Change quoting in Process implementation on Windows.

runtime/bin/process_win.cc

Index: runtime/bin/process_win.cc
diff --git a/runtime/bin/process_win.cc b/runtime/bin/process_win.cc
index 31c140cc20db5b9aa32b0fa5bbaf7a06bfe946c8..3cdd7893be08634bc8e49729dd89493960b978ad 100644
--- a/runtime/bin/process_win.cc
+++ b/runtime/bin/process_win.cc
@@ -575,12 +575,18 @@ int Process::Start(const char* path,
   char* command_line = new char[command_line_length];
   int len = 0;
   int remaining = command_line_length;
-  int written = snprintf(command_line + len, remaining, "\"%s\"", path);
+  // Quote the path if it contains a space.
+  char* format = strchr(path, ' ') != NULL ? "\"%s\"" : "%s";

[Anton Muhin, 2012/03/15 11:52:48]

what if argument is already quoted, do we want to care?

[Mads Ager (google), 2012/03/15 14:32:22]

We don't care that the argument is already quoted. However, if we surround the
argument with quotes, we need to escape any quotes in the string:

a " b -> "a \" b"

That will allow the Windows C library arguments parsing to give 'a " b' as one
argument. Similar care should be taken with \ in an argument that we quote.

+  int written = snprintf(command_line + len, remaining, format, path);
   len += written;
   remaining -= written;
   ASSERT(remaining >= 0);
   for (int i = 0; i < arguments_length; i++) {
-    written = snprintf(command_line + len, remaining, " \"%s\"", arguments[i]);
+    // Quote the argument if it contains a space or a tab.
+    bool contains_tab_or_space = ((strchr(arguments[i], ' ') != NULL) ||
+                                  (strchr(arguments[i], '\t') != NULL));

[Anton Muhin, 2012/03/15 11:52:48]

what about other whitespaces?

[Mads Ager (google), 2012/03/15 14:32:22]

In the command-line that you create the arguments are space or tab separated
only.

+    format = contains_tab_or_space ? " \"%s\"" : " %s";
+    written = snprintf(command_line + len, remaining, format, arguments[i]);
     len += written;
     remaining -= written;
     ASSERT(remaining >= 0);