This program illustrates how to implement a simple client and server
using CORBA, IIOP, and asynchronous method invocations (AMI).  Client
applications can use this service to download and display files from a
CORBA server on the network.  The core functionality of this program
is as follows:

        * Client applications will use an iterator in conjunction with AMI
          to download and display files from multiple CORBA server one
          ``chunk'' at a time simultaneously, without requiring
          multiple threads.  This design will help improve the memory
          management overhead on the client and server.

        * Operations in the IDL interface will use exceptions to propagate
          problems back to clients.

        * The CORBA Naming Service is used to bind and resolve object
          references, rather than using a file.
    
The client program performs the following activities:
          
        1. From the command-line, it reads the name of the pathname
           you want to download.  It then initializes the client-side
           ORB and uses resolve_initial_references() to obtain a
           reference to a Naming Service (which must be running). This
           object reference is then downcast via _narrow() to an
           object reference for a CosNaming::NamingContext interface,
           which is then used to resolve the object reference that the
           server bound earlier.  After narrowing this to the Server
           interface, the get_iterator() operation is called via the
           object reference to obtain the Chunk_Iterator, which is
           used to download the file.
          
        2. The client invokes the sendc_next_chunk() method on the
           iterator, passing in the offset and the object reference to
           the client's reply handler.  Only one pending call at a
           time per-server.  To relax this constraint would require
           some type of offset parameter to the next_chunk() callback
           to perform reassembly if chunks for the same file arrived
           out of order.
          
        3. When next_chunk() returns a chunk of the file, the contents
           are written into a temporary file created in your a cache
           (e.g., /tmp/yourloginname) on the local host.  Then, an
           external viewer is spawned to display the file.  The type
           of viewer to spawn is determined by examining the the
           content_type_ metadata returned by the server.
       
The example can be run as follows:

	1. Start the Name Service:

		$ NameService -o /tmp/ns.ior

	2. Start the SMI Content Server:

		$ server -ORBInitRef NameService=file:///tmp/ns.ior

	3. Request a file using the client:

		$ client -ORBInitRef NameService=file:///tmp/ns.ior \
		~/foo.jpg ~/bar.jpg

This example can service multiple file requests.

----------------------------------------

The server output should look like the following:

$ ./server -ORBInitRef NameService=file:///tmp/ns.ior
Bound <Iterator_Factory> to <IOR:010000002400000049444c3a57653625f5365727665722f4974657261746f725f466163746f72793a312e300001000000000000007c000000010102001400000076616c696e6f12722e6563652e7563692e65647500f39600001b00000014010f00525354bd9d4e39a6ac03000000000001000000010000000003000000000000000800000001000000004f4154010000001400000001ad85e4001000100000000000901010000000000004f41540400000001ac0000> in Name Service.
Accepting requests.
Received request for file: </home/myhome/foo.jpg>
Sending chunk 1 at offset <0> of size <8192>
Received request for file: </home/myhome/bar.jpg>
Sending chunk 2 at offset <8192> of size <8192>
Sending chunk 1 at offset <0> of size <8192>
Sending chunk 3 at offset <16384> of size <8192>
Sending chunk 4 at offset <24576> of size <8192>
Sending chunk 2 at offset <8192> of size <8192>
Sending chunk 5 at offset <32768> of size <4573>
Sending chunk 3 at offset <16384> of size <8192>
Sending chunk 4 at offset <24576> of size <8192>
Sending chunk 5 at offset <32768> of size <6997>

Notice that requests for chunks of data from two separate files occur
in the above run.

----------------------------------------

The client output should look similar to:

$ ./client -ORBInitRef NameService=file:///tmp/ns.ior ~/foo.jpg ~/bar.jpg
Wrote retrieved data to file </tmp/ace-file-nBqLM2>
Spawned viewer <xv> with PID <11134>.
Wrote retrieved data to file </tmp/ace-file-MKURUU>
Spawned viewer <xv> with PID <11135>.