SnmpScalarNode.cs

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/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Martin Hentschel <info@cl-soft.de>
 *
 */

using System;
using System.Collections.Generic;
using CCodeGeneration;

namespace LwipSnmpCodeGeneration
{
    public class SnmpScalarNode: SnmpNode
    {
        protected const string LocalValueName = "v"; // name of (casted) local value variable

        private SnmpDataType dataType;
        private SnmpAccessMode accessMode;
        private readonly List<IRestriction> restrictions = new List<IRestriction>();

        private bool   useExternalMethods = false;
        private string externalGetMethod;
        private string externalTestMethod;
        private string externalSetMethod;


        public SnmpScalarNode(SnmpTreeNode parentNode)
            : base(parentNode)
        {
        }

        public override string FullNodeName
        {
            get { return this.Name + "_scalar"; }
        }

        public SnmpDataType DataType
        {
            get { return this.dataType; }
            set { this.dataType = value; }
        }

        public List<IRestriction> Restrictions
        {
            get { return this.restrictions; }
        }

        public SnmpAccessMode AccessMode
        {
            get { return this.accessMode; }
            set { this.accessMode = value; }
        }

        public virtual string FixedValueLength
        {
            get { return null; }
        }

        public virtual int OidRepresentationLen
        {
            get { return -1; }
        }

        public bool UseExternalMethods
        {
            get { return this.useExternalMethods; }
            set { this.useExternalMethods = value; }
        }

        public string ExternalGetMethod
        {
            get { return this.externalGetMethod; }
            set { this.externalGetMethod = value; }
        }
        public string ExternalTestMethod
        {
            get { return this.externalTestMethod; }
            set { this.externalTestMethod = value; }
        }
        public string ExternalSetMethod
        {
            get { return this.externalSetMethod; }
            set { this.externalSetMethod = value; }
        }

        public override void GenerateCode(MibCFile mibFile)
        {
            string getMethodName;
            string testMethodName;
            string setMethodName;

            if (this.useExternalMethods)
            {
                getMethodName  = this.externalGetMethod;
                testMethodName = this.externalTestMethod;
                setMethodName  = this.externalSetMethod;
            }
            else
            {
                getMethodName  = LwipDefs.Null;
                testMethodName = LwipDefs.Null;
                setMethodName  = LwipDefs.Null;
                
                if ((this.accessMode == SnmpAccessMode.ReadWrite) || (this.accessMode == SnmpAccessMode.ReadOnly))
                {
                    FunctionDeclaration  getMethodDecl = new FunctionDeclaration(this.Name + LwipDefs.FnctSuffix_GetValue, isStatic: true);
                    getMethodDecl.Parameter.Add(new VariableType("instance", LwipDefs.Vt_StNodeInstance, "*"));
                    getMethodDecl.Parameter.Add(new VariableType("value", VariableType.VoidString, "*"));
                    getMethodDecl.ReturnType = new VariableType(null, LwipDefs.Vt_U16);
                    mibFile.Declarations.Add(getMethodDecl);

                    Function getMethod = Function.FromDeclaration(getMethodDecl);
                    getMethodName = getMethod.Name;

                    VariableDeclaration returnValue = new VariableDeclaration((VariableType)getMethod.ReturnType.Clone());
                    returnValue.Type.Name = "value_len";
                    getMethod.Declarations.Add(returnValue);
                    getMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", getMethod.Parameter[0].Name);

                    bool valueVarUsed = false;
                    GenerateGetMethodCode(getMethod, getMethod.Parameter[1].Name, ref valueVarUsed, returnValue.Type.Name);
                    if (!valueVarUsed)
                    {
                        getMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", getMethod.Parameter[1].Name);
                    }

                    getMethod.AddCodeFormat("return {0};", returnValue.Type.Name);

                    mibFile.Implementation.Add(getMethod);
                }

                if ((this.accessMode == SnmpAccessMode.ReadWrite) || (this.accessMode == SnmpAccessMode.WriteOnly))
                {
                    bool valueVarUsed;
                    bool lenVarUsed;
                    VariableDeclaration returnValue;

                    if (this.restrictions.Count > 0)
                    {
                        FunctionDeclaration testMethodDecl = new FunctionDeclaration(this.Name + LwipDefs.FnctSuffix_SetTest, isStatic: true);
                        testMethodDecl.Parameter.Add(new VariableType("instance", LwipDefs.Vt_StNodeInstance, "*"));
                        testMethodDecl.Parameter.Add(new VariableType("len", LwipDefs.Vt_U16));
                        testMethodDecl.Parameter.Add(new VariableType("value", VariableType.VoidString, "*"));
                        testMethodDecl.ReturnType = new VariableType(null, LwipDefs.Vt_Snmp_err);
                        mibFile.Declarations.Add(testMethodDecl);

                        Function testMethod = Function.FromDeclaration(testMethodDecl);
                        testMethodName = testMethod.Name;

                        returnValue = new VariableDeclaration((VariableType)testMethod.ReturnType.Clone(), LwipDefs.Def_ErrorCode_WrongValue);
                        returnValue.Type.Name = "err";
                        testMethod.Declarations.Add(returnValue);
                        testMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", testMethod.Parameter[0].Name);

                        valueVarUsed = false;
                        lenVarUsed = false;

                        GenerateTestMethodCode(testMethod, testMethod.Parameter[2].Name, ref valueVarUsed, testMethod.Parameter[1].Name, ref lenVarUsed, returnValue.Type.Name);

                        if (!valueVarUsed)
                        {
                            testMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", testMethod.Parameter[2].Name);
                        }
                        if (!lenVarUsed)
                        {
                            testMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", testMethod.Parameter[1].Name);
                        }

                        testMethod.AddCodeFormat("return {0};", returnValue.Type.Name);

                        mibFile.Implementation.Add(testMethod);

                    }
                    else
                    {
                        testMethodName = LwipDefs.FnctName_SetTest_Ok;
                    }

                    FunctionDeclaration setMethodDecl  = null;
                    setMethodDecl = new FunctionDeclaration(this.Name + LwipDefs.FnctSuffix_SetValue, isStatic: true);
                    setMethodDecl.Parameter.Add(new VariableType("instance", LwipDefs.Vt_StNodeInstance, "*"));
                    setMethodDecl.Parameter.Add(new VariableType("len", LwipDefs.Vt_U16));
                    setMethodDecl.Parameter.Add(new VariableType("value", VariableType.VoidString, "*"));
                    setMethodDecl.ReturnType = new VariableType(null, LwipDefs.Vt_Snmp_err);
                    mibFile.Declarations.Add(setMethodDecl);

                    Function setMethod = Function.FromDeclaration(setMethodDecl);
                    setMethodName = setMethod.Name;

                    returnValue = new VariableDeclaration((VariableType)setMethod.ReturnType.Clone(), LwipDefs.Def_ErrorCode_Ok);
                    returnValue.Type.Name = "err";
                    setMethod.Declarations.Add(returnValue);
                    setMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", setMethod.Parameter[0].Name);

                    valueVarUsed = false;
                    lenVarUsed = false;

                    GenerateSetMethodCode(setMethod, setMethod.Parameter[2].Name, ref valueVarUsed, setMethod.Parameter[1].Name, ref lenVarUsed, returnValue.Type.Name);

                    if (!valueVarUsed)
                    {
                        setMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", setMethod.Parameter[2].Name);
                    }
                    if (!lenVarUsed)
                    {
                        setMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", setMethod.Parameter[1].Name);
                    }

                    setMethod.AddCodeFormat("return {0};", returnValue.Type.Name);

                    mibFile.Implementation.Add(setMethod);
                }
            }

            // create and add node declaration
            string nodeInitialization;
            if (this.accessMode == SnmpAccessMode.ReadOnly)
            {
                nodeInitialization = String.Format("SNMP_SCALAR_CREATE_NODE_READONLY({0}, {1}, {2})",
                    this.Oid,
                    LwipDefs.GetAsn1DefForSnmpDataType(this.dataType),
                    getMethodName);
            }
            else
            {
                nodeInitialization = String.Format("SNMP_SCALAR_CREATE_NODE({0}, {1}, {2}, {3}, {4}, {5})",
                    this.Oid,
                    LwipDefs.GetLwipDefForSnmpAccessMode(this.accessMode),
                    LwipDefs.GetAsn1DefForSnmpDataType(this.dataType),
                    getMethodName,
                    testMethodName,
                    setMethodName);
            }

            mibFile.Declarations.Add(new VariableDeclaration(
                new VariableType(this.FullNodeName, LwipDefs.Vt_StScalarNode, null, ConstType.Value),
                nodeInitialization, isStatic: true));
        }

        public virtual void GenerateGetMethodCode(CodeContainerBase container, string valueVarName, ref bool valueVarUsed, string retLenVarName)
        {
            bool localValueVarUsed;
            if (GenerateValueDeclaration(container, LocalValueName, valueVarName))
            {
                valueVarUsed = true;
                localValueVarUsed = false;
            }
            else
            {
                localValueVarUsed = true;  // do not generate UNUSED_ARG code
            }

            if (this.FixedValueLength == null)
            {
                // check that value with variable length fits into buffer
                container.AddElement(new Comment(String.Format("TODO: take care that value with variable length fits into buffer: ({0} <= SNMP_MAX_VALUE_SIZE)", retLenVarName), singleLine: true));
            }

            GenerateGetMethodCodeCore(container, LocalValueName, ref localValueVarUsed, retLenVarName);
            if (!localValueVarUsed)
            {
                container.AddCode(String.Format("LWIP_UNUSED_ARG({0});", LocalValueName));
            }
        }

        protected virtual void GenerateGetMethodCodeCore(CodeContainerBase container, string localValueVarName, ref bool localValueVarUsed, string retLenVarName)
        {
            container.AddElement(new Comment(String.Format("TODO: put requested value to '*{0}' here", localValueVarName), singleLine: true));
            container.AddCodeFormat("{0} = {1};", 
                retLenVarName,
                (!String.IsNullOrWhiteSpace(this.FixedValueLength)) ? this.FixedValueLength : "0");
        }

        public virtual void GenerateTestMethodCode(CodeContainerBase container, string valueVarName, ref bool valueVarUsed, string lenVarName, ref bool lenVarUsed, string retErrVarName)
        {
            if (this.Restrictions.Count > 0)
            {
                bool localVarUsed;
                if (GenerateValueDeclaration(container, LocalValueName, valueVarName))
                {
                    valueVarUsed = true;
                    localVarUsed = false;
                }
                else
                {
                    localVarUsed = true;  // do not generate UNUSED_ARG code
                }

                if (!String.IsNullOrWhiteSpace(this.FixedValueLength))
                {
                    // check for fixed value
                    container.AddCodeFormat("LWIP_ASSERT(\"Invalid length for datatype\", ({0} == {1}));", lenVarName, this.FixedValueLength);
                    lenVarUsed = true;
                }

                GenerateTestMethodCodeCore(container, LocalValueName, ref localVarUsed, lenVarName, ref lenVarUsed, retErrVarName);

                if (!localVarUsed)
                {
                    container.AddCode(String.Format("LWIP_UNUSED_ARG({0});", LocalValueName));
                }
            }
            else
            {
                container.AddCodeFormat("{0} == {1};", retErrVarName, LwipDefs.Def_ErrorCode_Ok);
            }
        }

        protected virtual void GenerateTestMethodCodeCore(CodeContainerBase container, string localValueVarName, ref bool localValueVarUsed, string lenVarName, ref bool lenVarUsed, string retErrVarName)
        {
            container.AddElement(new Comment(String.Format("TODO: test new value here:\nif (*{0} == ) {1} = {2};", localValueVarName, retErrVarName, LwipDefs.Def_ErrorCode_Ok)));
        }

        public virtual void GenerateSetMethodCode(CodeContainerBase container, string valueVarName, ref bool valueVarUsed, string lenVarName, ref bool lenVarUsed, string retErrVarName)
        {
            bool localVarUsed;
            if (GenerateValueDeclaration(container, LocalValueName, valueVarName))
            {
                valueVarUsed = true;
                localVarUsed = false;
            }
            else
            {
                localVarUsed = true; // do not generate UNUSED_ARG code
            }

            GenerateSetMethodCodeCore(container, LocalValueName, ref localVarUsed, lenVarName, ref lenVarUsed, retErrVarName);

            if (!localVarUsed)
            {
                container.AddCode(String.Format("LWIP_UNUSED_ARG({0});", LocalValueName));
            }
        }

        protected virtual void GenerateSetMethodCodeCore(CodeContainerBase container, string localValueVarName, ref bool localValueVarUsed, string lenVarName, ref bool lenVarUsed, string retErrVarName)
        {
            container.AddElement(new Comment(String.Format("TODO: store new value contained in '*{0}' here", localValueVarName), singleLine: true)); 
        }


        protected virtual bool GenerateValueDeclaration(CodeContainerBase container, string variableName, string sourceName)
        {
            container.AddDeclaration(new VariableDeclaration(
                new VariableType(variableName, LwipDefs.Vt_U8, "*"),
                "(" + new VariableType(null, LwipDefs.Vt_U8, "*") + ")" + sourceName));

            return true;
        }

        public static SnmpScalarNode CreateFromDatatype(SnmpDataType dataType, SnmpTreeNode parentNode)
        {
            switch (dataType)
            {
                case SnmpDataType.Integer:
                    return new SnmpScalarNodeInt(parentNode);

                case SnmpDataType.Gauge:
                case SnmpDataType.Counter:
                case SnmpDataType.TimeTicks:
                    return new SnmpScalarNodeUint(dataType, parentNode);
            }

            return new SnmpScalarNode(parentNode);
        }
    }
}