VIM-268 Completion for :e command

src/main/java/com/maddyhome/idea/vim/ui/ex/ExActions.kt

@@ -10,6 +10,9 @@ package com.maddyhome.idea.vim.ui.ex
 
 import com.intellij.openapi.diagnostic.logger
 import com.intellij.openapi.editor.textarea.TextComponentEditorImpl
+import com.intellij.openapi.fileEditor.FileEditorManager
+import com.intellij.openapi.vfs.VirtualFile
+import com.intellij.util.containers.CollectionFactory
 import com.maddyhome.idea.vim.KeyHandler
 import com.maddyhome.idea.vim.VimPlugin
 import com.maddyhome.idea.vim.api.LocalOptionInitialisationScenario
@@ -293,3 +296,65 @@ internal class ToggleInsertReplaceAction : TextAction(ExEditorKit.ToggleInsertRe
     private val logger = logger<ToggleInsertReplaceAction>()
   }
 }
+
+internal class AutocompleteAction: TextAction(ExEditorKit.Autocomplete){
+  override fun actionPerformed(e: ActionEvent) {
+    val currentEditor = ExEntryPanel.getInstance().entry.editor
+    val target = getTextComponent(e) as ExTextField
+    val text = target.actualText
+    // autocomplete for edit
+    if(text.startsWith("e ") || text.startsWith("edit ")){
+      // split after first space to get filename to autocomplete
+      val fileStart = text.substring(text.indexOf(' ', 0) + 1)
+      // find potential files
+      val project = currentEditor!!.project!!
+
+      // find all files in the folders that are open
+      val editors = FileEditorManager.getInstance(project).getAllEditors()
+      val names = CollectionFactory.createSmallMemoryFootprintSet<String>()
+      val parents = CollectionFactory.createSmallMemoryFootprintSet<VirtualFile>()
+      for(editor in editors){
+        val parent = editor.file.parent
+        // we need to check a parent file only one time
+        if(parent in parents){
+          continue
+        }
+        parents.add(parent)
+        val childrens = parent.children
+        if (childrens != null){
+          for(child in childrens){
+            if(!child.isDirectory()) {
+              val name = child.name
+              if (name.startsWith(fileStart)) {
+                names.add(name)
+              }
+            }
+          }
+        }
+      }
+
+      // have we found a match?
+      if(names.size > 0){
+        val first = names.first()
+        // find the common starting string
+        var common = ""
+        for((i,c) in first.withIndex()){
+          var allSame = true
+          for(name in names){
+            if(name[i] != c) {
+              allSame = false
+              break
+            }
+          }
+          if(allSame){
+            common += c
+          } else {
+            break
+          }
+        }
+        // append common starting string
+        target.text += common.substring(fileStart.length)
+      }
+    }
+  }
+}

src/main/java/com/maddyhome/idea/vim/ui/ex/ExEditorKit.kt

@@ -59,6 +59,9 @@ internal object ExEditorKit : DefaultEditorKit() {
   @NonNls
   val StartLiteral: String = "start-literal"
 
+  @NonNls
+  val Autocomplete: String = "autocomplete"
+
   private val logger = logger<ExEditorKit>()
 
   /**
@@ -109,6 +112,7 @@ internal object ExEditorKit : DefaultEditorKit() {
     HistoryDownFilterAction(),
     ToggleInsertReplaceAction(),
     InsertRegisterAction(),
+    AutocompleteAction(),
   )
 
   class DefaultExKeyHandler : DefaultKeyTypedAction() {

src/main/java/com/maddyhome/idea/vim/ui/ex/ExKeyBindings.kt

@@ -73,6 +73,8 @@ internal object ExKeyBindings {
 
       KeyBinding(KeyStroke.getKeyStroke(KeyEvent.VK_R, KeyEvent.CTRL_DOWN_MASK), ExEditorKit.InsertRegister),
 
+      KeyBinding(KeyStroke.getKeyStroke(KeyEvent.VK_TAB, 0), ExEditorKit.Autocomplete),
+
       // These appear to be non-Vim shortcuts
       KeyBinding(KeyStroke.getKeyStroke(KeyEvent.VK_V, KeyEvent.META_DOWN_MASK), DefaultEditorKit.pasteAction),
       KeyBinding(KeyStroke.getKeyStroke(KeyEvent.VK_INSERT, KeyEvent.SHIFT_DOWN_MASK), DefaultEditorKit.pasteAction),

src/test/java/org/jetbrains/plugins/ideavim/ui/ShowCmdTest.kt

@@ -10,6 +10,7 @@ package org.jetbrains.plugins.ideavim.ui
 
 import com.maddyhome.idea.vim.api.injector
 import com.maddyhome.idea.vim.ui.ShowCmd
+import com.maddyhome.idea.vim.ui.ex.ExEntryPanel
 import org.jetbrains.plugins.ideavim.SkipNeovimReason
 import org.jetbrains.plugins.ideavim.TestWithoutNeovim
 import org.jetbrains.plugins.ideavim.VimBehaviorDiffers
@@ -244,7 +245,29 @@ class ShowCmdTest : VimTestCase() {
     assertEquals("22\"a22\"a22\"a22\"a22d22", getShowCmdTooltipText())
   }
 
+  @TestWithoutNeovim(reason = SkipNeovimReason.SHOW_CMD)
+  @Test
+  fun `test edit autocomplete`() {
+    // the test document is called aaa.txt, so we can use it to autocomplete to that filename
+    typeText(injector.parser.parseKeys(":edit aa\t"))
+
+    // check if the text of the panel got autocompleted
+    assertEquals("edit aaa.txt", getExEntryPanelText())
+  }
+
+  @TestWithoutNeovim(reason = SkipNeovimReason.SHOW_CMD)
+  @Test
+  fun `test e autocomplete`() {
+    // the test document is called aaa.txt, so we can use it to autocomplete to that filename
+    typeText(injector.parser.parseKeys(":e aa\t"))
+
+    // check if the text of the panel got autocompleted
+    assertEquals("e aaa.txt", getExEntryPanelText())
+  }
+
   private fun getShowCmdText() = ShowCmd.getWidgetText(fixture.editor!!)
 
   private fun getShowCmdTooltipText() = ShowCmd.getFullText(fixture.editor!!)
+
+  private fun getExEntryPanelText() = ExEntryPanel.getInstance().text
 }