Move WPF code from SourceGenWPF to SourceGen

SourceGen/NavStack.cs

@@ -0,0 +1,173 @@
+/*
+ * Copyright 2019 faddenSoft
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Text;
+
+namespace SourceGen {
+    /// <summary>
+    /// Maintains a record of interesting places we've been.
+    /// </summary>
+    public class NavStack {
+        // It's tempting to use a single stack, and just move a cursor up and down.  However,
+        // that doesn't quite work.  We always want to record where you came from, so we're
+        // pushing locations on when moving both forward and backward.
+        //
+        // If you move backward and then jump somewhere else, we want to discard the list of
+        // previously-recorded forward places.
+        //
+        // Jumping to Notes is a little different from jumping to anything else, because we
+        // want to highlight the note rather than the code at the associated offset.  This
+        // is especially important when moving upward through the file, or the note will be
+        // off the top of the screen.
+
+        // TODO(someday): change the back button to a pop-up list of locations (like the way
+        //   VS 2017 does it).
+
+        /// <summary>
+        /// Holds enough information to get us back where we were, in style.
+        /// </summary>
+        public class Location {
+            public int Offset { get; set; }
+            public bool IsNote { get; set; }
+
+            public Location(int offset, bool isNote) {
+                Offset = offset;
+                IsNote = isNote;
+            }
+
+            public override string ToString() {
+                return string.Format("[+{0:x6},{1}]", Offset, IsNote);
+            }
+
+            public static bool operator ==(Location a, Location b) {
+                if (ReferenceEquals(a, b)) {
+                    return true;    // same object, or both null
+                }
+                if (ReferenceEquals(a, null) || ReferenceEquals(b, null)) {
+                    return false;   // one is null
+                }
+                return a.Offset == b.Offset && a.IsNote == b.IsNote;
+            }
+            public static bool operator !=(Location a, Location b) {
+                return !(a == b);
+            }
+            public override bool Equals(object obj) {
+                return obj is Location && this == (Location)obj;
+            }
+            public override int GetHashCode() {
+                return Offset + (IsNote ? (1<<24) : 0);
+            }
+        }
+
+        // Location stacks.
+        private List<Location> mBackStack = new List<Location>();
+        private List<Location> mFwdStack = new List<Location>();
+
+
+        public NavStack() { }
+
+        /// <summary>
+        /// True if there is an opportunity to pop backward.
+        /// </summary>
+        public bool HasBackward {
+            get {
+                return mBackStack.Count > 0;
+            }
+        }
+
+        /// <summary>
+        /// True if there is an opportunity to push forward.
+        /// </summary>
+        public bool HasForward {
+            get {
+                return mFwdStack.Count > 0;
+            }
+        }
+
+        /// <summary>
+        /// Clears the stacks.
+        /// </summary>
+        public void Clear() {
+            mBackStack.Clear();
+            mFwdStack.Clear();
+        }
+
+        /// <summary>
+        /// Pushes a new entry onto the back stack.  Clears the forward stack.
+        /// 
+        /// If the same entry is already at the top of the stack, the entry will not be added.
+        /// </summary>
+        /// <param name="curLoc">Current location.</param>
+        public void Push(Location curLoc) {
+            if (mBackStack.Count > 0 && mBackStack[mBackStack.Count - 1] == curLoc) {
+                Debug.WriteLine("Not re-pushing " + curLoc);
+                return;
+            }
+
+            mBackStack.Add(curLoc);
+            mFwdStack.Clear();
+
+            //Debug.WriteLine("Stack now: " + this);
+        }
+
+        /// <summary>
+        /// Pops the top element from the back stack, and pushes the current position
+        /// onto the forward stack.
+        /// </summary>
+        /// <param name="fromLoc">Current location.</param>
+        /// <returns>The location to move to.</returns>
+        public Location MoveBackward(Location fromLoc) {
+            if (mBackStack.Count == 0) {
+                throw new Exception("Stack is empty");
+            }
+            Location toLoc = mBackStack[mBackStack.Count - 1];
+            mBackStack.RemoveAt(mBackStack.Count - 1);
+            mFwdStack.Add(fromLoc);
+            return toLoc;
+        }
+
+        /// <summary>
+        /// Pops the top element from the forward stack, and pushes the current position
+        /// onto the back stack.
+        /// </summary>
+        /// <param name="fromLoc">Current location.</param>
+        /// <returns>The location to move to.</returns>
+        public Location MoveForward(Location fromLoc) {
+            if (mFwdStack.Count == 0) {
+                throw new Exception("Stack is empty");
+            }
+            Location toLoc = mFwdStack[mFwdStack.Count - 1];
+            mFwdStack.RemoveAt(mFwdStack.Count - 1);
+            mBackStack.Add(fromLoc);
+            return toLoc;
+        }
+
+        public override string ToString() {
+            StringBuilder sb = new StringBuilder();
+            sb.Append("Back:");
+            foreach (Location loc in mBackStack) {
+                sb.Append(loc);
+            }
+            sb.Append(" Fwd:");
+            foreach (Location loc in mFwdStack) {
+                sb.Append(loc);
+            }
+            return sb.ToString();
+        }
+    }
+}