Added support for path API request style.

Rather than using virtual host style requests, path style requests can be used
instead.

i.e. rather than bucketname.s3.amazon.com/... the s3fs will be able to request
from s3.amazon.com/bucketname/...

This is useful for S3 compatible APIs which don't support the virtual host style
request.

It is enabled with the new option, `use_path_style_request`.

Example:

    /usr/bin/s3fs data ~/netcdf -o url="https://swift.rc.nectar.org.au:8888/" -o use_path_request_style -o allow_other -o uid=500 -o gid=500

src/common.h

@@ -69,6 +69,7 @@ extern bool debug;
 extern bool foreground;
 extern bool foreground2;
 extern bool nomultipart;
+extern bool pathrequeststyle;
 extern std::string program_name;
 extern std::string service_path;
 extern std::string host;

src/s3fs.cpp

@@ -83,6 +83,7 @@ bool debug                        = false;
 bool foreground                   = false;
 bool foreground2                  = false;
 bool nomultipart                  = false;
+bool pathrequeststyle             = false;
 std::string program_name;
 std::string service_path          = "/";
 std::string host                  = "http://s3.amazonaws.com";
@@ -3674,6 +3675,10 @@ static int my_fuse_opt_proc(void* data, const char* arg, int key, struct fuse_ar
       }
       return 0;
     }
+    if(0 == strcmp(arg, "use_path_request_style")){
+      pathrequeststyle = true;
+      return 0;
+    }
 
     // debug option
     //

src/s3fs_util.cpp

@@ -967,6 +967,11 @@ void show_help (void)
     "        only rename command(ex. mv). If this option is specified with\n"
     "        nocopapi, the s3fs ignores it.\n"
     "\n"
+    "   use_path_request_style (use legacy API calling style)\n"
+    "        Enble compatibility with S3-like APIs which do not support\n"
+    "        the virtual-host request style, by using the older path request\n"
+    "        style.\n"
+    "\n"
     "FUSE/mount Options:\n"
     "\n"
     "   Most of the generic mount options described in 'man mount' are\n"

src/string_util.cpp

@@ -186,8 +186,18 @@ string prepare_url(const char* url)
     uri_length = 8;
   }
   uri  = url_str.substr(0, uri_length);
+
+  if(!pathrequeststyle){
     host = bucket + "." + url_str.substr(uri_length, bucket_pos - uri_length).c_str();
     path = url_str.substr((bucket_pos + bucket_length));
+  }else{
+    host = url_str.substr(uri_length, bucket_pos - uri_length).c_str();
+    string part = url_str.substr((bucket_pos + bucket_length));
+    if('/' != part[0]){
+      part = "/" + part;
+    }
+    path = "/" + bucket + part;
+  }
 
   url_str = uri + host + path;
 
@@ -207,4 +217,3 @@ string get_date()
   strftime(buf, sizeof(buf), "%a, %d %b %Y %H:%M:%S GMT", gmtime(&t));
   return buf;
 }
-