Fix for:

  bug #26215: mysql command line client should not strip comments
              from SQL statements
and
  bug #11230: Keeping comments when storing stored procedures

With the introduction of multiline comments support in the command line
client (mysql) in MySQL 4.1, it became impossible to preserve
client-side comments within single SQL statements or stored routines.
This feature was useful for monitoring tools and maintenance.

The patch adds a new option to the command line client
('--enable-comments', '-c') which allows to preserve SQL comments and
send them to the server for single SQL statements, and to keep comments
in the code for stored procedures / functions / triggers.

The patch is a modification of the contributed patch from bug #11230
with the following changes:
- code style changes to conform to the coding guidelines
- changed is_prefix() to my_strnncoll() to detect the DELIMITER
command, since the first one is case-sensitive and not charset-aware
- renamed t/comments-51.* to t/mysql_comments.*
- removed tests for comments in triggers since 5.0 does not have SHOW
CREATE TRIGGER (those tests will be added back in 5.1).

The test cases are only for bug #11230. No automated test case for bug
#26215 is possible due to the test suite deficiencies (though the cases
from the bug report were tested manually).

1 files changed, 125 insertions, 43 deletions

diff --git a/client/mysql.cc b/client/mysql.cc
index 8e1b6c2a9b4..2c6d0df2274 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -140,6 +140,7 @@ static my_bool info_flag=0,ignore_errors=0,wait_flag=0,quick=0,
                default_pager_set= 0, opt_sigint_ignore= 0,
                show_warnings= 0;
 static volatile int executing_query= 0, interrupted_query= 0;
+static my_bool preserve_comments= 0;
 static ulong opt_max_allowed_packet, opt_net_buffer_length;
 static uint verbose=0,opt_silent=0,opt_mysql_port=0, opt_local_infile=0;
 static my_string opt_mysql_unix_port=0;
@@ -754,6 +755,10 @@ static struct my_option my_long_options[] =
   {"show-warnings", OPT_SHOW_WARNINGS, "Show warnings after every statement.",
     (gptr*) &show_warnings, (gptr*) &show_warnings, 0, GET_BOOL, NO_ARG, 
     0, 0, 0, 0, 0, 0},
+  {"comments", 'c', "Preserve comments. Send comments to the server."
+   " Comments are discarded by default, enable with --enable-comments",
+   (gptr*) &preserve_comments, (gptr*) &preserve_comments,
+   0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
   { 0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
 };
 
@@ -1131,10 +1136,6 @@ static int read_and_execute(bool interactive)
       status.exit_status=0;
       break;
     }
-    if (!in_string && (line[0] == '#' ||
-		       (line[0] == '-' && line[1] == '-') ||
-		       line[0] == 0))
-      continue;					// Skip comment lines
 
     /*
       Check if line is a mysql command line
@@ -1260,15 +1261,21 @@ static bool add_line(String &buffer,char *line,char *in_string,
 
   for (pos=out=line ; (inchar= (uchar) *pos) ; pos++)
   {
-    if (my_isspace(charset_info,inchar) && out == line && 
-        buffer.is_empty())
-      continue;
+    if (!preserve_comments)
+    {
+      // Skip spaces at the beggining of a statement
+      if (my_isspace(charset_info,inchar) && (out == line) &&
+          buffer.is_empty())
+        continue;
+    }
+        
 #ifdef USE_MB
+    // Accept multi-byte characters as-is
     int length;
     if (use_mb(charset_info) &&
         (length= my_ismbchar(charset_info, pos, end_of_line)))
     {
-      if (!*ml_comment)
+      if (!*ml_comment || preserve_comments)
       {
         while (length--)
           *out++ = *pos++;
@@ -1294,8 +1301,13 @@ static bool add_line(String &buffer,char *line,char *in_string,
       }
       if ((com=find_command(NullS,(char) inchar)))
       {
-        const String tmp(line,(uint) (out-line), charset_info);
-        buffer.append(tmp);
+        // Flush previously accepted characters
+        if (out != line)
+        {
+          buffer.append(line, (uint) (out-line));
+          out= line;
+        }
+        
         if ((*com->func)(&buffer,pos-1) > 0)
           DBUG_RETURN(1);                       // Quit
         if (com->takes_params)
@@ -1323,7 +1335,6 @@ static bool add_line(String &buffer,char *line,char *in_string,
               pos+= delimiter_length - 1; // Point at last delim char
           }
         }
-        out=line;
       }
       else
       {
@@ -1336,46 +1347,106 @@ static bool add_line(String &buffer,char *line,char *in_string,
       }
     }
     else if (!*ml_comment && !*in_string &&
-             (*pos == *delimiter && is_prefix(pos + 1, delimiter + 1) ||
-              buffer.length() == 0 && (out - line) >= 9 &&
-              !my_strcasecmp(charset_info, line, "delimiter")))
-    {					
-      uint old_delimiter_length= delimiter_length;
+             (out - line) >= 9 &&
+             !my_strnncoll(charset_info, (uchar*) pos, 9,
+                           (const uchar*) "delimiter", 9) &&
+             my_isspace(charset_info, pos[9]))
+    {
+      // Flush previously accepted characters
       if (out != line)
-	buffer.append(line, (uint) (out - line));	// Add this line
+      {
+        buffer.append(line, (uint32) (out - line));
+        out= line;
+      }
+
+      // Flush possible comments in the buffer
+      if (!buffer.is_empty())
+      {
+        if (com_go(&buffer, 0) > 0) // < 0 is not fatal
+          DBUG_RETURN(1);
+        buffer.length(0);
+      }
+
+      /*
+        Delimiter wants the get rest of the given line as argument to
+        allow one to change ';' to ';;' and back
+      */
+      buffer.append(pos);
+      if (com_delimiter(&buffer, pos) > 0)
+        DBUG_RETURN(1);
+
+      buffer.length(0);
+      break;
+    }
+    else if (!*ml_comment && !*in_string && is_prefix(pos, delimiter))
+    {
+      // Found a statement. Continue parsing after the delimiter
+      pos+= delimiter_length;
+
+      if (preserve_comments)
+      {
+        while (my_isspace(charset_info, *pos))
+          *out++= *pos++;
+      }
+      // Flush previously accepted characters
+      if (out != line)
+      {
+        buffer.append(line, (uint32) (out-line));
+        out= line;
+      }
+
+      if (preserve_comments && ((*pos == '#') ||
+                                ((*pos == '-') &&
+                                 (pos[1] == '-') &&
+                                 my_isspace(charset_info, pos[2]))))
+      {
+        // Add trailing single line comments to this statement
+        buffer.append(pos);
+        pos+= strlen(pos);
+      }
+
+      pos--;
+
       if ((com= find_command(buffer.c_ptr(), 0)))
       {
-        if (com->func == com_delimiter)
-        {
-          /*
-            Delimiter wants the get rest of the given line as argument to
-            allow one to change ';' to ';;' and back
-          */
-          char *end= strend(pos);
-          buffer.append(pos, (uint) (end - pos));
-          /* Ensure pos will point at \0 after the pos+= below */
-          pos= end - old_delimiter_length + 1;
-        }
-	if ((*com->func)(&buffer, buffer.c_ptr()) > 0)
-	  DBUG_RETURN(1);                       // Quit
+          
+        if ((*com->func)(&buffer, buffer.c_ptr()) > 0)
+          DBUG_RETURN(1);                       // Quit 
       }
       else
       {
-	if (com_go(&buffer, 0) > 0)             // < 0 is not fatal
-	  DBUG_RETURN(1);
+        if (com_go(&buffer, 0) > 0)             // < 0 is not fatal
+          DBUG_RETURN(1);
       }
       buffer.length(0);
-      out= line;
-      pos+= old_delimiter_length - 1;
     }
     else if (!*ml_comment && (!*in_string && (inchar == '#' ||
 			      inchar == '-' && pos[1] == '-' &&
 			      my_isspace(charset_info,pos[2]))))
-      break;					// comment to end of line
+    {
+      // Flush previously accepted characters
+      if (out != line)
+      {
+        buffer.append(line, (uint32) (out - line));
+        out= line;
+      }
+
+      // comment to end of line
+      if (preserve_comments)
+        buffer.append(pos);
+
+      break;
+    }
     else if (!*in_string && inchar == '/' && *(pos+1) == '*' &&
 	     *(pos+2) != '!')
     {
-      pos++;
+      if (preserve_comments)
+      {
+        *out++= *pos++;                       // copy '/'
+        *out++= *pos;                         // copy '*'
+      }
+      else
+        pos++;
       *ml_comment= 1;
       if (out != line)
       {
@@ -1385,8 +1456,21 @@ static bool add_line(String &buffer,char *line,char *in_string,
     }
     else if (*ml_comment && !ss_comment && inchar == '*' && *(pos + 1) == '/')
     {
-      pos++;
+      if (preserve_comments)
+      {
+        *out++= *pos++;                       // copy '*'
+        *out++= *pos;                         // copy '/'
+      }
+      else
+        pos++;
       *ml_comment= 0;
+      if (out != line)
+      {
+        buffer.append(line, (uint32) (out - line));
+        out= line;
+      }
+      // Consumed a 2 chars or more, and will add 1 at most,
+      // so using the 'line' buffer to edit data in place is ok.
       need_space= 1;
     }      
     else
@@ -1401,14 +1485,12 @@ static bool add_line(String &buffer,char *line,char *in_string,
       else if (!*ml_comment && !*in_string &&
 	       (inchar == '\'' || inchar == '"' || inchar == '`'))
 	*in_string= (char) inchar;
-      if (!*ml_comment)
+      if (!*ml_comment || preserve_comments)
       {
         if (need_space && !my_isspace(charset_info, (char)inchar))
-        {
           *out++= ' ';
-          need_space= 0;
-        }
-	*out++= (char) inchar;
+        need_space= 0;
+        *out++= (char) inchar;
       }
     }
   }
@@ -1418,7 +1500,7 @@ static bool add_line(String &buffer,char *line,char *in_string,
     uint length=(uint) (out-line);
     if (buffer.length() + length >= buffer.alloced_length())
       buffer.realloc(buffer.length()+length+IO_SIZE);
-    if (!(*ml_comment) && buffer.append(line,length))
+    if ((!*ml_comment || preserve_comments) && buffer.append(line, length))
       DBUG_RETURN(1);
   }
   DBUG_RETURN(0);