diff options
Diffstat (limited to 'editor.c')
| -rw-r--r-- | editor.c | 28 |
1 files changed, 26 insertions, 2 deletions
@@ -109,6 +109,7 @@ static void action_free(Action *a); static void action_push(Action **stack, Action *action); static Action *action_pop(Action **stack); +/* allocate a new buffer of MAX(size, BUFFER_SIZE) bytes */ static Buffer *buffer_alloc(Editor *ed, size_t size) { Buffer *buf = calloc(1, sizeof(Buffer)); if (!buf) @@ -225,6 +226,7 @@ static bool cache_delete(Editor *ed, Piece *p, size_t off, size_t len) { return true; } +/* initialize a span and calculate its length */ static void span_init(Span *span, Piece *start, Piece *end) { size_t len = 0; span->start = start; @@ -237,6 +239,13 @@ static void span_init(Span *span, Piece *start, Piece *end) { span->len = len; } +/* swap out an old span and replace it with a new one. + * + * - if old is an empty span do not remove anything, just insert the new one + * - if new is an empty span do not insert anything, just remove the old one + * + * adjusts the document size accordingly. + */ static void span_swap(Editor *ed, Span *old, Span *new) { /* TODO use a balanced search tree to keep the pieces instead of a doubly linked list. @@ -272,12 +281,14 @@ static Action *action_pop(Action **stack) { return action; } +/* allocate a new action, empty the redo stack and push the new action onto + * the undo stack. all further changes will be associated with this action. */ static Action *action_alloc(Editor *ed) { Action *old, *new = calloc(1, sizeof(Action)); if (!new) return NULL; new->time = time(NULL); - /* throw a away all old redo operations, since we are about to perform a new one */ + /* throw a away all old redo operations */ while ((old = action_pop(&ed->redo))) action_free(old); ed->current_action = new; @@ -362,6 +373,8 @@ static Location piece_get_public(Editor *ed, size_t pos) { return loc; } +/* allocate a new change, associate it with current action or a newly + * allocated one if none exists. */ static Change *change_alloc(Editor *ed) { Action *a = ed->current_action; if (!a) { @@ -451,7 +464,8 @@ bool editor_insert(Editor *ed, size_t pos, char *text) { Piece *new = NULL; if (off == p->len) { - /* insert between two existing pieces */ + /* insert between two existing pieces, hence there is nothing to + * remove, just add a new piece holding the extra text */ if (!(new = piece_alloc(ed))) return false; piece_init(new, p, p->next, text, len); @@ -482,6 +496,7 @@ bool editor_insert(Editor *ed, size_t pos, char *text) { return true; } +/* undo all changes of the last action, return whether changes existed */ bool editor_undo(Editor *ed) { Action *a = action_pop(&ed->undo); if (!a) @@ -494,6 +509,7 @@ bool editor_undo(Editor *ed) { return true; } +/* redo all changes of the last action, return whether changes existed */ bool editor_redo(Editor *ed) { Action *a = action_pop(&ed->redo); if (!a) @@ -513,6 +529,10 @@ bool copy_content(void *data, size_t pos, const char *content, size_t len) { return true; } +/* save current content to given filename. the data is first saved to + * a file called `.filename.tmp` and then atomically moved to its final + * (possibly alredy existing) destination using rename(2). + */ int editor_save(Editor *ed, const char *filename) { size_t len = strlen(filename) + 10; char tmpname[len]; @@ -546,6 +566,8 @@ err: return -1; } +/* load the given file as starting point for further editing operations. + * to start with an empty document, pass NULL as filename. */ Editor *editor_load(const char *filename) { Editor *ed = calloc(1, sizeof(Editor)); if (!ed) @@ -705,6 +727,8 @@ bool editor_replace(Editor *ed, size_t pos, char *c) { return true; } +/* preserve the current text content such that it can be restored by + * means of undo/redo operations */ void editor_snapshot(Editor *ed) { ed->current_action = NULL; ed->cache = NULL; |