MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4using System.Collections.Generic;5 6namespace Microsoft.PowerShell.Commands.Internal.Format7{8    /// <summary>9    /// INTERNAL IMPLEMENTATION CLASS10    ///11    /// It manages the finite state machine for the sequence of formatting messages.12    /// It achieves this by maintaining a stack of OutputContext-derived objects.13    /// A predefined set of events allows the host of this class to process the information14    /// as it comes trough the finite state machine (push model)15    ///16    /// IMPORTANT: The code using this class will have to provide ALL the callbacks.17    /// </summary>18    internal class FormatMessagesContextManager19    {20        // callbacks declarations21        internal delegate OutputContext FormatContextCreationCallback(OutputContext parentContext, FormatInfoData formatData);22 23        internal delegate void FormatStartCallback(OutputContext c);24 25        internal delegate void FormatEndCallback(FormatEndData fe, OutputContext c);26 27        internal delegate void GroupStartCallback(OutputContext c);28 29        internal delegate void GroupEndCallback(GroupEndData fe, OutputContext c);30 31        internal delegate void PayloadCallback(FormatEntryData formatEntryData, OutputContext c);32 33        // callback instances34        internal FormatContextCreationCallback contextCreation = null;35        internal FormatStartCallback fs = null;36        internal FormatEndCallback fe = null;37        internal GroupStartCallback gs = null;38        internal GroupEndCallback ge = null;39        internal PayloadCallback payload = null;40 41        /// <summary>42        /// The current output context, as determined by the43        /// sequence of formatting messages in the object stream.44        /// </summary>45        internal abstract class OutputContext46        {47            /// <summary>48            /// </summary>49            /// <param name="parentContextInStack">Parent context in the stack, it can be null.</param>50            internal OutputContext(OutputContext parentContextInStack)51            {52                ParentContext = parentContextInStack;53            }54 55            /// <summary>56            /// The outer context: the context object pushed onto the57            /// stack before the current one. For the first object pushed onto58            /// the stack it will be null.59            /// </summary>60            internal OutputContext ParentContext { get; }61        }62 63        /// <summary>64        /// Process an object from an input stream. It manages the context stack and65        /// calls back on the specified event delegates.66        /// </summary>67        /// <param name="o">Object to process.</param>68        internal void Process(object o)69        {70            PacketInfoData formatData = o as PacketInfoData;71            if (formatData is FormatEntryData fed)72            {73                OutputContext ctx = null;74 75                if (!fed.outOfBand)76                {77                    ctx = _stack.Peek();78                }79                //  notify for Payload80                this.payload(fed, ctx);81            }82            else83            {84                bool formatDataIsFormatStartData = formatData is FormatStartData;85                bool formatDataIsGroupStartData = formatData is GroupStartData;86                // it's one of our formatting messages87                // we assume for the moment that they are in the correct sequence88                if (formatDataIsFormatStartData || formatDataIsGroupStartData)89                {90                    OutputContext oc = this.contextCreation(this.ActiveOutputContext, formatData);91                    _stack.Push(oc);92 93                    // now we have the context properly set: need to notify the94                    // underlying algorithm to do the start document or group stuff95                    if (formatDataIsFormatStartData)96                    {97                        // notify for Fs98                        this.fs(oc);99                    }100                    else if (formatDataIsGroupStartData)101                    {102                        // GroupStartData gsd = (GroupStartData) formatData;103                        // notify for Gs104                        this.gs(oc);105                    }106                }107                else108                {109                    GroupEndData ged = formatData as GroupEndData;110                    FormatEndData fEndd = formatData as FormatEndData;111                    if (ged != null || fEndd != null)112                    {113                        OutputContext oc = _stack.Peek();114                        if (fEndd != null)115                        {116                            // notify for Fe, passing the Fe info, before a Pop()117                            this.fe(fEndd, oc);118                        }119                        else if (ged != null)120                        {121                            // notify for Fe, passing the Fe info, before a Pop()122                            this.ge(ged, oc);123                        }124 125                        _stack.Pop();126                    }127                }128            }129        }130 131        /// <summary>132        /// Access the active context (top of the stack). It can be null.133        /// </summary>134        internal OutputContext ActiveOutputContext135        {136            get { return (_stack.Count > 0) ? _stack.Peek() : null; }137        }138 139        /// <summary>140        /// Internal stack to manage context.141        /// </summary>142        private readonly Stack<OutputContext> _stack = new Stack<OutputContext>();143    }144}145