3 files changed, 80 insertions, 44 deletions

diff --git a/libbuild2/script/script.cxx b/libbuild2/script/script.cxx
index b53fc23..ee2c9aa 100644
--- a/libbuild2/script/script.cxx
+++ b/libbuild2/script/script.cxx
@@ -237,56 +237,15 @@ namespace build2
       }
     }
 
-    // Quote a string unconditionally, assuming it contains some special
-    // characters.
-    //
-    // If the quote character is present in the string then it is double
-    // quoted rather than single quoted. In this case the following characters
-    // are escaped:
-    //
-    // \"
-    //
-    static void
-    to_stream_quoted (ostream& o, const char* s)
-    {
-      if (strchr (s, '\'') != nullptr)
-      {
-        o << '"';
-
-        for (; *s != '\0'; ++s)
-        {
-          // Escape characters special inside double quotes.
-          //
-          if (strchr ("\\\"", *s) != nullptr)
-            o << '\\';
-
-          o << *s;
-        }
-
-        o << '"';
-      }
-      else
-        o << '\'' << s << '\'';
-    }
-
-    static inline void
-    to_stream_quoted (ostream& o, const string& s)
-    {
-      to_stream_quoted (o, s.c_str ());
-    }
-
     // Quote if empty or contains spaces or any of the command line special
     // characters.
     //
-    static void
+    static inline void
     to_stream_q (ostream& o, const string& s)
     {
       // NOTE: update dump(line) if adding any new special character.
       //
-      if (s.empty () || s.find_first_of (" |&<>=\\\"'") != string::npos)
-        to_stream_quoted (o, s);
-      else
-        o << s;
+      to_stream_quoted (o, s, " |&<>=\\\"'");
     }
 
     void
diff --git a/libbuild2/utility.cxx b/libbuild2/utility.cxx
index 1135851..ae7c9b0 100644
--- a/libbuild2/utility.cxx
+++ b/libbuild2/utility.cxx
@@ -16,7 +16,7 @@
 #endif
 
 #include <cerrno>   // ENOENT
-#include <cstring>  // strlen(), str[n]cmp()
+#include <cstring>  // strlen(), str[n]cmp(), strchr()
 #include <iostream> // cerr
 
 #include <libbuild2/target.hxx>
@@ -1011,4 +1011,48 @@ namespace build2
 
     return r;
   }
+
+  void
+  to_stream_quoted (ostream& o, const char* s)
+  {
+    if (strchr (s, '\'') != nullptr)
+    {
+      o << '"';
+
+      for (; *s != '\0'; ++s)
+      {
+        // Escape characters special inside double quotes.
+        //
+        if (strchr ("\\\"", *s) != nullptr)
+          o << '\\';
+
+        o << *s;
+      }
+
+      o << '"';
+    }
+    else
+      o << '\'' << s << '\'';
+  }
+
+  void
+  to_stream_quoted (ostream& o, const string& s, const char* special, bool e)
+  {
+    if ((e && s.empty ()) || s.find_first_of (special) != string::npos)
+      to_stream_quoted (o, s);
+    else
+      o << s;
+  }
+
+  void
+  to_stream_quoted (ostream& o, const strings& ss, const char* special)
+  {
+    for (auto b (ss.begin ()), i (b), e (ss.end ()); i != e; ++i)
+    {
+      if (i != b)
+        o << ' ';
+
+      to_stream_quoted (o, *i, special);
+    }
+  }
 }
diff --git a/libbuild2/utility.hxx b/libbuild2/utility.hxx
index 151b409..f4fd7bc 100644
--- a/libbuild2/utility.hxx
+++ b/libbuild2/utility.hxx
@@ -1114,6 +1114,39 @@ namespace build2
   //
   optional<uint64_t>
   parse_number (const string&, uint64_t max = UINT64_MAX);
+
+
+  // Write a string to a stream, single or double-quoting it unconditionally.
+  //
+  // If no quote characters are present in the string, then it is single-
+  // quoted. Otherwise, it is double quoted and the `\"` characters (backslach
+  // and double quote) inside the string are escaped.
+  //
+  LIBBUILD2_SYMEXPORT void
+  to_stream_quoted (ostream&, const char*);
+
+  inline void
+  to_stream_quoted (ostream& o, const string& s)
+  {
+    to_stream_quoted (o, s.c_str ());
+  }
+
+  // As above but only quote the string if it contains any of the specified
+  // special characters (which should include backslash as well as single and
+  // double quotes) or is empty (unless empty is false).
+  //
+  LIBBUILD2_SYMEXPORT void
+  to_stream_quoted (ostream&, const string&,
+                    const char* special, bool empty = true);
+
+  // Write a vector of strings to a stream separating elements with a space
+  // and quoting each element if it is empty or contains any of the specified
+  // special characters (which should include space and backslash as well as
+  // single and double quotes; this is also the default which is suitable for
+  // displaying command line options, etc).
+  //
+  LIBBUILD2_SYMEXPORT void
+  to_stream_quoted (ostream&, const strings&, const char* special = " \\\"'");
 }
 
 #include <libbuild2/utility.ixx>