QueryTreeBuilder.cs source code in C# .NET

                        Code:
                         / WCF / WCF / 3.5.30729.1 / untmp / Orcas / SP / ndp / cdf / src / WCF / ServiceModel / System / ServiceModel / Dispatcher / QueryTreeBuilder.cs / 1 / QueryTreeBuilder.cs
                        
                        
                            //------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------
namespace System.ServiceModel.Dispatcher
{ 
    using System.Diagnostics;
 
    internal class QueryTreeBuilder 
    {
        Diverger diverger; 
        Opcode lastOpcode;

        internal QueryTreeBuilder()
        { 
        }
 
        internal Opcode LastOpcode 
        {
            get 
            {
                return this.lastOpcode;
            }
        } 

        internal Opcode Build(Opcode tree, OpcodeBlock newBlock) 
        { 
            if (null == tree)
            { 
                this.lastOpcode = newBlock.Last;
                return newBlock.First;
            }
 
            this.diverger = new Diverger(tree, newBlock.First);
 
            if (!this.diverger.Find()) 
            {
                // The opcodes in newBlock already have equivalents or identical opcodes 
                // in the query tree that can do the job
                DiagnosticUtility.DebugAssert(this.diverger.TreePath.Count > 0, "");
                this.lastOpcode = this.diverger.TreePath[this.diverger.TreePath.Count - 1];
                return tree; 
            }
 
            DiagnosticUtility.DebugAssert(this.diverger.TreePath.Count == this.diverger.InsertPath.Count, ""); 

            // We can reuse opcodes upto this.diverger.TreePath[this.diverger.TreePath.Count - 1] 
            // The remainder of the code in newBlock must be executed as is...
            if (null == this.diverger.TreeOpcode)
            {
                // We reached a leaf in the query tree 
                // Simply add the remainder of the inserted code to the end of the tree path..
                this.diverger.TreePath[this.diverger.TreePath.Count - 1].Attach(this.diverger.InsertOpcode); 
            } 
            else
            { 
                // Merge in the remaider of the new code block into the query tree
                // The first diverging opcodes follow the last entry in each path
                this.diverger.TreeOpcode.Add(this.diverger.InsertOpcode);
            } 

            this.lastOpcode = newBlock.Last; 
            if (OpcodeID.MatchMultipleFilterResult == this.diverger.InsertOpcode.ID) 
            {
                // The complete new block was merged in, except for the the actual result opcode, which never 
                // automatically merges. This means that the new block found all of its opcodes in common with
                // the tree
                if (OpcodeID.Branch == this.diverger.TreeOpcode.ID)
                { 
                    OpcodeList branches = (((BranchOpcode) this.diverger.TreeOpcode).Branches);
                    for (int i = 0, count = branches.Count; i < count; ++i) 
                    { 
                        if (OpcodeID.MatchMultipleFilterResult == branches[i].ID)
                        { 
                            this.lastOpcode = branches[i];
                            break;
                        }
                    } 
                }
                else if (OpcodeID.MatchMultipleFilterResult == this.diverger.TreeOpcode.ID) 
                { 
                    this.lastOpcode = this.diverger.TreeOpcode;
                } 
            }

            // Since we'll be diverging, any jumps that preceeded and leapt past the divergence point
            // will have to be branched 
            this.FixupJumps();
 
            return tree; 
        }
 
        void FixupJumps()
        {
            QueryBuffer treePath = this.diverger.TreePath;
            QueryBuffer insertPath = this.diverger.InsertPath; 

            for (int i = 0; i < insertPath.Count; ++i) 
            { 
                if (insertPath[i].TestFlag(OpcodeFlags.Jump))
                { 
                    DiagnosticUtility.DebugAssert(treePath[i].ID == insertPath[i].ID, "");
                    JumpOpcode insertJump = (JumpOpcode) insertPath[i];
                    // Opcodes in 'insertPath' have equivalent opcodes in the query tree: i.e. the query tree contains an
                    // an equivalent execution path (upto the point of divergence naturally) that will produce in an identical 
                    // result. The remainder of the query tree (anything that lies beyond the point of divergence) represents
                    // a distinct execution path and is grafted onto the tree as a new branch. In fact, we simply break off 
                    // the remainder from the query being inserted and graft it onto the query tree. 
                    // If there are jumps on the insert path that jump to opcodes NOT in the insert path, then the jumps
                    // will reach opcodes in the new branch we will add(see above). However, because the actual jump opcodes 
                    // are shared (used as is from the query tree), the actual jump must also be branched. One jump will
                    // continue to jump to the original opcode and the second new one will jump to an opcode in the grafted branch.
                    if (-1 == insertPath.IndexOf(insertJump.Jump, i + 1))
                    { 
                        DiagnosticUtility.DebugAssert(insertJump.Jump.ID == OpcodeID.BlockEnd, "");
 
                        BlockEndOpcode jumpTo = (BlockEndOpcode) insertJump.Jump; 
                        // no longer jumping from insertJump to jumpTo
                        insertJump.RemoveJump(jumpTo); 

                        // Instead, jumping from treePath[i] to jumpTo
                        JumpOpcode treeJump = (JumpOpcode) treePath[i];
                        treeJump.AddJump(jumpTo); 
                    }
                } 
            } 
        }
 
        // Can handle queries being merged into trees but not trees merged into trees.
        // In other words, no branch opcodes in the query being inserted
        internal struct Diverger
        { 
            Opcode treeOpcode;
            QueryBuffer treePath; 
            QueryBuffer insertPath; 
            Opcode insertOpcode;
 
            internal Diverger(Opcode tree, Opcode insert)
            {
                this.treePath = new QueryBuffer(16);
                this.insertPath = new QueryBuffer(16); 
                this.treeOpcode = tree;
                this.insertOpcode = insert; 
            } 

            internal Opcode InsertOpcode 
            {
                get
                {
                    return this.insertOpcode; 
                }
            } 
 
            internal QueryBuffer InsertPath
            { 
                get
                {
                    return this.insertPath;
                } 
            }
 
            internal Opcode TreeOpcode 
            {
                get 
                {
                    return this.treeOpcode;
                }
            } 

            internal QueryBuffer TreePath 
            { 
                get
                { 
                    return this.treePath;
                }
            }
 
            // Stops at the last common node on each
            internal bool Find() 
            { 
                Opcode treeNext = null;
                while (true) 
                {
                    if (null == this.treeOpcode && null == this.insertOpcode)
                    {
                        return false; // no diverge. both ran out at the same time 
                    }
                    if (null == this.insertOpcode) 
                    { 
                        return false; // Ran out before tree did. No divergence.
                    } 
                    if (null == this.treeOpcode)
                    {
                        return true; // tree ran out before insert. Divergence
                    } 
                    if (this.treeOpcode.TestFlag(OpcodeFlags.Branch))
                    { 
                        treeNext = this.treeOpcode.Locate(this.insertOpcode); 
                        if (null == treeNext)
                        { 
                            return true; // divergence
                        }
                        this.treeOpcode = treeNext;
                        treeNext = treeNext.Next; 
                    }
                    else 
                    { 
                        if (!this.treeOpcode.Equals(this.insertOpcode))
                        { 
                            return true; // divergence, obviously
                        }
                        treeNext = this.treeOpcode.Next;
                    } 
                    // No divergence. Add to paths
                    this.treePath.Add(this.treeOpcode); 
                    this.insertPath.Add(this.insertOpcode); 
                    this.insertOpcode = this.insertOpcode.Next;
                    this.treeOpcode = treeNext; 
                }
            }
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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QueryTreeBuilder.cs source code in C# .NET

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