PY-84031: Move GoWelcomeScreenCommandLineProjectOpenProcessor to platform

Space-RevId: 187463a2b4d426d9a0dd30dcd85e438122347a9c

GitOrigin-RevId: 1096099045f7fbe27f5125b3f98a3c3b346f3ced

platform/non-modal-welcome-screen/resources/intellij.platform.ide.nonModalWelcomeScreen.xml

@@ -25,6 +25,8 @@
 
     <noProjectStateHandler implementation="com.intellij.platform.ide.nonModalWelcomeScreen.WelcomeScreenNoProjectStateHandler" order="first"/>
 
+    <projectOpenProcessor implementation="com.intellij.platform.ide.nonModalWelcomeScreen.WelcomeScreenCommandLineProjectOpenProcessor" order="first"/>
+
     <actionConfigurationCustomizer implementation="com.intellij.platform.ide.nonModalWelcomeScreen.actions.WelcomeScreenAwareActionsCustomizer" />
 
     <fileEditorProvider id="settingsWindow" implementation="com.intellij.platform.ide.nonModalWelcomeScreen.rightTab.WelcomeScreenRightTabVirtualFileEditorProvider"/>

platform/non-modal-welcome-screen/src/com/intellij/platform/ide/nonModalWelcomeScreen/WelcomeScreenCommandLineProjectOpenProcessor.kt

@@ -0,0 +1,65 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.platform.ide.nonModalWelcomeScreen
+
+import com.intellij.ide.impl.OpenProjectTask
+import com.intellij.ide.projectView.ProjectView
+import com.intellij.openapi.application.EDT
+import com.intellij.openapi.components.serviceAsync
+import com.intellij.openapi.fileEditor.FileEditorManager
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.vfs.LocalFileSystem
+import com.intellij.openapi.vfs.VirtualFile
+import com.intellij.openapi.wm.ex.executeNoProjectStateHandlerExpectingNonWelcomeScreenImplementation
+import com.intellij.openapi.wm.ex.getWelcomeScreenProjectProvider
+import com.intellij.platform.CommandLineProjectOpenProcessor
+import com.intellij.platform.ide.diagnostic.startUpPerformanceReporter.FUSProjectHotStartUpMeasurer
+import com.intellij.platform.ide.nonModalWelcomeScreen.rightTab.WelcomeScreenPreventWelcomeTabFocusService
+import com.intellij.projectImport.ProjectOpenProcessor
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.nio.file.Path
+
+/**
+ * A dummy implementation of ProjectOpenProcessor that serves as a bridge for CommandLineProjectOpenProcessor.
+ *
+ * This class exists because the platform code searches for CommandLineProjectOpenProcessor implementations
+ * among ProjectOpenProcessor extensions (see CommandLineProjectOpenProcessor.getInstanceIfExists()).
+ * Although these are conceptually independent interfaces, CommandLineProjectOpenProcessor must be registered
+ * as a ProjectOpenProcessor extension point to be discoverable by the platform.
+ *
+ * The actual functionality is provided through the CommandLineProjectOpenProcessor interface methods.
+ */
+private abstract class DummyProjectOpenProcessor(override val name: String) : ProjectOpenProcessor(), CommandLineProjectOpenProcessor {
+  override fun canOpenProject(file: VirtualFile): Boolean = false
+
+  /**
+   * Throws UnsupportedOperationException as this method should never be called.
+   * The contract is established by canOpenProject() always returning false.
+   * @see canOpenProject
+   */
+  override suspend fun openProjectAsync(virtualFile: VirtualFile, projectToClose: Project?, forceOpenInNewFrame: Boolean): Project? =
+    throw UnsupportedOperationException()
+}
+
+private class WelcomeScreenCommandLineProjectOpenProcessor : DummyProjectOpenProcessor("WelcomeScreenCommandLineProjectOpenProcessor") {
+  override suspend fun openProjectAndFile(file: Path, tempProject: Boolean, options: OpenProjectTask): Project? {
+    val provider = getWelcomeScreenProjectProvider() ?: return null
+    return openWelcomeScreenProject(file)
+  }
+
+  private suspend fun openWelcomeScreenProject(file: Path): Project {
+    FUSProjectHotStartUpMeasurer.lightEditProjectFound()
+    val project = executeNoProjectStateHandlerExpectingNonWelcomeScreenImplementation()
+    project.serviceAsync<WelcomeScreenPreventWelcomeTabFocusService>().preventFocusOnWelcomeTab()
+    LocalFileSystem.getInstance().refreshAndFindFileByNioFile(file)?.let { focusOnFile(project, it) }
+    return project
+  }
+
+  private suspend fun focusOnFile(project: Project, virtualFile: VirtualFile) {
+    val fileEditorManager = project.serviceAsync<FileEditorManager>()
+    withContext(Dispatchers.EDT) {
+      fileEditorManager.openFile(virtualFile, true)
+      ProjectView.getInstance(project).select(null, virtualFile, true)
+    }
+  }
+}