IPDL/Five minute example

This page walks you through the steps of creating an IPDL protocol and writing the C++ code that implements the required interfaces. This guide walks you through the steps taken to implement the testing code in ipc/ipdl/test-harness. You are encouraged to follow this guide step-by-step and change the code in ipc/ipdl/test-harness as you follow along.

Write the IPDL specification

Put this in the file ipc/ipdl/test-harness/Test.ipdl.

sync protocol Test
{
both:
    sync Ping() returns (int status);

parent:
    GetValue(String key);
    GetValues(StringArray keys);
    sync SetValue(String key, String val) returns (bool ok);

child:
    TellValue(String key, String val);
    TellValues(StringArray keys, StringArray vals);

state START:
    recv Ping goto START;
    send Ping goto START;

    recv SetValue goto HAVE_VALUES;

state HAVE_VALUES:
    recv Ping goto HAVE_VALUES;
    send Ping goto HAVE_VALUES;

    recv SetValue goto HAVE_VALUES;

    recv GetValue goto TELLING_VALUE;
    recv GetValues goto TELLING_VALUES;

state TELLING_VALUE:
    send TellValue goto HAVE_VALUES;
state TELLING_VALUES:
    send TellValues goto HAVE_VALUES;
};

Hook the IPDL file into our build system

• Add ipc/ipdl/test-harness to the IPDLDIRS variable in ipc/ipdl/Makefile.in
• Create the file ipc/ipdl/test-harness/ipdl.mk and add the following text to it.

IPDLSRCS = \
  Test.ipdl \
  $(NULL)