1 files changed, 130 insertions, 5 deletions

diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index df387f9a60..5fe6209a0a 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -144,6 +144,10 @@ void do_debug(char_u *cmd)
 #define CMD_FINISH      4
 #define CMD_QUIT        5
 #define CMD_INTERRUPT   6
+#define CMD_BACKTRACE   7
+#define CMD_FRAME       8
+#define CMD_UP          9
+#define CMD_DOWN        10
 
 
   ++RedrawingDisabled;          /* don't redisplay the window */
@@ -185,6 +189,7 @@ void do_debug(char_u *cmd)
       ignore_script = TRUE;
     }
 
+    xfree(cmdline);
     cmdline = getcmdline_prompt('>', NULL, 0, EXPAND_NOTHING, NULL);
 
     if (typeahead_saved) {
@@ -194,6 +199,7 @@ void do_debug(char_u *cmd)
     ex_normal_busy = save_ex_normal_busy;
 
     cmdline_row = msg_row;
+    msg_starthere();
     if (cmdline != NULL) {
       /* If this is a debug command, set "last_cmd".
        * If not, reset "last_cmd".
@@ -210,8 +216,15 @@ void do_debug(char_u *cmd)
         case 's': last_cmd = CMD_STEP;
           tail = "tep";
           break;
-        case 'f': last_cmd = CMD_FINISH;
-          tail = "inish";
+        case 'f':
+          last_cmd = 0;
+          if (p[1] == 'r') {
+            last_cmd = CMD_FRAME;
+            tail = "rame";
+          } else {
+            last_cmd = CMD_FINISH;
+            tail = "inish";
+          }
           break;
         case 'q': last_cmd = CMD_QUIT;
           tail = "uit";
@@ -219,6 +232,26 @@ void do_debug(char_u *cmd)
         case 'i': last_cmd = CMD_INTERRUPT;
           tail = "nterrupt";
           break;
+        case 'b':
+          last_cmd = CMD_BACKTRACE;
+          if (p[1] == 't') {
+            tail = "t";
+          } else {
+            tail = "acktrace";
+          }
+          break;
+        case 'w':
+          last_cmd = CMD_BACKTRACE;
+          tail = "here";
+          break;
+        case 'u':
+          last_cmd = CMD_UP;
+          tail = "p";
+          break;
+        case 'd':
+          last_cmd = CMD_DOWN;
+          tail = "own";
+          break;
         default: last_cmd = 0;
         }
         if (last_cmd != 0) {
@@ -228,8 +261,9 @@ void do_debug(char_u *cmd)
             ++p;
             ++tail;
           }
-          if (ASCII_ISALPHA(*p))
+          if (ASCII_ISALPHA(*p) && last_cmd != CMD_FRAME) {
             last_cmd = 0;
+          }
         }
       }
 
@@ -259,7 +293,28 @@ void do_debug(char_u *cmd)
           /* Do not repeat ">interrupt" cmd, continue stepping. */
           last_cmd = CMD_STEP;
           break;
+        case CMD_BACKTRACE:
+          do_showbacktrace(cmd);
+          continue;
+        case CMD_FRAME:
+          if (*p == NUL) {
+            do_showbacktrace(cmd);
+          } else {
+            p = skipwhite(p);
+            do_setdebugtracelevel(p);
+          }
+          continue;
+        case CMD_UP:
+          debug_backtrace_level++;
+          do_checkbacktracelevel();
+          continue;
+        case CMD_DOWN:
+          debug_backtrace_level--;
+          do_checkbacktracelevel();
+          continue;
         }
+        // Going out reset backtrace_level
+        debug_backtrace_level = 0;
         break;
       }
 
@@ -269,8 +324,6 @@ void do_debug(char_u *cmd)
       (void)do_cmdline(cmdline, getexline, NULL,
           DOCMD_VERBOSE|DOCMD_EXCRESET);
       debug_break_level = n;
-
-      xfree(cmdline);
     }
     lines_left = (int)(Rows - 1);
   }
@@ -294,6 +347,78 @@ void do_debug(char_u *cmd)
   debug_did_msg = TRUE;
 }
 
+static int get_maxbacktrace_level(void)
+{
+  int maxbacktrace = 0;
+
+  if (sourcing_name != NULL) {
+    char *p = (char *)sourcing_name;
+    char *q;
+    while ((q = strstr(p, "..")) != NULL) {
+      p = q + 2;
+      maxbacktrace++;
+    }
+  }
+  return maxbacktrace;
+}
+
+static void do_setdebugtracelevel(char_u *arg)
+{
+  int level = atoi((char *)arg);
+  if (*arg == '+' || level < 0) {
+    debug_backtrace_level += level;
+  } else {
+    debug_backtrace_level = level;
+  }
+
+  do_checkbacktracelevel();
+}
+
+static void do_checkbacktracelevel(void)
+{
+  if (debug_backtrace_level < 0) {
+    debug_backtrace_level = 0;
+    MSG(_("frame is zero"));
+  } else {
+    int max = get_maxbacktrace_level();
+    if (debug_backtrace_level > max) {
+      debug_backtrace_level = max;
+      smsg(_("frame at highest level: %d"), max);
+    }
+  }
+}
+
+static void do_showbacktrace(char_u *cmd)
+{
+  if (sourcing_name != NULL) {
+    int i = 0;
+    int max = get_maxbacktrace_level();
+    char *cur = (char *)sourcing_name;
+    while (!got_int) {
+      char *next = strstr(cur, "..");
+      if (next != NULL) {
+        *next = NUL;
+      }
+      if (i == max - debug_backtrace_level) {
+        smsg("->%d %s", max - i, cur);
+      } else {
+        smsg("  %d %s", max - i, cur);
+      }
+      i++;
+      if (next == NULL) {
+        break;
+      }
+      *next = '.';
+      cur = next + 2;
+    }
+  }
+  if (sourcing_lnum != 0) {
+    smsg(_("line %" PRId64 ": %s"), (int64_t)sourcing_lnum, cmd);
+  } else {
+    smsg(_("cmd: %s"), cmd);
+  }
+}
+
 /*
  * ":debug".
  */