post-review fixes

include/my_sys.h:
  added prototype for the defaults correction function
libmysql/Makefile.shared:
  my_chsize added to libmysql to let my_correct_defaults_file be used from libmysql
mysys/default.c:
  New defaults function added we use it to correct defaults file. Currently the function doesn't lock defaults
  file. This is because of the linking and backwards-compatibility issues. This needs to be fixed later.
mysys/my_chsize.c:
  comment added
server-tools/instance-manager/buffer.cc:
  cleanup
server-tools/instance-manager/commands.cc:
  refactoring: removed do_command method from most of the classes
server-tools/instance-manager/commands.h:
  cleanup
server-tools/instance-manager/guardian.cc:
  cleanup
server-tools/instance-manager/instance.cc:
  cleanup
server-tools/instance-manager/instance_map.cc:
  cleanup
server-tools/instance-manager/instance_options.cc:
  cleanup
server-tools/instance-manager/instance_options.h:
  cleanup
server-tools/instance-manager/listener.cc:
  cleanup
server-tools/instance-manager/log.cc:
  cleanup
server-tools/instance-manager/manager.cc:
  cleanup
server-tools/instance-manager/messages.cc:
  new errors added
server-tools/instance-manager/mysql_connection.cc:
  cleanup
server-tools/instance-manager/mysql_manager_error.h:
  new error codes added
server-tools/instance-manager/mysqlmanager.cc:
  clenup
server-tools/instance-manager/options.cc:
  cleanup
server-tools/instance-manager/parse.cc:
  removed unused function
server-tools/instance-manager/parse.h:
  removed prototype
server-tools/instance-manager/protocol.cc:
  cleanup
server-tools/instance-manager/protocol.h:
  added enum to be used in protocol.cc instead of the constants

mysys/default.c

@@ -50,8 +50,10 @@ const char *default_directories[MAX_DEFAULT_DIRS + 1];
 
 #ifdef __WIN__
 static const char *f_extensions[]= { ".ini", ".cnf", 0 };
+#define NEWLINE "\r\n"
 #else
 static const char *f_extensions[]= { ".cnf", 0 };
+#define NEWLINE "\n"
 #endif
 
 /*
@@ -78,6 +80,142 @@ static void init_default_directories();
 
 static char *remove_end_comment(char *ptr);
 
+/*
+  Add/remove option to the option file section.
+
+  SYNOPSYS
+    my_correct_file()
+    file_location     The location of configuration file to edit
+    option            option to look for
+    option value      The value of the option we would like to set
+    section_name      the name of the section
+    remove_option     This is true if we want to remove the option.
+                      False otherwise.
+  IMPLEMENTATION
+    We open the option file first, then read the file line-by-line,
+    looking for the section we need. At the same time we put these lines
+    into a buffer. Then we look for the option within this section and
+    change/remove it. In the end we get a buffer with modified version of the
+    file. Then we write it to the file, truncate it if needed and close it.
+
+  RETURN
+    0 - ok
+    1 - some error has occured. Probably due to the lack of resourses
+   -1 - cannot open the file
+*/
+
+int my_correct_defaults_file(const char *file_location, const char *option,
+                             const char *option_value,
+                             const char *section_name, int remove_option)
+{
+  FILE *cnf_file;
+  struct stat file_stat;
+  char linebuff[512], *ptr;
+  uint optlen;
+  uint len;
+  char *file_buffer;
+  uint position= 0;
+  int is_found= FALSE;
+
+  optlen= strlen(option);
+
+  DBUG_ENTER("my_correct_file");
+
+  if (!(cnf_file= my_fopen(file_location, O_RDWR, MYF(0))))
+    goto err_fopen;
+
+  /* my_fstat doesn't use the flag parameter */
+  if (my_fstat(fileno(cnf_file), &file_stat, MYF(0)))
+    goto err;
+
+  /*
+    Reserve space to read the contents of the file and some more
+    for the option we want ot add.
+  */
+  file_buffer= (char*) my_malloc(sizeof(char)*
+                       (file_stat.st_size + /* current file size */
+                        optlen +            /* option name len */
+                        2 +                 /* reserve space for newline */
+                        1 +                 /* reserve for '=' char */
+                        strlen(option_value)),  /* option value len */
+                        MYF(MY_WME));
+
+  if (!file_buffer)
+    goto malloc_err;
+  while (fgets(linebuff, sizeof(linebuff), cnf_file))
+  {
+    len= strlen(linebuff);
+
+    /* if the section is found traverse it */
+    if (is_found)
+    {
+      /* skip the old value of the option we are changing */
+      if (strncmp(linebuff, option, optlen))
+      {
+        /* copy all other lines */
+        strmake(file_buffer + position, linebuff, len);
+        position+= len;
+      }
+    }
+    else
+    {
+      strmake(file_buffer + position, linebuff, len);
+      position+= len;
+    }
+
+
+    /* looking for appropriate section */
+    for (ptr= linebuff ; my_isspace(&my_charset_latin1,*ptr) ; ptr++)
+    {}
+
+    if (*ptr == '[')
+    {
+      /* copy the line to the buffer */
+      if (!strncmp(++ptr, section_name, strlen(section_name)))
+      {
+        is_found= TRUE;
+        /* add option */
+        if (!remove_option)
+        {
+          strmake(file_buffer + position, option, optlen);
+          position+= optlen;
+          if (*option_value)
+          {
+            *(file_buffer + position++)= '=';
+            strmake(file_buffer + position, option_value,
+                    strlen(option_value));
+            position+= strlen(option_value);
+          }
+          /* add a newline */
+          strcat(file_buffer + position, NEWLINE);
+          position+= strlen(NEWLINE);
+        }
+      }
+      else
+        is_found= FALSE; /* mark that this section is of no interest to us */
+    }
+
+  }
+
+  if (my_chsize(fileno(cnf_file), position, 0, MYF(MY_WME)) ||
+      my_fseek(cnf_file, 0, MY_SEEK_SET, MYF(0)) ||
+      my_fwrite(cnf_file, file_buffer, position, MYF(MY_NABP)) ||
+      my_fclose(cnf_file, MYF(MY_WME)))
+     goto err;
+
+  my_free(file_buffer, MYF(0));
+
+  DBUG_RETURN(0);
+
+err:
+  my_free(file_buffer, MYF(0));
+malloc_err:
+  my_fclose(cnf_file, MYF(0));
+  DBUG_RETURN(1); /* out of resources */
+err_fopen:
+  DBUG_RETURN(-1); /* cannot access the option file */
+}
+
 
 /*
   Process config files in default directories.

mysys/my_chsize.c

@@ -30,7 +30,9 @@
       MyFlags		Flags
 
   DESCRIPTION
-    my_chsize() truncates file if shorter else fill with the filler character
+    my_chsize() truncates file if shorter else fill with the filler character.
+    The function also changes the file pointer. Usually it points to the end
+    of the file after execution.
 
   RETURN VALUE
     0	Ok