vi: clear undo buffer when we change to another file
authorDenys Vlasenko <vda.linux@googlemail.com>
Thu, 3 Apr 2014 10:47:48 +0000 (12:47 +0200)
committerDenys Vlasenko <vda.linux@googlemail.com>
Thu, 3 Apr 2014 10:47:48 +0000 (12:47 +0200)
function                                             old     new   delta
init_text_buffer                                     156     190     +34
undo_push                                            360     382     +22
count_lines                                           74      72      -2
undo_pop                                             246     222     -24
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/2 up/down: 56/-26)             Total: 30 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
editors/vi.c

index 71086c901680ddcabae97a6c4f7999f48acaa774..a978e0fcb8a0ccba085a203d90ffb7194b60688f 100644 (file)
@@ -306,8 +306,8 @@ struct globals {
        smallint editing;        // >0 while we are editing a file
                                 // [code audit says "can be 0, 1 or 2 only"]
        smallint cmd_mode;       // 0=command  1=insert 2=replace
-       int file_modified;       // buffer contents changed (counter, not flag!)
-       int last_file_modified;  // = -1;
+       int modified_count;      // buffer contents changed if !0
+       int last_modified_count; // = -1;
        int save_argc;           // how many file names on cmd line
        int cmdcnt;              // repetition count
        unsigned rows, columns;  // the terminal screen is this size
@@ -378,37 +378,37 @@ struct globals {
        char scr_out_buf[MAX_SCR_COLS + MAX_TABSTOP * 2];
 #if ENABLE_FEATURE_VI_UNDO
 // undo_push() operations
-#define UNDO_INS 0
-#define UNDO_DEL 1
-#define UNDO_INS_CHAIN 2
-#define UNDO_DEL_CHAIN 3
+#define UNDO_INS         0
+#define UNDO_DEL         1
+#define UNDO_INS_CHAIN   2
+#define UNDO_DEL_CHAIN   3
 // UNDO_*_QUEUED must be equal to UNDO_xxx ORed with UNDO_QUEUED_FLAG
 #define UNDO_QUEUED_FLAG 4
-#define UNDO_INS_QUEUED 4
-#define UNDO_DEL_QUEUED 5
-#define UNDO_USE_SPOS 32
-#define UNDO_EMPTY 64
+#define UNDO_INS_QUEUED  4
+#define UNDO_DEL_QUEUED  5
+#define UNDO_USE_SPOS   32
+#define UNDO_EMPTY      64
 // Pass-through flags for functions that can be undone
-#define NO_UNDO 0
-#define ALLOW_UNDO 1
+#define NO_UNDO          0
+#define ALLOW_UNDO       1
 #define ALLOW_UNDO_CHAIN 2
-#if ENABLE_FEATURE_VI_UNDO_QUEUE
+# if ENABLE_FEATURE_VI_UNDO_QUEUE
 #define ALLOW_UNDO_QUEUED 3
        char undo_queue_state;
        int undo_q;
        char *undo_queue_spos;  // Start position of queued operation
        char undo_queue[CONFIG_FEATURE_VI_UNDO_QUEUE_MAX];
-#else
+# else
 // If undo queuing disabled, don't invoke the missing queue logic
 #define ALLOW_UNDO_QUEUED 1
-#endif /* ENABLE_FEATURE_VI_UNDO_QUEUE */
+# endif
 
        struct undo_object {
                struct undo_object *prev;       // Linking back avoids list traversal (LIFO)
-               int u_type;             // 0=deleted, 1=inserted, 2=swapped
                int start;              // Offset where the data should be restored/deleted
                int length;             // total data size
-               char *undo_text;        // ptr to text that will be inserted
+               uint8_t u_type;         // 0=deleted, 1=inserted, 2=swapped
+               char undo_text[1];      // text that was deleted (if deletion)
        } *undo_stack_tail;
 #endif /* ENABLE_FEATURE_VI_UNDO */
 
@@ -423,8 +423,8 @@ struct globals {
 #define vi_setops               (G.vi_setops          )
 #define editing                 (G.editing            )
 #define cmd_mode                (G.cmd_mode           )
-#define file_modified           (G.file_modified      )
-#define last_file_modified      (G.last_file_modified )
+#define modified_count          (G.modified_count     )
+#define last_modified_count     (G.last_modified_count)
 #define save_argc               (G.save_argc          )
 #define cmdcnt                  (G.cmdcnt             )
 #define rows                    (G.rows               )
@@ -485,7 +485,7 @@ struct globals {
 
 #define INIT_G() do { \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
-       last_file_modified = -1; \
+       last_modified_count = -1; \
        /* "" but has space for 2 chars: */ \
        IF_FEATURE_VI_SEARCH(last_search_pattern = xzalloc(2);) \
 } while (0)
@@ -608,6 +608,7 @@ static char what_reg(void);         // what is letter of current YDreg
 static void check_context(char);       // remember context for '' command
 #endif
 #if ENABLE_FEATURE_VI_UNDO
+static void flush_undo_data(void);
 static void undo_push(char *, unsigned int, unsigned char);    // Push an operation on the undo stack
 static void undo_pop(void);    // Undo the last operation
 # if ENABLE_FEATURE_VI_UNDO_QUEUE
@@ -616,6 +617,7 @@ static void undo_queue_commit(void);        // Flush any queued objects to the undo sta
 # define undo_queue_commit() ((void)0)
 # endif
 #else
+#define flush_undo_data()   ((void)0)
 #define undo_queue_commit() ((void)0)
 #endif
 
@@ -725,6 +727,8 @@ static int init_text_buffer(char *fn)
        int rc;
        int size = file_size(fn);       // file size. -1 means does not exist.
 
+       flush_undo_data();
+
        /* allocate/reallocate text buffer */
        free(text);
        text_size = size + 10240;
@@ -735,14 +739,14 @@ static int init_text_buffer(char *fn)
                current_filename = xstrdup(fn);
        }
        if (size < 0) {
-               // file dont exist. Start empty buf with dummy line
+               // file doesnt exist. Start empty buf with dummy line
                char_insert(text, '\n', NO_UNDO);
                rc = 0;
        } else {
                rc = file_insert(fn, text, 1);
        }
-       file_modified = 0;
-       last_file_modified = -1;
+       modified_count = 0;
+       last_modified_count = -1;
 #if ENABLE_FEATURE_VI_YANKMARK
        /* init the marks. */
        memset(mark, 0, sizeof(mark));
@@ -1124,7 +1128,7 @@ static void colon(char *buf)
                dot_skip_over_ws();
        } else if (strncmp(cmd, "edit", i) == 0) {      // Edit a file
                // don't edit, if the current file has been modified
-               if (file_modified && !useforce) {
+               if (modified_count && !useforce) {
                        status_line_bold("No write since last change (:%s! overrides)", cmd);
                        goto ret;
                }
@@ -1227,7 +1231,7 @@ static void colon(char *buf)
                        goto ret;
                }
                // don't exit if the file been modified
-               if (file_modified) {
+               if (modified_count) {
                        status_line_bold("No write since last change (:%s! overrides)", cmd);
                        goto ret;
                }
@@ -1280,10 +1284,10 @@ static void colon(char *buf)
                        // if the insert is before "dot" then we need to update
                        if (q <= dot)
                                dot += ch;
-                       // file_modified++;
+                       // modified_count++;
                }
        } else if (strncmp(cmd, "rewind", i) == 0) {    // rewind cmd line args
-               if (file_modified && !useforce) {
+               if (modified_count && !useforce) {
                        status_line_bold("No write since last change (:%s! overrides)", cmd);
                } else {
                        // reset the filenames to edit
@@ -1438,8 +1442,8 @@ static void colon(char *buf)
                } else {
                        status_line("'%s' %dL, %dC", fn, li, l);
                        if (q == text && r == end - 1 && l == ch) {
-                               file_modified = 0;
-                               last_file_modified = -1;
+                               modified_count = 0;
+                               last_modified_count = -1;
                        }
                        if ((cmd[0] == 'x' || cmd[1] == 'q' || cmd[1] == 'n'
                            || cmd[0] == 'X' || cmd[1] == 'Q' || cmd[1] == 'N'
@@ -1940,7 +1944,7 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 # endif
                }
 #else
-               file_modified++;
+               modified_count++;
 #endif /* ENABLE_FEATURE_VI_UNDO */
                p++;
        } else if (c == 27) {   // Is this an ESC?
@@ -1988,7 +1992,7 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 # endif
                }
 #else
-               file_modified++;
+               modified_count++;
 #endif /* ENABLE_FEATURE_VI_UNDO */
                p += 1 + stupid_insert(p, c);   // insert the char
 #if ENABLE_FEATURE_VI_SETOPTS
@@ -2206,8 +2210,19 @@ static void showmatching(char *p)
 #endif /* FEATURE_VI_SETOPTS */
 
 #if ENABLE_FEATURE_VI_UNDO
+static void flush_undo_data(void)
+{
+       struct undo_object *undo_entry;
+
+       while (undo_stack_tail) {
+               undo_entry = undo_stack_tail;
+               undo_stack_tail = undo_entry->prev;
+               free(undo_entry);
+       }
+}
+
 // Undo functions and hooks added by Jody Bruchon (jody@jodybruchon.com)
-static void undo_push(char *src, unsigned int length, unsigned char u_type)    // Add to the undo stack
+static void undo_push(char *src, unsigned int length, uint8_t u_type)  // Add to the undo stack
 {
        struct undo_object *undo_entry;
 
@@ -2275,10 +2290,19 @@ static void undo_push(char *src, unsigned int length, unsigned char u_type)     // A
        u_type = u_type & ~UNDO_QUEUED_FLAG;
 #endif
 
-       // Allocate a new undo object and use it as the stack tail
-       undo_entry = xzalloc(sizeof(*undo_entry));
-       undo_entry->prev = undo_stack_tail;
-       undo_stack_tail = undo_entry;
+       // Allocate a new undo object
+       if (u_type == UNDO_DEL || u_type == UNDO_DEL_CHAIN) {
+               // For UNDO_DEL objects, save deleted text
+               if ((src + length) == end)
+                       length--;
+               // If this deletion empties text[], strip the newline. When the buffer becomes
+               // zero-length, a newline is added back, which requires this to compensate.
+               undo_entry = xzalloc(offsetof(struct undo_object, undo_text) + length);
+               memcpy(undo_entry->undo_text, src, length);
+       } else {
+               undo_entry = xzalloc(sizeof(*undo_entry));
+       }
+       undo_entry->length = length;
 #if ENABLE_FEATURE_VI_UNDO_QUEUE
        if ((u_type & UNDO_USE_SPOS) != 0) {
                undo_entry->start = undo_queue_spos - text;     // use start position from queue
@@ -2289,18 +2313,12 @@ static void undo_push(char *src, unsigned int length, unsigned char u_type)     // A
 #else
        undo_entry->start = src - text;
 #endif
-       // For UNDO_DEL objects, copy the deleted text somewhere
        undo_entry->u_type = u_type;
-       if (u_type == UNDO_DEL || u_type == UNDO_DEL_CHAIN) {
-               if ((src + length) == end)
-                       length--;
-               // If this deletion empties text[], strip the newline. When the buffer becomes
-               // zero-length, a newline is added back, which requires this to compensate.
-               undo_entry->undo_text = xmalloc(length);
-               memcpy(undo_entry->undo_text, src, length);
-       }
-       undo_entry->length = length;
-       file_modified++;
+
+       // Push it on undo stack
+       undo_entry->prev = undo_stack_tail;
+       undo_stack_tail = undo_entry;
+       modified_count++;
 }
 
 static void undo_pop(void)     // Undo the last operation
@@ -2326,9 +2344,8 @@ static void undo_pop(void)        // Undo the last operation
                u_start = text + undo_entry->start;
                text_hole_make(u_start, undo_entry->length);
                memcpy(u_start, undo_entry->undo_text, undo_entry->length);
-               free(undo_entry->undo_text);
                status_line("Undo [%d] %s %d chars at position %d",
-                       file_modified, "restored",
+                       modified_count, "restored",
                        undo_entry->length, undo_entry->start
                );
                break;
@@ -2339,7 +2356,7 @@ static void undo_pop(void)        // Undo the last operation
                u_end = u_start - 1 + undo_entry->length;
                text_hole_delete(u_start, u_end, NO_UNDO);
                status_line("Undo [%d] %s %d chars at position %d",
-                       file_modified, "deleted",
+                       modified_count, "deleted",
                        undo_entry->length, undo_entry->start
                );
                break;
@@ -2360,7 +2377,7 @@ static void undo_pop(void)        // Undo the last operation
        // Deallocate the undo object we just processed
        undo_stack_tail = undo_entry->prev;
        free(undo_entry);
-       file_modified--;
+       modified_count--;
        // For chained operations, continue popping all the way down the chain.
        if (repeat) {
                undo_pop();     // Follow the undo chain if one exists
@@ -2452,13 +2469,13 @@ static char *text_hole_delete(char *p, char *q, int undo) // delete "p" through
                        break;
 # endif
        }
-       file_modified--;
+       modified_count--;
 #endif
        if (src < text || src > end)
                goto thd0;
        if (dest < text || dest >= end)
                goto thd0;
-       file_modified++;
+       modified_count++;
        if (src >= end)
                goto thd_atend; // just delete the end of the buffer
        memmove(dest, src, cnt);
@@ -2885,7 +2902,7 @@ static int file_insert(const char *fn, char *p, int update_ro_status)
                status_line_bold("can't read '%s'", fn);
        }
 //     if (cnt >= size)
-//             file_modified++;
+//             modified_count++;
        close(fd);
  fi0:
 #if ENABLE_FEATURE_VI_READONLY
@@ -2922,7 +2939,7 @@ static int file_write(char *fn, char *first, char *last)
        ftruncate(fd, charcnt);
        if (charcnt == cnt) {
                // good write
-               //file_modified = FALSE;
+               //modified_count = FALSE;
        } else {
                charcnt = 0;
        }
@@ -3144,7 +3161,7 @@ static int format_edit_status(void)
 
        int cur, percent, ret, trunc_at;
 
-       // file_modified is now a counter rather than a flag.  this
+       // modified_count is now a counter rather than a flag.  this
        // helps reduce the amount of line counting we need to do.
        // (this will cause a mis-reporting of modified status
        // once every MAXINT editing operations.)
@@ -3154,11 +3171,12 @@ static int format_edit_status(void)
        // we're on, then we shouldn't have to do this count_lines()
        cur = count_lines(text, dot);
 
-       // reduce counting -- the total lines can't have
-       // changed if we haven't done any edits.
-       if (file_modified != last_file_modified) {
+       // count_lines() is expensive.
+       // Call it only if something was changed since last time
+       // we were here:
+       if (modified_count != last_modified_count) {
                tot = cur + count_lines(dot, end - 1) - 1;
-               last_file_modified = file_modified;
+               last_modified_count = modified_count;
        }
 
        //    current line         percent
@@ -3185,7 +3203,7 @@ static int format_edit_status(void)
 #if ENABLE_FEATURE_VI_READONLY
                (readonly_mode ? " [Readonly]" : ""),
 #endif
-               (file_modified ? " [Modified]" : ""),
+               (modified_count ? " [Modified]" : ""),
                cur, tot, percent);
 
        if (ret >= 0 && ret < trunc_at)
@@ -3814,7 +3832,7 @@ static void do_cmd(int c)
                if (strncmp(p, "quit", cnt) == 0
                 || strncmp(p, "q!", cnt) == 0   // delete lines
                ) {
-                       if (file_modified && p[1] != '!') {
+                       if (modified_count && p[1] != '!') {
                                status_line_bold("No write since last change (:%s! overrides)", p);
                        } else {
                                editing = 0;
@@ -3829,8 +3847,8 @@ static void do_cmd(int c)
                                if (cnt == -1)
                                        status_line_bold("Write error: %s", strerror(errno));
                        } else {
-                               file_modified = 0;
-                               last_file_modified = -1;
+                               modified_count = 0;
+                               last_modified_count = -1;
                                status_line("'%s' %dL, %dC", current_filename, count_lines(text, end - 1), cnt);
                                if (p[0] == 'x' || p[1] == 'q' || p[1] == 'n'
                                 || p[0] == 'X' || p[1] == 'Q' || p[1] == 'N'
@@ -3963,7 +3981,7 @@ static void do_cmd(int c)
                                undo_push((dot - 1), 1, UNDO_INS_CHAIN);
 #else
                                *dot++ = ' ';
-                               file_modified++;
+                               modified_count++;
 #endif
                                while (isblank(*dot)) { // delete leading WS
                                        text_hole_delete(dot, dot, ALLOW_UNDO_CHAIN);
@@ -4035,7 +4053,7 @@ static void do_cmd(int c)
                        indicate_error(c);
                        break;
                }
-               if (file_modified) {
+               if (modified_count) {
                        if (ENABLE_FEATURE_VI_READONLY && readonly_mode) {
                                status_line_bold("'%s' is read only", current_filename);
                                break;
@@ -4172,7 +4190,7 @@ static void do_cmd(int c)
                        undo_push(dot, 1, UNDO_INS_CHAIN);
 #else
                        *dot = c1;
-                       file_modified++;
+                       modified_count++;
 #endif
                }
                end_cmd_q();    // stop adding to q
@@ -4226,10 +4244,10 @@ static void do_cmd(int c)
 #else
                        if (islower(*dot)) {
                                *dot = toupper(*dot);
-                               file_modified++;
+                               modified_count++;
                        } else if (isupper(*dot)) {
                                *dot = tolower(*dot);
-                               file_modified++;
+                               modified_count++;
                        }
 #endif
                        dot_right();