gdb: Allow quoting around string options in the gdb::option framework

Currently string options must be a single string with no whitespace,
this limitation prevents the gdb::option framework being used in some
places.

After this commit, string options can be quoted in single or double
quotes, and quote characters can be escaped with a backslash if needed
to either place them within quotes, or to avoid starting a quoted
argument.

This test adds a new function extract_string_maybe_quoted which is
basically a copy of extract_arg_maybe_quoted from cli/cli-utils.c,
however, the cli-utils.c function will be deleted in the next commit.

There are tests to exercise the new quoting mechanism.

gdb/ChangeLog:

	* cli/cli-option.c (parse_option): Use extract_string_maybe_quoted
	to extract string arguments.
	* common/common-utils.c (extract_string_maybe_quoted): New function.
	* common/common-utils.h (extract_string_maybe_quoted): Declare.

gdb/testsuite/ChangeLog:

	* gdb.base/options.exp (expect_string): Dequote strings in
	results.
	(test-string): Test strings with different quoting and reindent.

6 files changed, 123 insertions, 20 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 90da3d4..5f9872b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2019-07-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* cli/cli-option.c (parse_option): Use extract_string_maybe_quoted
+	to extract string arguments.
+	* common/common-utils.c (extract_string_maybe_quoted): New function.
+	* common/common-utils.h (extract_string_maybe_quoted): Declare.
+
 2019-07-11  Tom Tromey  <tromey@adacore.com>
 
 	* main.c (get_init_files): Use GDBINIT, not gdbinit.
diff --git a/gdb/cli/cli-option.c b/gdb/cli/cli-option.c
index 07d552b..eb8ef79 100644
--- a/gdb/cli/cli-option.c
+++ b/gdb/cli/cli-option.c
@@ -434,13 +434,12 @@ parse_option (gdb::array_view<const option_def_group> options_group,
 	  }
 
 	const char *arg_start = *args;
-	*args = skip_to_space (*args);
-
+	std::string str = extract_string_maybe_quoted (args);
 	if (*args == arg_start)
 	  error (_("-%s requires an argument"), match->name);
 
 	option_value val;
-	val.string = savestring (arg_start, *args - arg_start);
+	val.string = xstrdup (str.c_str ());
 	return option_def_and_value {*match, match_ctx, val};
       }
 
diff --git a/gdb/gdbsupport/common-utils.c b/gdb/gdbsupport/common-utils.c
index 384029d..d1059de 100644
--- a/gdb/gdbsupport/common-utils.c
+++ b/gdb/gdbsupport/common-utils.c
@@ -160,6 +160,65 @@ savestring (const char *ptr, size_t len)
   return p;
 }
 
+/* See documentation in common-utils.h.  */
+
+std::string
+extract_string_maybe_quoted (const char **arg)
+{
+  bool squote = false;
+  bool dquote = false;
+  bool bsquote = false;
+  std::string result;
+  const char *p = *arg;
+
+  /* Find the start of the argument.  */
+  p = skip_spaces (p);
+
+  /* Parse p similarly to gdb_argv buildargv function.  */
+  while (*p != '\0')
+    {
+      if (isspace (*p) && !squote && !dquote && !bsquote)
+	break;
+      else
+	{
+	  if (bsquote)
+	    {
+	      bsquote = false;
+	      result += *p;
+	    }
+	  else if (*p == '\\')
+	    bsquote = true;
+	  else if (squote)
+	    {
+	      if (*p == '\'')
+		squote = false;
+	      else
+		result += *p;
+	    }
+	  else if (dquote)
+	    {
+	      if (*p == '"')
+		dquote = false;
+	      else
+		result += *p;
+	    }
+	  else
+	    {
+	      if (*p == '\'')
+		squote = true;
+	      else if (*p == '"')
+		dquote = true;
+	      else
+		result += *p;
+	    }
+	  p++;
+	}
+    }
+
+  *arg = p;
+  return result;
+}
+
 /* The bit offset of the highest byte in a ULONGEST, for overflow
    checking.  */
 
diff --git a/gdb/gdbsupport/common-utils.h b/gdb/gdbsupport/common-utils.h
index 52bf343..a5312cb 100644
--- a/gdb/gdbsupport/common-utils.h
+++ b/gdb/gdbsupport/common-utils.h
@@ -94,6 +94,16 @@ void string_vappendf (std::string &dest, const char* fmt, va_list args)
 
 char *savestring (const char *ptr, size_t len);
 
+/* Extract the next word from ARG.  The next word is defined as either,
+   everything up to the next space, or, if the next word starts with either
+   a single or double quote, then everything up to the closing quote.  The
+   enclosing quotes are not returned in the result string.  The pointer in
+   ARG is updated to point to the first character after the end of the
+   word, or, for quoted words, the first character after the closing
+   quote.  */
+
+std::string extract_string_maybe_quoted (const char **arg);
+
 /* The strerror() function can return NULL for errno values that are
    out of range.  Provide a "safe" version that always returns a
    printable string.  */
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 247171a..238fcfc 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-11  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.base/options.exp (expect_string): Dequote strings in
+	results.
+	(test-string): Test strings with different quoting and reindent.
+
 2019-07-10  Tom Tromey  <tromey@adacore.com>
 
 	* gdb.ada/mi_ex_cond.exp: Update expected results.
diff --git a/gdb/testsuite/gdb.base/options.exp b/gdb/testsuite/gdb.base/options.exp
index e8f571d..561ca1d 100644
--- a/gdb/testsuite/gdb.base/options.exp
+++ b/gdb/testsuite/gdb.base/options.exp
@@ -128,6 +128,13 @@ proc expect_integer {option val operand} {
 # test-options xxx", with -string set to $STR.  OPERAND is the
 # expected operand.
 proc expect_string {str operand} {
+    # Dequote the string in the expected output.
+    if { ( [string range $str 0 0] == "\""
+	   && [string range $str end end] == "\"")
+	 || ([string range $str 0 0] == "'"
+	     && [string range $str end end] == "'")} {
+	set str [string range $str 1 end-1]
+    }
     return "-flag 0 -xx1 0 -xx2 0 -bool 0 -enum xxx -uint 0 -zuint-unl 0 -string '$str' -- $operand"
 }
 
@@ -967,26 +974,41 @@ proc_with_prefix test-string {variant} {
 	    "-string requires an argument"
     }
 
-    res_test_gdb_complete_none \
-	"1 [expect_none ""]" \
-	"$cmd -string STR"
-    gdb_test "$cmd -string STR --" [expect_string "STR" ""]
+    foreach_with_prefix str {
+	"STR"
+	"\"STR\""
+	"\\\"STR"
+	"'STR'"
+	"\\'STR"
+	"\"STR AAA\""
+	"'STR BBB'"
+	"\"STR 'CCC' DDD\""
+	"'STR \"EEE\" FFF'"
+	"\"STR \\\"GGG\\\" HHH\""
+	"'STR \\\'III\\\' JJJ'"
+    } {
+	res_test_gdb_complete_none \
+	    "1 [expect_none ""]" \
+	    "$cmd -string ${str}"
+	gdb_test "$cmd -string ${str} --" [expect_string "${str}" ""]
 
-    # Completing at "-" after parsing STR should list all options.
-    res_test_gdb_complete_multiple \
-	"1 [expect_string "STR" "-"]" \
-	"$cmd -string STR " "-" "" $all_options
+	# Completing at "-" after parsing STR should list all options.
+	res_test_gdb_complete_multiple \
+	    "1 [expect_string "${str}" "-"]" \
+	    "$cmd -string ${str} " "-" "" $all_options
 
-    # Check that only FOO is considered part of the string's value.
-    # I.e., that we stop parsing the string at the first whitespace.
-    if {$variant == "require-delimiter"} {
-	res_test_gdb_complete_none \
-	    "1 [expect_string "FOO" "BAR"]" \
-	    "$cmd -string FOO BAR"
-    } else {
-	res_test_gdb_complete_none "0 BAR" "$cmd -string FOO BAR"
+	# Check that only $STR is considered part of the string's value.
+	# I.e., that we stop parsing the string at the first
+	# whitespace or after the closing quote of $STR.
+	if {$variant == "require-delimiter"} {
+	    res_test_gdb_complete_none \
+		"1 [expect_string "${str}" "BAR"]" \
+		"$cmd -string ${str} BAR"
+	} else {
+	    res_test_gdb_complete_none "0 BAR" "$cmd -string ${str} BAR"
+	}
+	gdb_test "$cmd -string ${str} BAR --" "Unrecognized option at: BAR --"
     }
-    gdb_test "$cmd -string FOO BAR --" "Unrecognized option at: BAR --"
 }
 
 # Run the options framework tests first.