vi: make context marks more like vi

The context marks that are automatically updated and can be used
with the "''" command didn't behave the same as in vi.  Marks
were only being set for certain editing commands when they should
have been set on successful movement commands.

Make BusyBox vi behave more like vi.

function                                             old     new   delta
.rodata                                           105179  105194     +15
do_cmd                                              4723    4668     -55
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 15/-55)            Total: -40 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 18 deletions

diff --git a/editors/vi.c b/editors/vi.c
index b77406967..922d7ea8d 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -377,7 +377,6 @@ struct globals {
         char *reg[28];          // named register a-z, "D", and "U" 0-25,26,27
         char regtype[28];       // buffer type: WHOLE, MULTI or PARTIAL
         char *mark[28];         // user marks points somewhere in text[]-  a-z and previous context ''
-        char *context_start, *context_end;
 #endif
 #if ENABLE_FEATURE_VI_USE_SIGNALS
         sigjmp_buf restart;     // int_handler() jumps to location remembered here
@@ -496,8 +495,6 @@ struct globals {
 //#define Ureg           (G.Ureg          )
 #define regtype        (G.regtype       )
 #define mark           (G.mark          )
-#define context_start  (G.context_start )
-#define context_end    (G.context_end   )
 #define restart        (G.restart       )
 #define term_orig      (G.term_orig     )
 #define cindex         (G.cindex        )
@@ -1415,18 +1412,10 @@ static char what_reg(void)
 
 static void check_context(char cmd)
 {
-        // A context is defined to be "modifying text"
-        // Any modifying command establishes a new context.
-
-        if (dot < context_start || dot > context_end) {
-                if (strchr(modifying_cmds, cmd) != NULL) {
-                        // we are trying to modify text[]- make this the current context
-                        mark[27] = mark[26];    // move cur to prev
-                        mark[26] = dot; // move local to cur
-                        context_start = prev_line(prev_line(dot));
-                        context_end = next_line(next_line(dot));
-                        //loiter= start_loiter= now;
-                }
+        // Certain movement commands update the context.
+        if (strchr(":%{}'GHLMz/?Nn", cmd) != NULL) {
+                mark[27] = mark[26];    // move cur to prev
+                mark[26] = dot; // move local to cur
         }
 }
 
@@ -1441,8 +1430,6 @@ static char *swap_context(char *p) // goto new context for '' command make this
                 tmp = mark[27];
                 mark[27] = p;
                 mark[26] = p = tmp;
-                context_start = prev_line(prev_line(prev_line(p)));
-                context_end = next_line(next_line(next_line(p)));
         }
         return p;
 }
@@ -3287,6 +3274,9 @@ static void do_cmd(int c)
         int dir;
         int cnt, i, j;
         int c1;
+#if ENABLE_FEATURE_VI_YANKMARK
+        char *orig_dot = dot;
+#endif
 #if ENABLE_FEATURE_VI_UNDO
         int allow_undo = ALLOW_UNDO;
         int undo_del = UNDO_DEL;
@@ -3480,6 +3470,9 @@ static void do_cmd(int c)
                         dot = swap_context(dot);        // swap current and previous context
                         dot_begin();    // go to B-o-l
                         dot_skip_over_ws();
+#if ENABLE_FEATURE_VI_YANKMARK
+                        orig_dot = dot; // this doesn't update stored contexts
+#endif
                 } else {
                         indicate_error();
                 }
@@ -4109,7 +4102,8 @@ static void do_cmd(int c)
                 dot = bound_dot(dot);   // make sure "dot" is valid
         }
 #if ENABLE_FEATURE_VI_YANKMARK
-        check_context(c);       // update the current context
+        if (dot != orig_dot)
+                check_context(c);       // update the current context
 #endif
 
         if (!isdigit(c))