FIR IDE: introduce base class for completion provider

idea/idea-fir/src/org/jetbrains/kotlin/idea/completion/KotlinFirCompletionContributor.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.idea.completion.context.FirBasicCompletionContext
 import org.jetbrains.kotlin.idea.completion.context.FirNameReferencePositionContext
 import org.jetbrains.kotlin.idea.completion.context.FirPositionCompletionContextDetector
 import org.jetbrains.kotlin.idea.completion.context.FirUnknownPositionContext
+import org.jetbrains.kotlin.idea.completion.contributors.FirCompletionContributorBase
 import org.jetbrains.kotlin.idea.completion.weighers.Weighers
 import org.jetbrains.kotlin.idea.fir.low.level.api.IndexHelper
 import org.jetbrains.kotlin.idea.fir.low.level.api.util.originalKtFile
@@ -48,7 +49,7 @@ private object KotlinFirCompletionProvider : CompletionProvider<CompletionParame
             parameters.position.getModuleInfo().contentScope()
         )
 
-        val basicContext = FirBasicCompletionContext.createFromParameters(parameters, result) ?: return
+        val basicContext = FirBasicCompletionContext.createFromParameters(parameters, resultSet) ?: return
         recordOriginalFile(basicContext)
         val positionContext = FirPositionCompletionContextDetector.detect(basicContext)
 
@@ -65,9 +66,9 @@ private object KotlinFirCompletionProvider : CompletionProvider<CompletionParame
         FirPositionCompletionContextDetector.analyseInContext(basicContext, positionContext) {
             when (positionContext) {
                 is FirNameReferencePositionContext -> with(
-                    KotlinWithNameReferenceCompletionProvider(resultSet.prefixMatcher, indexHelper)
+                    KotlinWithNameReferenceCompletionProvider(basicContext, indexHelper)
                 ) {
-                    addCompletions(basicContext, positionContext)
+                    addCompletions(positionContext)
                 }
                 is FirUnknownPositionContext -> {
                     // TODO
@@ -135,9 +136,9 @@ internal fun interface CompletionVisibilityChecker {
  * TODO refactor it, try to split into several classes, or decompose it into several classes.
  */
 private class KotlinWithNameReferenceCompletionProvider(
-    private val prefixMatcher: PrefixMatcher,
+    basicContext: FirBasicCompletionContext,
     private val indexHelper: IndexHelper
-) {
+): FirCompletionContributorBase(basicContext) {
     private val lookupElementFactory = KotlinFirLookupElementFactory()
     private val typeNamesProvider = TypeNamesProvider(indexHelper)
 
@@ -165,20 +166,19 @@ private class KotlinWithNameReferenceCompletionProvider(
     }
 
     fun KtAnalysisSession.addCompletions(
-        basicContext: FirBasicCompletionContext,
         positionContext: FirNameReferencePositionContext
     ) = with(positionContext) {
-        val fileSymbol = basicContext.originalKtFile.getFileSymbol()
+        val fileSymbol = originalKtFile.getFileSymbol()
         val expectedType = nameExpression.getExpectedType()
 
-        val scopesContext = basicContext.originalKtFile.getScopeContextForPosition(nameExpression)
+        val scopesContext = originalKtFile.getScopeContextForPosition(nameExpression)
 
         val extensionChecker = ExtensionApplicabilityChecker {
-            it.checkExtensionIsSuitable(basicContext.originalKtFile, nameExpression, explicitReceiver)
+            it.checkExtensionIsSuitable(originalKtFile, nameExpression, explicitReceiver)
         }
 
         val visibilityChecker = CompletionVisibilityChecker {
-            basicContext.parameters.invocationCount > 1 || isVisible(
+            parameters.invocationCount > 1 || isVisible(
                 it,
                 fileSymbol,
                 positionContext.explicitReceiver,
@@ -188,14 +188,12 @@ private class KotlinWithNameReferenceCompletionProvider(
 
         when {
             nameExpression.parent is KtUserType -> collectTypesCompletion(
-                basicContext.result,
                 scopesContext.scopes,
                 expectedType,
                 visibilityChecker
             )
             explicitReceiver != null -> {
                 collectDotCompletion(
-                    basicContext.result,
                     scopesContext.scopes,
                     explicitReceiver,
                     expectedType,
@@ -204,13 +202,12 @@ private class KotlinWithNameReferenceCompletionProvider(
                 )
             }
 
-            else -> collectDefaultCompletion(basicContext.result, scopesContext, expectedType, extensionChecker, visibilityChecker)
+            else -> collectDefaultCompletion(scopesContext, expectedType, extensionChecker, visibilityChecker)
         }
     }
 
 
     private fun KtAnalysisSession.collectTypesCompletion(
-        result: CompletionResultSet,
         implicitScopes: KtScope,
         expectedType: KtType?,
         visibilityChecker: CompletionVisibilityChecker,
@@ -229,7 +226,6 @@ private class KotlinWithNameReferenceCompletionProvider(
     }
 
     private fun KtAnalysisSession.collectDotCompletion(
-        result: CompletionResultSet,
         implicitScopes: KtCompositeScope,
         explicitReceiver: KtExpression,
         expectedType: KtType?,
@@ -250,7 +246,6 @@ private class KotlinWithNameReferenceCompletionProvider(
     }
 
     private fun KtAnalysisSession.collectDefaultCompletion(
-        result: CompletionResultSet,
         implicitScopesContext: KtScopeContext,
         expectedType: KtType?,
         extensionChecker: ExtensionApplicabilityChecker,
@@ -275,7 +270,7 @@ private class KotlinWithNameReferenceCompletionProvider(
         collectTopLevelExtensionsFromIndices(implicitReceiversTypes, extensionChecker, visibilityChecker)
             .forEach { addSymbolToCompletion(result, expectedType, it) }
 
-        collectTypesCompletion(result, implicitScopes, expectedType, visibilityChecker)
+        collectTypesCompletion(implicitScopes, expectedType, visibilityChecker)
     }
 
     private fun KtAnalysisSession.collectTopLevelExtensionsFromIndices(

idea/idea-fir/src/org/jetbrains/kotlin/idea/completion/context/FirBasicCompletionContext.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.idea.completion.context
 
 import com.intellij.codeInsight.completion.CompletionParameters
 import com.intellij.codeInsight.completion.CompletionResultSet
+import com.intellij.codeInsight.completion.PrefixMatcher
 import com.intellij.openapi.project.Project
 import org.jetbrains.kotlin.idea.project.TargetPlatformDetector
 import org.jetbrains.kotlin.platform.TargetPlatform
@@ -15,6 +16,7 @@ import org.jetbrains.kotlin.psi.KtFile
 internal class FirBasicCompletionContext(
     val parameters: CompletionParameters,
     val result: CompletionResultSet,
+    val prefixMatcher: PrefixMatcher,
     val originalKtFile: KtFile,
     val fakeKtFile: KtFile,
     val project: Project,
@@ -22,11 +24,12 @@ internal class FirBasicCompletionContext(
 ) {
     companion object {
         fun createFromParameters(parameters: CompletionParameters, result: CompletionResultSet): FirBasicCompletionContext? {
+            val prefixMatcher = result.prefixMatcher
             val originalKtFile = parameters.originalFile as? KtFile ?: return null
             val fakeKtFile = parameters.position.containingFile as? KtFile ?: return null
             val targetPlatform = TargetPlatformDetector.getPlatform(originalKtFile)
             val project = originalKtFile.project
-            return FirBasicCompletionContext(parameters, result, originalKtFile, fakeKtFile, project, targetPlatform)
+            return FirBasicCompletionContext(parameters, result, prefixMatcher, originalKtFile, fakeKtFile, project, targetPlatform)
         }
     }
 }

idea/idea-fir/src/org/jetbrains/kotlin/idea/completion/contributors/FirCompletionContributorBase.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.idea.completion.contributors
+
+import com.intellij.codeInsight.completion.CompletionParameters
+import com.intellij.codeInsight.completion.CompletionResultSet
+import com.intellij.codeInsight.completion.PrefixMatcher
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.idea.completion.context.FirBasicCompletionContext
+import org.jetbrains.kotlin.platform.TargetPlatform
+import org.jetbrains.kotlin.psi.KtFile
+
+internal abstract class FirCompletionContributorBase(protected val basicContext: FirBasicCompletionContext) {
+    protected val prefixMatcher: PrefixMatcher get() = basicContext.prefixMatcher
+    protected val parameters: CompletionParameters get() = basicContext.parameters
+    protected val result: CompletionResultSet get() = basicContext.result
+    protected val originalKtFile: KtFile get() = basicContext.originalKtFile
+    protected val fakeKtFile: KtFile get() = basicContext.fakeKtFile
+    protected val project: Project get() = basicContext.project
+    protected val targetPlatform: TargetPlatform get() = basicContext.targetPlatform
+}