree are not persistent until
 128  * this function has returned zero. Please also remember to create a
 129  * corresponding commit object, and update the appropriate notes ref.
 130  */
 131 int write_notes_tree(struct notes_tree *t, unsigned char *result);
 132
 133 /*
 134  * Free (and de-initialize) the given notes_tree structure
 135  *
 136  * IMPORTANT: Changes made to the given notes_tree since the last, successful
 137  * call to write_notes_tree() will be lost.
 138  */
 139 void free_notes(struct notes_tree *t);
 140
 141 /* Flags controlling how notes are formatted */
 142 #define NOTES_SHOW_HEADER 1
 143 #define NOTES_INDENT 2
 144
 145 /*
 146  * Fill the given strbuf with the notes associated with the given object.
 147  *
 148  * If the given notes_tree structure is not initialized, it will be auto-
 149  * initialized to the default value (see documentation for init_notes() above).
 150  * If the given notes_tree is NULL, the internal/default notes_tree will be
 151  * used instead.
 152  *
 153  * 'flags' is a bitwise combination of the above formatting flags.
 154  */
 155 void format_note(struct notes_tree *t, const unsigned char *object_sha1,
 156                 struct strbuf *sb, const char *output_encoding, int flags);
 157
 158 #endif