SnmpTableNode.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 System.Text;
using CCodeGeneration;

namespace LwipSnmpCodeGeneration
{
    public class SnmpTableNode: SnmpScalarAggregationNode
    {
        private readonly List<SnmpScalarNode> cellNodes = new List<SnmpScalarNode>();
        private readonly List<SnmpScalarNode> indexNodes = new List<SnmpScalarNode>();
        private string augmentedTableRow = null;


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

        public List<SnmpScalarNode> CellNodes
        {
            get { return cellNodes; }
        }

        public List<SnmpScalarNode> IndexNodes
        {
            get { return indexNodes; }
        }

        public string AugmentedTableRow
        {
            get { return this.augmentedTableRow; }
            set { this.augmentedTableRow = value; }
        }

        public override string FullNodeName
        {
            get
            {
                string result = this.Name.ToLowerInvariant();
                if (!result.Contains("table"))
                {
                    result += "_table";
                }

                return result;              
            }
        }

        protected override IEnumerable<SnmpScalarNode> AggregatedScalarNodes
        {
            get { return this.cellNodes; }
        }

        public override void GenerateCode(MibCFile mibFile)
        {
            FunctionDeclaration getInstanceMethodDecl = new FunctionDeclaration(this.FullNodeName + LwipDefs.FnctSuffix_GetInstance, isStatic: true);
            getInstanceMethodDecl.Parameter.Add(new VariableType("column", LwipDefs.Vt_U32, "*", ConstType.Value));
            getInstanceMethodDecl.Parameter.Add(new VariableType("row_oid", LwipDefs.Vt_U32, "*", ConstType.Value));
            getInstanceMethodDecl.Parameter.Add(new VariableType("row_oid_len", LwipDefs.Vt_U8, ""));
            getInstanceMethodDecl.Parameter.Add(new VariableType("cell_instance", LwipDefs.Vt_StNodeInstance, "*"));
            getInstanceMethodDecl.ReturnType = new VariableType(null, LwipDefs.Vt_Snmp_err);
            mibFile.Declarations.Add(getInstanceMethodDecl);

            Function getInstanceMethod = Function.FromDeclaration(getInstanceMethodDecl);
            GenerateGetInstanceMethodCode(getInstanceMethod);
            mibFile.Implementation.Add(getInstanceMethod);


            FunctionDeclaration getNextInstanceMethodDecl = new FunctionDeclaration(this.FullNodeName + LwipDefs.FnctSuffix_GetNextInstance, isStatic: true);
            getNextInstanceMethodDecl.Parameter.Add(new VariableType("column", LwipDefs.Vt_U32, "*", ConstType.Value));
            getNextInstanceMethodDecl.Parameter.Add(new VariableType("row_oid", LwipDefs.Vt_StObjectId, "*"));
            getNextInstanceMethodDecl.Parameter.Add(new VariableType("cell_instance", LwipDefs.Vt_StNodeInstance, "*"));
            getNextInstanceMethodDecl.ReturnType = new VariableType(null, LwipDefs.Vt_Snmp_err);
            mibFile.Declarations.Add(getNextInstanceMethodDecl);

            Function getNextInstanceMethod = Function.FromDeclaration(getNextInstanceMethodDecl);
            GenerateGetNextInstanceMethodCode(getNextInstanceMethod);
            mibFile.Implementation.Add(getNextInstanceMethod);

            
            VariableType instanceType = new VariableType("cell_instance", LwipDefs.Vt_StNodeInstance, "*");
            GenerateAggregatedCode(
                mibFile,
                instanceType,
                String.Format("SNMP_TABLE_GET_COLUMN_FROM_OID({0}->instance_oid.id)", instanceType.Name));


            #region create and add column/table definitions

            StringBuilder colDefs = new StringBuilder();
            foreach (SnmpScalarNode colNode in this.cellNodes)
            {
                colDefs.AppendFormat("  {{{0}, {1}, {2}}}, /* {3} */ \n",
                    colNode.Oid,
                    LwipDefs.GetAsn1DefForSnmpDataType(colNode.DataType),
                    LwipDefs.GetLwipDefForSnmpAccessMode(colNode.AccessMode),
                    colNode.Name);
            }
            if (colDefs.Length > 0)
            {
                colDefs.Length--;
            }

            VariableDeclaration colDefsDecl = new VariableDeclaration(
                new VariableType(this.FullNodeName + "_columns", LwipDefs.Vt_StTableColumnDef, null, ConstType.Value, String.Empty),
                "{\n" + colDefs + "\n}",
                isStatic: true);

            mibFile.Declarations.Add(colDefsDecl);

            string nodeInitialization = String.Format("SNMP_TABLE_CREATE({0}, {1}, {2}, {3}, {4}, {5}, {6})",
                this.Oid,
                colDefsDecl.Type.Name,
                getInstanceMethodDecl.Name, getNextInstanceMethodDecl.Name,
                (this.GetMethodRequired) ? this.GetMethodName : LwipDefs.Null,
                (this.TestMethodRequired) ? this.TestMethodName : LwipDefs.Null,
                (this.SetMethodRequired) ? this.SetMethodName : LwipDefs.Null
                );

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

        protected virtual void GenerateGetInstanceMethodCode(Function getInstanceMethod)
        {
            VariableDeclaration returnValue = new VariableDeclaration((VariableType)getInstanceMethod.ReturnType.Clone(), LwipDefs.Def_ErrorCode_NoSuchInstance);
            returnValue.Type.Name = "err";
            getInstanceMethod.Declarations.Add(returnValue);

            int instanceOidLength = 0;
            StringBuilder indexColumns = new StringBuilder();
            foreach (SnmpScalarNode indexNode in this.indexNodes)
            {
                if (instanceOidLength >= 0)
                {
                    if (indexNode.OidRepresentationLen >= 0)
                    {
                        instanceOidLength += indexNode.OidRepresentationLen;
                    }
                    else
                    {
                        // at least one index column has a variable length -> we cannot perform a static check
                        instanceOidLength = -1;
                    }
                }

                indexColumns.AppendFormat(
                    " {0} ({1}, OID length = {2})\n",
                    indexNode.Name,
                    indexNode.DataType,
                    (indexNode.OidRepresentationLen >= 0) ? indexNode.OidRepresentationLen.ToString() : "variable");
            }
            if (indexColumns.Length > 0)
            {
                indexColumns.Length--;

                getInstanceMethod.Declarations.Insert(0, new Comment(String.Format(
                    "The instance OID of this table consists of following (index) column(s):\n{0}",
                    indexColumns)));
            }

            string augmentsHint = "";
            if (!String.IsNullOrWhiteSpace(this.augmentedTableRow))
            {
                augmentsHint = String.Format(
                    "This table augments table '{0}'! Index columns therefore belong to table '{0}'!\n" + 
                    "You may simply call the '*{1}' method of this table.\n\n",
                    (this.augmentedTableRow.ToLowerInvariant().EndsWith("entry")) ? this.augmentedTableRow.Substring(0, this.augmentedTableRow.Length-5) : this.augmentedTableRow,
                    LwipDefs.FnctSuffix_GetInstance);
            }

            CodeContainerBase ccb = getInstanceMethod;
            if (instanceOidLength > 0)
            {
                IfThenElse ite = new IfThenElse(String.Format("{0} == {1}", getInstanceMethod.Parameter[2].Name, instanceOidLength));
                getInstanceMethod.AddElement(ite);
                ccb = ite;
            }

            ccb.AddCodeFormat("LWIP_UNUSED_ARG({0});", getInstanceMethod.Parameter[0].Name);
            ccb.AddCodeFormat("LWIP_UNUSED_ARG({0});", getInstanceMethod.Parameter[1].Name);
            if (instanceOidLength <= 0)
            {
                ccb.AddCodeFormat("LWIP_UNUSED_ARG({0});", getInstanceMethod.Parameter[2].Name);
            }
            ccb.AddCodeFormat("LWIP_UNUSED_ARG({0});", getInstanceMethod.Parameter[3].Name);

            ccb.AddElement(new Comment(String.Format(
                "TODO: check if '{0}'/'{1}' params contain a valid instance oid for a row\n" +
                "If so, set '{2} = {3};'\n\n" + 
                "snmp_oid_* methods may be used for easier processing of oid\n\n" + 
                "{4}" + 
                "In order to avoid decoding OID a second time in subsequent get_value/set_test/set_value methods,\n" +
                "you may store an arbitrary value (like a pointer to target value object) in '{5}->reference'/'{5}->reference_len'.\n" +
                "But be aware that not always a subsequent method is called -> Do NOT allocate memory here and try to release it in subsequent methods!\n\n" +
                "You also may replace function pointers in '{5}' param for get/test/set methods which contain the default values from table definition,\n" +
                "in order to provide special methods, for the currently processed cell. Changed pointers are only valid for current request.",
                getInstanceMethod.Parameter[1].Name,
                getInstanceMethod.Parameter[2].Name,
                returnValue.Type.Name,
                LwipDefs.Def_ErrorCode_Ok,
                augmentsHint,
                getInstanceMethod.Parameter[3].Name
                )));

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

        protected virtual void GenerateGetNextInstanceMethodCode(Function getNextInstanceMethod)
        {
            getNextInstanceMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", getNextInstanceMethod.Parameter[0].Name);
            getNextInstanceMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", getNextInstanceMethod.Parameter[1].Name);
            getNextInstanceMethod.AddCodeFormat("LWIP_UNUSED_ARG({0});", getNextInstanceMethod.Parameter[2].Name);

            VariableDeclaration returnValue = new VariableDeclaration((VariableType)getNextInstanceMethod.ReturnType.Clone(), LwipDefs.Def_ErrorCode_NoSuchInstance);
            returnValue.Type.Name = "err";
            getNextInstanceMethod.Declarations.Add(returnValue);

            StringBuilder indexColumns = new StringBuilder();
            foreach (SnmpScalarNode indexNode in this.indexNodes)
            {
                indexColumns.AppendFormat(
                    " {0} ({1}, OID length = {2})\n",
                    indexNode.Name,
                    indexNode.DataType,
                    (indexNode.OidRepresentationLen >= 0) ? indexNode.OidRepresentationLen.ToString() : "variable");
            }
            if (indexColumns.Length > 0)
            {
                indexColumns.Length--;

                getNextInstanceMethod.Declarations.Insert(0, new Comment(String.Format(
                    "The instance OID of this table consists of following (index) column(s):\n{0}",
                    indexColumns)));
            }

            string augmentsHint = "";
            if (!String.IsNullOrWhiteSpace(this.augmentedTableRow))
            {
                augmentsHint = String.Format(
                    "This table augments table '{0}'! Index columns therefore belong to table '{0}'!\n" + 
                    "You may simply call the '*{1}' method of this table.\n\n",
                    (this.augmentedTableRow.ToLowerInvariant().EndsWith("entry")) ? this.augmentedTableRow.Substring(0, this.augmentedTableRow.Length-5) : this.augmentedTableRow,
                    LwipDefs.FnctSuffix_GetNextInstance);
            }

            getNextInstanceMethod.AddElement(new Comment(String.Format(
                "TODO: analyze '{0}->id'/'{0}->len' and return the subsequent row instance\n" +
                "Be aware that '{0}->id'/'{0}->len' must not point to a valid instance or have correct instance length.\n" +
                "If '{0}->len' is 0, return the first instance. If '{0}->len' is longer than expected, cut superfluous OID parts.\n" +
                "If a valid next instance is found, store it in '{0}->id'/'{0}->len' and set '{1} = {2};'\n\n" + 
                "snmp_oid_* methods may be used for easier processing of oid\n\n" + 
                "{3}" + 
                "In order to avoid decoding OID a second time in subsequent get_value/set_test/set_value methods,\n" +
                "you may store an arbitrary value (like a pointer to target value object) in '{4}->reference'/'{4}->reference_len'.\n" +
                "But be aware that not always a subsequent method is called -> Do NOT allocate memory here and try to release it in subsequent methods!\n\n" +
                "You also may replace function pointers in '{4}' param for get/test/set methods which contain the default values from table definition,\n" +
                "in order to provide special methods, for the currently processed cell. Changed pointers are only valid for current request.",
                getNextInstanceMethod.Parameter[1].Name,
                returnValue.Type.Name,
                LwipDefs.Def_ErrorCode_Ok,
                augmentsHint,
                getNextInstanceMethod.Parameter[2].Name
                )));

            getNextInstanceMethod.AddElement(new Comment(String.Format(
                "For easier processing and getting the next instance, you may use the 'snmp_next_oid_*' enumerator.\n" +
                "Simply pass all known instance OID's to it and it returns the next valid one:\n\n" +
                "{0} state;\n" +
                "{1} result_buf;\n" +
                "snmp_next_oid_init(&state, {2}->id, {2}->len, result_buf, LWIP_SNMP_OBJ_ID_LEN);\n" + 
                "while ({{not all instances passed}}) {{\n" + 
                "  {1} test_oid;\n" + 
                "  {{fill test_oid to create instance oid for next instance}}\n" + 
                "  snmp_next_oid_check(&state, test_oid->id, test_oid->len, {{target_data_ptr}});\n" + 
                "}}\n" + 
                "if(state.status == SNMP_NEXT_OID_STATUS_SUCCESS) {{\n" + 
                "  snmp_oid_assign(row_oid, result_buf->oid, result_buf->len);\n" +
                "  {3}->reference.ptr = state.reference; //==target_data_ptr, for usage in subsequent get/test/set\n" + 
                "  {4} = {5};\n" + 
                "}}"
                ,
                LwipDefs.Vt_StNextOidState,
                LwipDefs.Vt_StObjectId,
                getNextInstanceMethod.Parameter[1].Name,
                getNextInstanceMethod.Parameter[2].Name,
                returnValue.Type.Name,
                LwipDefs.Def_ErrorCode_Ok
                )));

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

    }
}