Move extract_canonical_hostname to AIPerHostRequestQueue::extract_canonical_hostname.

This to make it available to the texture fetcher.

indra/llmessage/aicurlperhost.cpp

@@ -64,6 +64,56 @@ void intrusive_ptr_release(RefCountedThreadSafePerHostRequestQueue* per_host)
 
 using namespace AICurlPrivate;
 
+// url must be of the form
+// (see http://www.ietf.org/rfc/rfc3986.txt Appendix A for definitions not given here):
+//
+// url			= sheme ":" hier-part [ "?" query ] [ "#" fragment ]
+// hier-part	= "//" authority path-abempty
+// authority     = [ userinfo "@" ] host [ ":" port ]
+// path-abempty  = *( "/" segment )
+//
+// That is, a hier-part of the form '/ path-absolute', '/ path-rootless' or
+// '/ path-empty' is NOT allowed here. This should be safe because we only
+// call this function for curl access, any file access would use APR.
+//
+// However, as a special exception, this function allows:
+//
+// url			= authority path-abempty
+//
+// without the 'sheme ":" "//"' parts.
+//
+// As follows from the ABNF (see RFC, Appendix A):
+// - authority is either terminated by a '/' or by the end of the string because
+//   neither userinfo, host nor port may contain a '/'.
+// - userinfo does not contain a '@', and if it exists, is always terminated by a '@'.
+// - port does not contain a ':', and if it exists is always prepended by a ':'.
+//
+//static
+std::string AIPerHostRequestQueue::extract_canonical_hostname(std::string const& url)
+{
+  std::string::size_type pos;
+  std::string::size_type authority = 0;														// Default if there is no sheme.
+  if ((pos = url.find("://")) != url.npos && pos < url.find('/')) authority = pos + 3;		// Skip the "sheme://" if any, the second find is to avoid finding a "://" as part of path-abempty.
+  std::string::size_type host = authority;													// Default if there is no userinfo.
+  if ((pos = url.find('@', authority)) != url.npos) host = pos + 1;							// Skip the "userinfo@" if any.
+  authority = url.length() - 1;																// Default last character of host if there is no path-abempty.
+  if ((pos = url.find('/', host)) != url.npos) authority = pos - 1;							// Point to last character of host.
+  std::string::size_type len = url.find_last_not_of(":0123456789", authority) - host + 1;	// Skip trailing ":port", if any.
+  std::string hostname(url, host, len);
+#if APR_CHARSET_EBCDIC
+#error Not implemented
+#else
+  // Convert hostname to lowercase in a way that we compare two hostnames equal iff libcurl does.
+  for (std::string::iterator iter = hostname.begin(); iter != hostname.end(); ++iter)
+  {
+	int c = *iter;
+	if (c >= 'A' && c <= 'Z')
+	  *iter = c + ('a' - 'A');
+  }
+#endif
+  return hostname;
+}
+
 //static
 AIPerHostRequestQueuePtr AIPerHostRequestQueue::instance(std::string const& hostname)
 {