text: #ifndef QUOTE_H
  #define QUOTE_H
  
  struct strbuf;
  
  /* Help to copy the thing properly quoted for the shell safety.
   * any single quote is replaced with '\'', any exclamation point
   * is replaced with '\!', and the whole thing is enclosed in a
   * single quote pair.
   *
   * For example, if you are passing the result to system() as an
   * argument:
   *
   * sprintf(cmd, "foobar %s %s", sq_quote(arg0), sq_quote(arg1))
   *
   * would be appropriate.  If the system() is going to call ssh to
   * run the command on the other side:
   *
   * sprintf(cmd, "git-diff-tree %s %s", sq_quote(arg0), sq_quote(arg1));
   * sprintf(rcmd, "ssh %s %s", sq_quote(host), sq_quote(cmd));
   *
   * Note that the above examples leak memory!  Remember to free result from
   * sq_quote() in a real application.
   *
   * sq_quote_buf() writes to an existing buffer of specified size; it
   * will return the number of characters that would have been written
   * excluding the final null regardless of the buffer size.
   *
   * sq_quotef() quotes the entire formatted string as a single result.
   */
  
  extern void sq_quote_buf(struct strbuf *, const char *src);
  extern void sq_quote_argv(struct strbuf *, const char **argv, size_t maxlen);
  extern void sq_quotef(struct strbuf *, const char *fmt, ...);
  
  /* This unwraps what sq_quote() produces in place, but returns
   * NULL if the input does not look like what sq_quote would have
   * produced.
   */
  extern char *sq_dequote(char *);
  
  /*
   * Same as the above, but can be used to unwrap many arguments in the
   * same string separated by space. Like sq_quote, it works in place,
   * modifying arg and appending pointers into it to argv.
   */
  extern int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc);
  
  /*
   * Same as above, but store the unquoted strings in an argv_array. We will
   * still modify arg in place, but unlike sq_dequote_to_argv, the argv_array
   * will duplicate and take ownership of the strings.
   */
  struct argv_array;
  extern int sq_dequote_to_argv_array(char *arg, struct argv_array *);
  
  extern int unquote_c_style(struct strbuf *, const char *quoted, const char **endp);
  extern size_t quote_c_style(const char *name, struct strbuf *, FILE *, int no_dq);
  extern void quote_two_c_style(struct strbuf *, const char *, const char *, int);
  
  extern void write_name_quoted(const char *name, FILE *, int terminator);
  extern void write_name_quoted_relative(const char *name, const char *prefix,
  		FILE *fp, int terminator);
  
  /* quote path as relative to the given prefix */
  extern char *quote_path_relative(const char *in, const char *prefix,
  			  struct strbuf *out);
  
  /* quoting as a string literal for other languages */
  extern void perl_quote_buf(struct strbuf *sb, const char *src);
  extern void python_quote_buf(struct strbuf *sb, const char *src);
  extern void tcl_quote_buf(struct strbuf *sb, const char *src);
  extern void basic_regex_quote_buf(struct strbuf *sb, const char *src);
  
  #endif
  