Mediator_Exercise.c

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#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include "helpers/stringlist.h"
#include "helpers/dynamicstring.h"
 
#include "Mediator_Functions.h"
#include "Mediator_Exercise.h"
 
//=============================================================================
//=============================================================================
 
static bool _ListToString(StringList* items, DynamicString* output)
{
    bool success = false;
 
    if (items != NULL && output != NULL)
    {
        success = true;
        for (size_t index = 0; index < items->strings_count; ++index)
        {
            if (index != 0)
            {
                success = DynamicString_Append(output, ", ");
            }
            if (success)
            {
                success = DynamicString_Append(output, items->strings[index]);
            }
 
            if (!success)
            {
                printf("  Error!  Out of memory condition converting a list of strings to a comma-delimited string in _ListToString()!\n");
                break;
            }
        }
    }
 
    return success;
}
 
static const char* _GetMediatorErrorMessage(MediatorErrorCode errorCode)
{
    const char* msg = "";
 
    switch (errorCode)
    {
        case MediatorErrorCode_Group_Does_Not_Exist:
            msg = "Group does not exist";
            break;
 
        case MediatorErrorCode_User_Does_Not_Exist:
            msg = "User does not exist";
            break;
 
        case MediatorErrorCode_Null_Argument:
            msg = "Null argument";
            break;
 
        case MediatorErrorCode_No_Memory:
            msg = "Out of memory";
            break;
 
        case MediatorErrorCode_No_Error:
            msg = "No error";
            break;
 
        default:
            msg = "Unknown error";
            break;
    }
 
    return msg;
}
 
static void _ReportAnyMediatorError(const char *prompt, MediatorErrorCode errorCode)
{
    if (errorCode != MediatorErrorCode_No_Error)
    {
        const char* msg = _GetMediatorErrorMessage(errorCode);
        if (prompt == NULL)
        {
            prompt = "Unknown operation";
        }
        printf("  Error!  %s: %s!\n", prompt, msg);
    }
}
 
 
static bool Mediator_SetupUsers(void)
{
    MediatorErrorCode errorCode;
    // Operation 12: Add a user
    errorCode = Mediator_AddUser("Stephen");
    _ReportAnyMediatorError("Adding user \"Stephen\"", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUser("Gladys");
        _ReportAnyMediatorError("Adding user \"Gladys\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUser("Marvin");
        _ReportAnyMediatorError("Adding user \"Marvin\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUser("Arthur");
        _ReportAnyMediatorError("Adding user \"Arthur\"", errorCode);
    }
 
    return errorCode == MediatorErrorCode_No_Error;
}
 
static bool Mediator_SetupGroups(void)
{
    MediatorErrorCode errorCode;
    // Operation 10: Add a group
    errorCode = Mediator_AddGroup("admins");
    _ReportAnyMediatorError("Adding group \"admin\"", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddGroup("Users");
        _ReportAnyMediatorError("Adding group \"Users\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddGroup("Power Users");
        _ReportAnyMediatorError("Adding group \"Power Users\"", errorCode);
    }
 
    // Operation 7: Add user to a group
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Marvin", "admins");
        _ReportAnyMediatorError("Adding \"Marvin\" to \"admin\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Arthur", "admins");
        _ReportAnyMediatorError("Adding \"Arthur\" to \"admin\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Stephen", "Users");
        _ReportAnyMediatorError("Adding \"Stephen\" to \"Users\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Gladys", "Users");
        _ReportAnyMediatorError("Adding \"Gladys\" to \"Users\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Arthur", "Power Users");
        _ReportAnyMediatorError("Adding \"Arthur\" to \"Power Users\"", errorCode);
    }
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_AddUserToGroup("Marvin", "Power Users");
        _ReportAnyMediatorError("Adding \"Marvin\" to \"Power Users\"", errorCode);
    }
 
    return errorCode == MediatorErrorCode_No_Error;
}
 
static bool _Mediator_Example_ShowAllGroups(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    MediatorErrorCode errorCode;
    //-----------------------------------------------------------------
    // Operation 1: Determine all groups
    errorCode = Mediator_GetAllGroups(&groupNames);
    _ReportAnyMediatorError("Getting all groups", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        canContinue = _ListToString(&groupNames, &output);
        if (canContinue)
        {
            printf("  Operation 1: Show all groups\n");
            printf("    All groups: %s\n", output.string);
        }
        DynamicString_Clear(&output);
        StringList_Clear(&groupNames);
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_ShowAllUsers(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList userNames = { 0 };
    MediatorErrorCode errorCode;
    //-----------------------------------------------------------------
    // Operation 2: Determine all users
    errorCode = Mediator_GetAllUsers(&userNames);
    _ReportAnyMediatorError("Getting all users", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        canContinue = _ListToString(&userNames, &output);
        if (canContinue)
        {
            printf("  Operation 2: Show all users\n");
            printf("    All users : %s\n", output.string);
        }
        DynamicString_Clear(&output);
        StringList_Clear(&userNames);
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_SeeIfUserInGroup(void)
{
    bool canContinue = true;
    const char* userName = "Arthur";
    const char* groupName = "admins";
    // Operation 3: Does a user belong to a group
    printf("  Operation 3: Determine if a user is a member of a specific group.\n");
    printf("    Is user '%s' in the '%s' group?", userName, groupName);
    printf("  %s\n", Mediator_IsUserInGroup(userName, groupName) ? "Yes" : "No");
 
    return canContinue;
}
 
static bool _Mediator_Example_ShowUsersInGroup(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList userNames = { 0 };
    const char* groupName = "Users";
    MediatorErrorCode errorCode;
    // Operation 4: Show all users in a group
    printf("  Operation 4: Show all users in a specific group.\n");
    errorCode = Mediator_GetUsersInGroup(groupName, &userNames);
    _ReportAnyMediatorError("Getting all users in a group", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        canContinue = _ListToString(&userNames, &output);
        if (canContinue)
        {
            printf("    All users in '%s' group: %s\n", groupName, output.string);
        }
        DynamicString_Clear(&output);
        StringList_Clear(&userNames);
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_ShowAllGroupsContainingUser(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    const char* userName = "Marvin";
    MediatorErrorCode errorCode;
    // Operation 5: Show all groups with a user
    printf("  Operation 5: Show all groups containing a specific user.\n");
    errorCode = Mediator_GetGroupsWithUser(userName, &groupNames);
    _ReportAnyMediatorError("Getting all groups containing a user", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        canContinue = _ListToString(&groupNames, &output);
        if (canContinue)
        {
            printf("    All groups with user '%s': %s\n", userName, output.string);
        }
        DynamicString_Clear(&output);
        StringList_Clear(&groupNames);
    }
 
    return canContinue;
}
 
 
static bool _Mediator_Example_RemoveUserFromGroup(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    const char* userName = "Marvin";
    const char* groupName = "Power Users";
    MediatorErrorCode errorCode;
    // Operation 6: Show Remove a user from a group
    printf("  Operation 6: Remove a user from a group.\n");
    errorCode = Mediator_RemoveUserFromGroup(userName, groupName);
    _ReportAnyMediatorError("Removing user from a group", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        printf("    Removed user '%s' from group '%s'\n", userName, groupName);
        errorCode = Mediator_GetGroupsWithUser(userName, &groupNames);
        _ReportAnyMediatorError("Getting groups with a user", errorCode);
        if (errorCode == MediatorErrorCode_No_Error)
        {
            canContinue = _ListToString(&groupNames, &output);
            if (canContinue)
            {
                printf("      All groups with user '%s': %s\n", userName, output.string);
            }
            DynamicString_Clear(&output);
            StringList_Clear(&groupNames);
        }
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_AddUserToGroup(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    const char* userName = "Marvin";
    const char* groupName = "Users";
    MediatorErrorCode errorCode;
    // Operation 7: Add a user to a group
    printf("  Operation 7: Add a user to a group.\n");
    printf("    Adding user '%s' to group '%s'.\n", userName, groupName);
    errorCode = Mediator_AddUserToGroup(userName, groupName);
    _ReportAnyMediatorError("Adding user to a group", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_GetGroupsWithUser(userName, &groupNames);
        _ReportAnyMediatorError("Getting groups with a user", errorCode);
        if (errorCode == MediatorErrorCode_No_Error)
        {
            canContinue = _ListToString(&groupNames, &output);
            if (canContinue)
            {
                printf("      All groups with user '%s': %s\n", userName, output.string);
            }
            DynamicString_Clear(&output);
            StringList_Clear(&groupNames);
        }
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_RemoveUserFromAllGroups(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    const char* userName = "Arthur";
    MediatorErrorCode errorCode;
    // Operation 8: Remove a user from all groups
    printf("  Operation 8: Remove a user from all groups.\n");
    errorCode = Mediator_GetGroupsWithUser(userName, &groupNames);
    _ReportAnyMediatorError("Getting groups with a user before removing user", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        canContinue = _ListToString(&groupNames, &output);
        if (canContinue)
        {
            printf("    Removing user '%s' from all groups.\n", userName);
            printf("      Start: all groups with user '%s': %s\n", userName, output.string);
            DynamicString_Clear(&output);
            StringList_Clear(&groupNames);
            printf("      Removing...\n");
            errorCode = Mediator_RemoveUserFromAllGroups(userName);
            _ReportAnyMediatorError("Removing user from all groups", errorCode);
            if (errorCode == MediatorErrorCode_No_Error)
            {
                errorCode = Mediator_GetGroupsWithUser(userName, &groupNames);
                _ReportAnyMediatorError("Getting groups with a user after removing user", errorCode);
                if (errorCode == MediatorErrorCode_No_Error)
                {
                    canContinue = _ListToString(&groupNames, &output);
                    if (canContinue)
                    {
                        printf("      End: all groups with user '%s': %s\n", userName, output.string);
                    }
                    DynamicString_Clear(&output);
                    StringList_Clear(&groupNames);
                }
            }
        }
    }
 
    return canContinue;
}
 
static bool _Mediator_Example_RemoveUser(void)
{
    bool canContinue = false;
    DynamicString output = { 0 };
    StringList groupNames = { 0 };
    StringList userNames = { 0 };
    const char* userName = "Marvin";
    MediatorErrorCode errorCode;
    // Operation 9: Remove a user (which also removes user from all groups)
    printf("  Operation 9: Remove a user (also removes the user from all groups).\n");
    printf("    Removing user '%s'.\n", userName);
    errorCode = Mediator_RemoveUser(userName);
    _ReportAnyMediatorError("Removing a user", errorCode);
    if (errorCode == MediatorErrorCode_No_Error)
    {
        errorCode = Mediator_GetAllUsers(&userNames);
        _ReportAnyMediatorError("Getting all users after removing a user", errorCode);
        if (errorCode == MediatorErrorCode_No_Error)
        {
            canContinue = _ListToString(&userNames, &output);
            if (canContinue)
            {
                printf("      All users : %s\n", output.string);
            }
            DynamicString_Clear(&output);
            StringList_Clear(&userNames);
        }
    }
 
    if (errorCode == MediatorErrorCode_No_Error && canContinue)
    {
        errorCode = Mediator_GetAllGroups(&groupNames);
        _ReportAnyMediatorError("Getting all groups after removing a user", errorCode);
        if (errorCode == MediatorErrorCode_No_Error)
        {
            for (size_t index = 0; index < groupNames.strings_count; index++)
            {
                const char* name = groupNames.strings[index];
                errorCode = Mediator_GetUsersInGroup(name, &userNames);
                _ReportAnyMediatorError("Getting users in a group after removing a user", errorCode);
                if (errorCode == MediatorErrorCode_No_Error)
                {
                    canContinue = _ListToString(&userNames, &output);
                    if (canContinue)
                    {
                        printf("      Users in group '%s': %s\n", name, output.string);
                    }
                    DynamicString_Clear(&output);
                    StringList_Clear(&userNames);
                    if (!canContinue)
                    {
                        break;
                    }
                }
                else
                {
                    canContinue = false;
                    break;
                }
            }
        }
    }
 
    return canContinue;
}
 
//=============================================================================
//=============================================================================
 
// ! [Using Mediator in C]
void Mediator_Exercise(void)
{
    printf("\nMediator Exercise\n");
 
    bool canContinue = Mediator_SetupUsers();
    if (canContinue)
    {
        canContinue = Mediator_SetupGroups();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_ShowAllGroups();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_ShowAllUsers();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_SeeIfUserInGroup();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_ShowUsersInGroup();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_ShowAllGroupsContainingUser();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_RemoveUserFromGroup();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_AddUserToGroup();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_RemoveUserFromAllGroups();
    }
 
    if (canContinue)
    {
        canContinue = _Mediator_Example_RemoveUser();
    }
    //-----------------------------------------------------------------
 
    // Clean-up
    Mediator_ClearAll();
 
    printf("  Done.\n");
}
// ! [Using Mediator in C]