Ticket #14413: test-bmsg-previous-delete.cpp

/*
 * Copyright 2018, Marcin Konicki <shard@neoni.net>
 * All rights reserved. Distributed under the terms of the MIT license.
 *
 * Build it with: g++ -o testApp -lbe test-bmsg-previous-delete.cpp
 *
 * Run either:
 * - testApp -i (safe)
 * - testApp -d (crash)
 * - testApp (usage info)
 */
#include <Application.h>
#include <stdio.h>

class TestApp : public BApplication
{
public:
    TestApp();
    ~TestApp();

    thread_id Run(bool deletePrevious = true);
    void MessageReceived(BMessage* msg);
};

TestApp::TestApp()
    :
    BApplication("application/x-vnd.Test.DeletePreiousMessage")
{
}

TestApp::~TestApp()
{
}

thread_id
TestApp::Run(bool deletePrevious)
{
    BMessage request('test');
    request.AddInt32("step", 1);
    printf("\tTesting BMessage::Previous %s deleting returned message\n",
        deletePrevious ? "WITH" : "WITHOUT");
    request.AddBool("deletePrevious", deletePrevious);
    printf("\tSending test message with need for a reply... ");
    PostMessage(&request, this, this);
    printf("done\n");
    return BApplication::Run();
}

void
TestApp::MessageReceived(BMessage* msg)
{
    printf("\n\tReceived message\n");
    msg->PrintToStream();
    if (msg->what != 'test') {
        printf("\tUnknown message, pass over to BApplication and return\n");
        BApplication::MessageReceived(msg);
        return;
    }

    if (msg->GetInt32("step", 0) == 1) {
        printf("\tGot request for a reply\n");
        BMessage reply('test');
        reply.AddInt32("step", 2);
        printf("\tSend reply... ");
        msg->SendReply(&reply);
        printf("done\n");
        printf("\tReturn\n");
        return;
    }

    if (msg->IsReply() && msg->GetInt32("step", 0) == 2) {
        printf("\tGot reply\n");
        const BMessage* previous = msg->Previous();
        if (previous && previous->GetInt32("step", 0) == 1) {
            printf("\tFound previous BMessage* with correct step number\n");
            if (previous->GetBool("deletePrevious", true)) {
                printf("\tDeleting previous as advised by documentation\n");
                delete previous;
            } else
                printf(
                    "\tLeaving previous, hoping it will be deleted by API\n");

            printf("\tTest complete, posting B_QUIT_REQUESTED to quit... ");
            PostMessage(B_QUIT_REQUESTED);
            printf("done\n");
            printf("\tReturn\n");
            return;
        }

        printf("\tPrevious not found or did not contain correct step number\n");
        printf("\tReturn\n");
        return;
    }

    printf("\tHow did we get here? Anyway, pass message over to BApplication "
           "and return\n");
    BApplication::MessageReceived(msg);
}

void
PrintUsage()
{
    printf(
        ""
        "Usage: testApp [option]\n"
        "Options:\n"
        "\t-h   print this usage info\n"
        "\t-d   delete BMessage returned from BMessage::Previous\n"
        "\t-i   ignore documentation and leave returned object to the API\n"
        "\n"
        "It runs test application which sends message to itself and then "
        "replies to it.\n"
        "After receiving reply, it gets result of BMessage->Previous() and, "
        "depending \n"
        "on option passed to it, deletes result or not.\n"
        "Documentation mentions that result SHOULD be deleted by the caller:\n"
        "https://www.haiku-os.org/docs/api/"
        "classBMessage.html#a57c84d02e54ef19fd1516d9bf7e3fe45\n"
        "But when we do that on Haiku, application crashes. That suggests "
        "that, unlike\n"
        "described in documentation, Haiku does not return a COPY of previous "
        "message.\n"
        "Instead it seems to return a pointer to ORIGINAL BMessage.\n");
}

int
main(int argc, char** argv)
{
    if (argc <= 1 || argv[1][0] != '-' || argv[1][1] == 'h') {
        PrintUsage();
        return B_NO_ERROR;
    }

    bool deletePrevious = argv[1][1] == 'd';

    printf("Creating TestApp... ");
    TestApp* app = new TestApp();
    printf("done\n");
    printf("Calling TestApp->Run()\n");
    app->Run(deletePrevious);
    printf("... done.\nDeleting TestApp... ");
    delete app;
    printf("done.\nBye bye!\n");

    return B_NO_ERROR;
}