RpcReader - read RPC requests from a client
An RpcReader reads RPC requests from an rpcstream which represents a connection
to a client. When it reads an RPC request, it uses the request number to look
up the address of a function in an array and calls that function to unmarshall
the request's arguments and execute the request.
An RpcReader is not instantiable; you have to implement a derived class which
initializes the function array with addresses of static member functions to
unmarshall RPC requests and which defines the action to be performed when the
client closes the connection. The function array looks like this:
typedef void (*PF)(RpcReader*, RpcHdr&, rpcstream&);
Each function stored in the array should extract any arguments needed by the RPC
request from the rpcstream, execute the RPC request, and insert any return
values into the rpcstream so they can be sent back to the client.
- RpcReader(rpcstream* client, int nfcns)
- RpcReader(int fd, int nfcns, boolean binary =
- If given a non-nil rpcstream, prepare to read RPC requests
from the client using it. If given a nil rpcstream, just allocate the
function array. If given a file descriptor, create a new rpcstream and
prepare to read RPC requests from the client using it. ``nfcns'' sets the
size of the function array that each constructor allocates.
- virtual int inputReady(int)
- Read an RPC request (only one request per call so the
program can service RPC requests from multiple connections in round robin
fashion). Look up the appropriate function in the reader's or another
reader's function array and call it to handle the RPC request. Return the
appropriate status to tell the Dispatcher whether to detach the RpcReader,
call inputReady again, or wait for new data before calling inputReady
again. A derived class should not need to redefine this function.
- virtual RpcReader* map(unsigned long reader)
- You can redefine this function to change which reader
executes an RPC request after it's read. Ordinarily the same reader that
reads an RPC request also executes it, but you can hand the request off to
another reader as well.
- virtual void connectionClosed(int fd) = 0
- You have to define this function since it may be your only
chance to perform cleanup (such as deleting this) when the client closes
RpcHdr(3I), RpcService(3I), rpcstream(3I)