PowerShell · Dongbo Wang (daxian-dbw) · Dec 20, 2018 · Dec 14, 2018 · Dec 18, 2018 · Dec 18, 2018
@@ -758,6 +758,12 @@ public SwitchParameter AutoSize
         }
         private Nullable<bool> _autosize = null;
 
+        /// <summary>
+        /// Gets or sets if header is repeated per screen.
+        /// </summary>
+        [Parameter]
+        public SwitchParameter RepeatHeader { get; set; }
+
         /// <summary>
         /// optional, non positional parameter
         /// </summary>
@@ -809,6 +815,11 @@ internal override FormattingCommandLineParameters GetCommandLineParameters()
             if (_autosize.HasValue)
                 parameters.autosize = _autosize.Value;
 
+            if (RepeatHeader)
+            {
+                parameters.repeatHeader = true;
+            }
+
             parameters.groupByParameter = this.ProcessGroupByParameter();
 
             TableSpecificParameters tableParameters = new TableSpecificParameters();

@@ -45,6 +45,12 @@ internal sealed class FormattingCommandLineParameters
         /// </summary>
         internal Nullable<bool> autosize = null;
 
+        /// <summary>
+        /// If true, the header for a table is repeated after each screen full
+        /// of content.
+        /// </summary>
+        internal bool repeatHeader = false;
+
         /// <summary>
         /// errors are shown as out of band messages
         /// </summary>

@@ -250,6 +250,7 @@ private enum FormattingState
         private enum PreprocessingState { raw, processed, error }
 
         private const int DefaultConsoleWidth = 120;
+        private const int DefaultConsoleHeight = int.MaxValue;
         internal const int StackAllocThreshold = 120;
 
         /// <summary>
@@ -743,20 +744,14 @@ private void ProcessCachedGroupOnWide(WideViewHeaderInfo wvhi, List<PacketInfoDa
             _formattingHint = hint;
         }
 
-        /// <summary>
-        /// In cases like implicit remoting, there is no console so reading the console width results in an exception.
-        /// Instead of handling exception every time we cache this value to increase performance.
-        /// </summary>
-        static private bool _noConsole = false;
-
         /// <summary>
         /// Tables and Wides need to use spaces for padding to maintain table look even if console window is resized.
         /// For all other output, we use int.MaxValue if the user didn't explicitly specify a width.
         /// If we detect that int.MaxValue is used, first we try to get the current console window width.
         /// However, if we can't read that (for example, implicit remoting has no console window), we default
         /// to something reasonable: 120 columns.
         /// </summary>
-        static private int GetConsoleWindowWidth(int columnNumber)
+        private static int GetConsoleWindowWidth(int columnNumber)
         {
             if (InternalTestHooks.SetConsoleWidthToZero)
             {
@@ -765,10 +760,6 @@ static private int GetConsoleWindowWidth(int columnNumber)
 
             if (columnNumber == int.MaxValue)
             {
-                if (_noConsole)
-                {
-                    return DefaultConsoleWidth;
-                }
                 try
                 {
                     // if Console width is set to 0, the default width is returned so that the output string is not null.
@@ -777,13 +768,40 @@ static private int GetConsoleWindowWidth(int columnNumber)
                 }
                 catch
                 {
-                    _noConsole = true;
                     return DefaultConsoleWidth;
                 }
             }
+
             return columnNumber;
         }
 
+        /// <summary>
+        /// Return the console height.null  If not available (like when remoting), treat as Int.MaxValue.
+        /// </summary>
+        private static int GetConsoleWindowHeight(int rowNumber)
+        {
+            if (InternalTestHooks.SetConsoleHeightToZero)
+            {
+                return DefaultConsoleHeight;
+            }
+
+            if (rowNumber <= 0)
+            {
+                try
+                {
+                    // if Console height is set to 0, the default height is returned.
+                    // This can happen in environments where TERM is not set.
+                    return (Console.WindowHeight > 0) ? Console.WindowHeight : DefaultConsoleHeight;
+                }
+                catch
+                {
+                    return DefaultConsoleHeight;
+                }
+            }
+
+            return rowNumber;
+        }
+
         /// <summary>
         /// base class for all the formatting hints
         /// </summary>
@@ -925,6 +943,12 @@ internal TableOutputContextBase(OutCommandInner cmd,
 
         private sealed class TableOutputContext : TableOutputContextBase
         {
+            private int _rowCount = 0;
+            private int _consoleHeight = -1;
+            private int _consoleWidth = -1;
+            private const int WhitespaceAndPagerLineCount = 2;
+            private bool _repeatHeader = false;
+
             /// <summary>
             /// construct a context to push on the stack
             /// </summary>
@@ -936,6 +960,13 @@ internal TableOutputContext(OutCommandInner cmd,
                 GroupStartData formatData)
                 : base(cmd, parentContext, formatData)
             {
+                if (parentContext is FormatOutputContext foc)
+                {
+                    if (foc.Data.shapeInfo is TableHeaderInfo thi)
+                    {
+                        _repeatHeader = thi.repeatHeader;
+                    }
+                }
             }
 
             /// <summary>
@@ -952,7 +983,8 @@ internal override void Initialize()
                     columnWidthsHint = tableHint.columnWidths;
                 }
 
-                int columnsOnTheScreen = GetConsoleWindowWidth(this.InnerCommand._lo.ColumnNumber);
+                _consoleHeight = GetConsoleWindowHeight(this.InnerCommand._lo.RowNumber);
+                _consoleWidth = GetConsoleWindowWidth(this.InnerCommand._lo.ColumnNumber);
 
                 int columns = this.CurrentTableHeaderInfo.tableColumnInfoList.Count;
                 if (columns == 0)
@@ -971,7 +1003,7 @@ internal override void Initialize()
                     alignment[k] = tci.alignment;
                     k++;
                 }
-                this.Writer.Initialize(0, columnsOnTheScreen, columnWidths, alignment, this.CurrentTableHeaderInfo.hideHeader);
+                this.Writer.Initialize(0, _consoleWidth, columnWidths, alignment, this.CurrentTableHeaderInfo.hideHeader);
             }
 
             /// <summary>
@@ -992,7 +1024,7 @@ internal override void GroupStart()
                 {
                     properties[k++] = tci.label ?? tci.propertyName;
                 }
-                this.Writer.GenerateHeader(properties, this.InnerCommand._lo);
+                _rowCount += this.Writer.GenerateHeader(properties, this.InnerCommand._lo);
             }
 
             /// <summary>
@@ -1008,6 +1040,12 @@ internal override void ProcessPayload(FormatEntryData fed)
                     return;
                 }
 
+                if (_repeatHeader && _rowCount >= _consoleHeight - WhitespaceAndPagerLineCount)
+                {
+                    this.InnerCommand._lo.WriteLine(string.Empty);
+                    _rowCount = this.Writer.GenerateHeader(null, this.InnerCommand._lo);
+                }
+
                 TableRowEntry tre = fed.formatEntryInfo as TableRowEntry;
 
                 // need to make sure we have matching counts: the header count will have to prevail
@@ -1029,7 +1067,8 @@ internal override void ProcessPayload(FormatEntryData fed)
                         alignment[k] = TextAlignment.Left; // hard coded default
                     }
                 }
-                this.Writer.GenerateRow(values, this.InnerCommand._lo, tre.multiLine, alignment, InnerCommand._lo.DisplayCells);
+                this.Writer.GenerateRow(values, this.InnerCommand._lo, tre.multiLine, alignment, InnerCommand._lo.DisplayCells, generatedRows: null);
+                _rowCount++;
             }
 
             private TableHeaderInfo CurrentTableHeaderInfo
@@ -1182,7 +1221,7 @@ internal override void Initialize()
                     alignment[k] = TextAlignment.Left;
                 }
 
-                this.Writer.Initialize(0, columnsOnTheScreen, columnWidths, alignment, false);
+                this.Writer.Initialize(0, columnsOnTheScreen, columnWidths, alignment, false, GetConsoleWindowHeight(this.InnerCommand._lo.RowNumber));
             }
 
             /// <summary>
@@ -1239,7 +1278,7 @@ private void WriteStringBuffer()
                     else
                         values[k] = string.Empty;
                 }
-                this.Writer.GenerateRow(values, this.InnerCommand._lo, false, null, InnerCommand._lo.DisplayCells);
+                this.Writer.GenerateRow(values, this.InnerCommand._lo, false, null, InnerCommand._lo.DisplayCells, generatedRows: null);
                 _buffer.Reset();
             }
 

@@ -424,6 +424,11 @@ internal abstract class ControlBody : ControlBase
         /// RULE: valid only for table and wide only
         /// </summary>
         internal bool? autosize = null;
+
+        /// <summary>
+        /// RULE: only valid for table
+        /// </summary>
+        internal bool repeatHeader = false;
     }
 
     /// <summary>

@@ -63,6 +63,7 @@ private void InitializeHelper()
             InitializeFormatErrorManager();
             InitializeGroupBy();
             InitializeAutoSize();
+            InitializeRepeatHeader();
         }
 
         private void InitializeFormatErrorManager()
@@ -147,6 +148,14 @@ private void InitializeAutoSize()
             }
         }
 
+        private void InitializeRepeatHeader()
+        {
+            if (parameters != null)
+            {
+                _repeatHeader = parameters.repeatHeader;
+            }
+        }
+
         internal virtual FormatStartData GenerateStartData(PSObject so)
         {
             FormatStartData startFormat = new FormatStartData();
@@ -312,6 +321,12 @@ protected bool AutoSize
         }
         private bool _autosize = false;
 
+        protected bool RepeatHeader
+        {
+            get { return _repeatHeader; }
+        }
+        private bool _repeatHeader = false;
+
         protected class DataBaseInfo
         {
             internal TypeInfoDataBase db = null;

@@ -156,6 +156,7 @@ private TableHeaderInfo GenerateTableHeaderInfoFromDataBaseInfo(PSObject so)
             bool dummy;
             List<TableRowItemDefinition> activeRowItemDefinitionList = GetActiveTableRowDefinition(_tableBody, so, out dummy);
             thi.hideHeader = this.HideHeaders;
+            thi.repeatHeader = this.RepeatHeader;
 
             int col = 0;
             foreach (TableRowItemDefinition rowItem in activeRowItemDefinitionList)
@@ -293,6 +294,19 @@ private bool HideHeaders
             }
         }
 
+        private bool RepeatHeaders
+        {
+            get
+            {
+                if (this.parameters != null)
+                {
+                    return this.parameters.repeatHeader;
+                }
+
+                return false;
+            }
+        }
+
         private static int ComputeDefaultAlignment(PSObject so, PSPropertyExpression ex)
         {
             List<PSPropertyExpressionResult> rList = ex.GetValues(so);

@@ -220,6 +220,7 @@ public TableHeaderInfo()
         public override string ClassId2e4f51ef21dd47e99d3c952918aff9cd { get { return CLSID; } }
 
         public bool hideHeader;
+        public bool repeatHeader;
         public List<TableColumnInfo> tableColumnInfoList;
     }
 

@@ -575,6 +575,7 @@ internal override void Deserialize(PSObject so, FormatObjectDeserializer deseria
         {
             base.Deserialize(so, deserializer);
             this.hideHeader = deserializer.DeserializeBoolMemberVariable(so, "hideHeader");
+            this.hideHeader = deserializer.DeserializeBoolMemberVariable(so, "repeatHeader");
             FormatInfoDataListDeserializer<TableColumnInfo>.ReadList(so, "tableColumnInfoList", this.tableColumnInfoList, deserializer);
         }
     }