New extension: Indentation based text objects

resources/META-INF/includes/VimExtensions.xml

@@ -101,6 +101,14 @@
         <alias name="Improved-paragraph-motion"/>
       </aliases>
     </vimExtension>
+
+    <vimExtension implementation="com.maddyhome.idea.vim.extension.textobjindent.VimIndentObject" name="textobj-indent">
+      <aliases>
+        <alias name="https://github.com/michaeljsmith/vim-indent-object"/>
+        <alias name="michaeljsmith/vim-indent-object"/>
+        <alias name="vim-indent-object"/>
+      </aliases>
+    </vimExtension>
   </extensions>
 
   <!--  IdeaVim extensions-->

src/com/maddyhome/idea/vim/extension/textobjindent/VimIndentObject.java

@@ -0,0 +1,292 @@
+/*
+ * IdeaVim - Vim emulator for IDEs based on the IntelliJ platform
+ * Copyright (C) 2003-2020 The IdeaVim authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.maddyhome.idea.vim.extension.textobjindent;
+
+import com.intellij.openapi.actionSystem.DataContext;
+import com.intellij.openapi.editor.Caret;
+import com.intellij.openapi.editor.Editor;
+import com.maddyhome.idea.vim.command.Argument;
+import com.maddyhome.idea.vim.command.Command;
+import com.maddyhome.idea.vim.command.CommandFlags;
+import com.maddyhome.idea.vim.command.CommandState;
+import com.maddyhome.idea.vim.command.MappingMode;
+import com.maddyhome.idea.vim.command.TextObjectVisualType;
+import com.maddyhome.idea.vim.common.TextRange;
+import com.maddyhome.idea.vim.extension.VimExtension;
+import com.maddyhome.idea.vim.extension.VimExtensionHandler;
+import com.maddyhome.idea.vim.handler.TextObjectActionHandler;
+import com.maddyhome.idea.vim.helper.InlayHelperKt;
+import com.maddyhome.idea.vim.listener.SelectionVimListenerSuppressor;
+import com.maddyhome.idea.vim.listener.VimListenerSuppressor;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.EnumSet;
+
+import static com.maddyhome.idea.vim.extension.VimExtensionFacade.putExtensionHandlerMapping;
+import static com.maddyhome.idea.vim.extension.VimExtensionFacade.putKeyMapping;
+import static com.maddyhome.idea.vim.group.visual.VisualGroupKt.vimSetSelection;
+import static com.maddyhome.idea.vim.helper.StringHelper.parseKeys;
+
+/**
+ * Port of vim-indent-object:
+ * https://github.com/michaeljsmith/vim-indent-object
+ *
+ * <p>
+ * vim-indent-object provides these text objects based on the cursor line's indentation:
+ * <ul>
+ *   <li><code>ai</code> <b>A</b>n <b>I</b>ndentation level and line above.</li>
+ *   <li><code>ii</code> <b>I</b>nner <b>I</b>ndentation level (no line above).</li>
+ *   <li><code>aI</code> <b>A</b>n <b>I</b>ndentation level and lines above and below.</li>
+ *   <li><code>iI</code> <b>I</b>nner <b>I</b>ndentation level (no lines above and below). Synonym of <code>ii</code></li>
+ * </ul>
+ *
+ * See also the reference manual for more details at:
+ * https://github.com/michaeljsmith/vim-indent-object/blob/master/doc/indent-object.txt
+ *
+ * @author Shrikant Kandula (@sharat87)
+ */
+public class VimIndentObject implements VimExtension {
+
+  @Override
+  public @NotNull
+  String getName() {
+    return "textobj-indent";
+  }
+
+  @Override
+  public void init() {
+    putExtensionHandlerMapping(MappingMode.XO, parseKeys("<Plug>textobj-indent-ai"), getOwner(),
+      new IndentObject(true, false), false);
+    putExtensionHandlerMapping(MappingMode.XO, parseKeys("<Plug>textobj-indent-aI"), getOwner(),
+      new IndentObject(true, true), false);
+    putExtensionHandlerMapping(MappingMode.XO, parseKeys("<Plug>textobj-indent-ii"), getOwner(),
+      new IndentObject(false, false), false);
+
+    putKeyMapping(MappingMode.XO, parseKeys("ai"), getOwner(), parseKeys("<Plug>textobj-indent-ai"), true);
+    putKeyMapping(MappingMode.XO, parseKeys("aI"), getOwner(), parseKeys("<Plug>textobj-indent-aI"), true);
+    putKeyMapping(MappingMode.XO, parseKeys("ii"), getOwner(), parseKeys("<Plug>textobj-indent-ii"), true);
+  }
+
+  static class IndentObject implements VimExtensionHandler {
+    final boolean includeAbove;
+    final boolean includeBelow;
+
+    IndentObject(boolean includeAbove, boolean includeBelow) {
+      this.includeAbove = includeAbove;
+      this.includeBelow = includeBelow;
+    }
+
+    static class IndentObjectHandler extends TextObjectActionHandler {
+      final boolean includeAbove;
+      final boolean includeBelow;
+
+      IndentObjectHandler(boolean includeAbove, boolean includeBelow) {
+        this.includeAbove = includeAbove;
+        this.includeBelow = includeBelow;
+      }
+
+      @Override
+      public @Nullable
+      TextRange getRange(@NotNull Editor editor, @NotNull Caret caret, @NotNull DataContext context,
+                         int count, int rawCount, @Nullable Argument argument) {
+        final CharSequence charSequence = editor.getDocument().getCharsSequence();
+        final int caretOffset = caret.getOffset();
+
+        // Part 1: Find the start of the caret line.
+        int caretLineStartOffset = caretOffset;
+        int accumulatedWhitespace = 0;
+        while (--caretLineStartOffset >= 0) {
+          final char ch = charSequence.charAt(caretLineStartOffset);
+          if (ch == ' ' || ch == '\t') {
+            ++accumulatedWhitespace;
+          } else if (ch == '\n') {
+            ++caretLineStartOffset;
+            break;
+          } else {
+            accumulatedWhitespace = 0;
+          }
+        }
+        if (caretLineStartOffset < 0) {
+          caretLineStartOffset = 0;
+        }
+
+        // `caretLineStartOffset` points to the first character in the line where the caret is located.
+
+        // Part 2: Compute the indentation level of the caret line.
+        // This is done as a separate step so that it works even when the caret is inside the indentation.
+        int offset = caretLineStartOffset;
+        int indentSize = 0;
+        while (++offset < charSequence.length()) {
+          final char ch = charSequence.charAt(offset);
+          if (ch == ' ' || ch == '\t') {
+            ++indentSize;
+          } else {
+            break;
+          }
+        }
+
+        // `indentSize` contains the amount of indent to be used for the text object range to be returned.
+
+        Integer upperBoundaryOffset = null;
+        // Part 3: Find a line above the caret line, that has an indentation lower than `indentSize`.
+        int pos1 = caretLineStartOffset - 1;
+        boolean isUpperBoundaryFound = false;
+        while (upperBoundaryOffset == null) {
+          // 3.1: Going backwards from `caretLineStartOffset`, find the first non-whitespace character.
+          while (--pos1 >= 0) {
+            final char ch = charSequence.charAt(pos1);
+            if (ch != ' ' && ch != '\t' && ch != '\n') {
+              break;
+            }
+          }
+          // 3.2: Find the indent size of the line with this non-whitespace character and check against `indentSize`.
+          accumulatedWhitespace = 0;
+          while (--pos1 >= 0) {
+            final char ch = charSequence.charAt(pos1);
+            if (ch == ' ' || ch == '\t') {
+              ++accumulatedWhitespace;
+            } else if (ch == '\n') {
+              if (accumulatedWhitespace < indentSize) {
+                upperBoundaryOffset = pos1 + 1;
+                isUpperBoundaryFound = true;
+              }
+              break;
+            } else {
+              accumulatedWhitespace = 0;
+            }
+          }
+          if (pos1 < 0) {
+            // Reached start of the buffer.
+            upperBoundaryOffset = 0;
+            isUpperBoundaryFound = accumulatedWhitespace < indentSize;
+          }
+        }
+
+        // Now `upperBoundaryOffset` marks the beginning of an `ai` text object.
+        if (isUpperBoundaryFound && !includeAbove) {
+          while (++upperBoundaryOffset < charSequence.length()) {
+            final char ch = charSequence.charAt(upperBoundaryOffset);
+            if (ch == '\n') {
+              ++upperBoundaryOffset;
+              break;
+            }
+          }
+          while (charSequence.charAt(upperBoundaryOffset) == '\n') {
+            ++upperBoundaryOffset;
+          }
+        }
+
+        // Part 4: Find the start of the caret line.
+        int caretLineEndOffset = caretOffset;
+        while (++caretLineEndOffset < charSequence.length()) {
+          final char ch = charSequence.charAt(caretLineEndOffset);
+          if (ch == '\n') {
+            ++caretLineEndOffset;
+            break;
+          }
+        }
+
+        // `caretLineEndOffset` points to the first charater in the line below caret line.
+
+        Integer lowerBoundaryOffset = null;
+        // Part 5: Find a line below the caret line, that has an indentation lower than `indentSize`.
+        int pos2 = caretLineEndOffset - 1;
+        boolean isLowerBoundaryFound = false;
+        while (lowerBoundaryOffset == null) {
+          int accumulatedWhitespace2 = 0;
+          int lastNewlinePos = caretLineEndOffset - 1;
+          boolean isInIndent = true;
+          while (++pos2 < charSequence.length()) {
+            final char ch = charSequence.charAt(pos2);
+            if (isIndentChar(ch) && isInIndent) {
+              ++accumulatedWhitespace2;
+            } else if (ch == '\n') {
+              accumulatedWhitespace2 = 0;
+              lastNewlinePos = pos2;
+              isInIndent = true;
+            } else {
+              if (isInIndent && accumulatedWhitespace2 < indentSize) {
+                lowerBoundaryOffset = lastNewlinePos;
+                isLowerBoundaryFound = true;
+                break;
+              }
+              isInIndent = false;
+            }
+          }
+          if (pos2 >= charSequence.length()) {
+            // Reached end of the buffer.
+            lowerBoundaryOffset = charSequence.length() - 1;
+          }
+        }
+
+        // Now `lowerBoundaryOffset` marks the end of an `ii` text object.
+        if (isLowerBoundaryFound && includeBelow) {
+          while (++lowerBoundaryOffset < charSequence.length()) {
+            final char ch = charSequence.charAt(lowerBoundaryOffset);
+            if (ch == '\n') {
+              break;
+            }
+          }
+        }
+
+        return new TextRange(upperBoundaryOffset, lowerBoundaryOffset);
+      }
+
+      @NotNull
+      @Override
+      public TextObjectVisualType getVisualType() {
+        return TextObjectVisualType.LINE_WISE;
+      }
+
+      private boolean isIndentChar(char ch) {
+        return ch == ' ' || ch == '\t';
+      }
+
+    }
+
+    @Override
+    public void execute(@NotNull Editor editor, @NotNull DataContext context) {
+      @NotNull CommandState commandState = CommandState.getInstance(editor);
+      int count = Math.max(1, commandState.getCommandBuilder().getCount());
+
+      final IndentObjectHandler textObjectHandler = new IndentObjectHandler(includeAbove, includeBelow);
+
+      if (!commandState.isOperatorPending()) {
+        editor.getCaretModel().runForEachCaret((Caret caret) -> {
+          final TextRange range = textObjectHandler.getRange(editor, caret, context, count, 0, null);
+          if (range != null) {
+            try (VimListenerSuppressor.Locked ignored = SelectionVimListenerSuppressor.INSTANCE.lock()) {
+              if (commandState.getMode() == CommandState.Mode.VISUAL) {
+                vimSetSelection(caret, range.getStartOffset(), range.getEndOffset() - 1, true);
+              } else {
+                InlayHelperKt.moveToInlayAwareOffset(caret, range.getStartOffset());
+              }
+            }
+          }
+
+        });
+      } else {
+        commandState.getCommandBuilder().completeCommandPart(new Argument(new Command(count,
+          textObjectHandler, Command.Type.MOTION,
+          EnumSet.noneOf(CommandFlags.class))));
+      }
+    }
+  }
+}