KT-5193 Make multiline strings foldable (#938)

* KT-5193 Make multiline strings foldable
 #KT-5193 Fixed

* Avoid multiple replace call

idea/src/org/jetbrains/kotlin/idea/KotlinFoldingBuilder.kt

@@ -81,7 +81,8 @@ class KotlinFoldingBuilder : CustomFoldingBuilder(), DumbAware {
         val parentType = node.treeParent?.elementType
         return type == KtNodeTypes.FUNCTION_LITERAL ||
                (type == KtNodeTypes.BLOCK && parentType != KtNodeTypes.FUNCTION_LITERAL) ||
-               type == KtNodeTypes.CLASS_BODY || type == KtTokens.BLOCK_COMMENT || type == KDocTokens.KDOC
+               type == KtNodeTypes.CLASS_BODY || type == KtTokens.BLOCK_COMMENT || type == KDocTokens.KDOC ||
+               type == KtNodeTypes.STRING_TEMPLATE
     }
 
     private fun getRangeToFold(node: ASTNode): TextRange {
@@ -99,10 +100,18 @@ class KotlinFoldingBuilder : CustomFoldingBuilder(), DumbAware {
     override fun getLanguagePlaceholderText(node: ASTNode, range: TextRange): String = when {
         node.elementType == KtTokens.BLOCK_COMMENT -> "/${getFirstLineOfComment(node)}.../"
         node.elementType == KDocTokens.KDOC -> "/**${getFirstLineOfComment(node)}...*/"
+        node.elementType == KtNodeTypes.STRING_TEMPLATE -> "\"\"\"${getFirstLineOfString(node)}...\"\"\""
         node.psi is KtImportList -> "..."
         else ->  "{...}"
     }
 
+    private fun getFirstLineOfString(node: ASTNode): String {
+        val targetStringLine = node.text.split("\n").asSequence().map {
+            it.replace("\"\"\"", "")
+        }.firstOrNull(String::isNotBlank) ?: return ""
+        return " ${targetStringLine.replace("\"\"\"", "").trim()} "
+    }
+
     private fun getFirstLineOfComment(node: ASTNode): String {
         val targetCommentLine = node.text.split("\n").firstOrNull {
             getCommentContents(it).isNotEmpty()

idea/testData/folding/checkCollapse/multilineStrings.kt

@@ -0,0 +1,32 @@
+val result1 = <fold text='""" 14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 1.0, 0.25, 1.0, 0.5, 2.0, 3.0, 3.0 ..."""' expand='true'>"""
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 1.0, 0.25, 1.0, 0.5, 2.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 4.0, 1.0, 0.5, 1.0, 1.0, 3.0, 4.0, 3.0, 0.25, 3.0, 0.5, 3.0, 3.0, 2.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 2.0, 2.0, 1.0, 0.5, 1.0, 0.5, 2.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 1.0, 0.25, 1.0, 0.5, 3.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 2.0, 0.5, 2.0, 0.5, 3.0, 3.0, 2.5
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 2.0, 2.0, 1.0, 0.3333333333333333, 3.0, 0.5, 2.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 2.0, 2.0, 3.0, 0.3333333333333333, 1.0, 0.5, 3.0, 2.0, 2.5
+  14.55576559546314  -  0.25, 4.0, 1.0, 0.5, 1.0, 1.0, 3.0, 4.0, 3.0, 0.3333333333333333, 1.0, 0.5, 3.0, 3.0, 2.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 2.0, 0.5, 2.0, 0.5, 3.0, 2.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 3.0, 2.0, 2.0, 0.5, 1.0, 0.5, 2.0, 2.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 3.0, 0.5, 2.0, 0.5, 2.0, 3.0, 2.5
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 2.0, 2.0, 1.0, 0.5, 3.0, 0.5, 1.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 3.0, 2.0, 3.0, 0.5, 3.0, 0.5, 3.0, 2.0, 2.5
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.3333333333333333, 1.0, 2.0, 1.0, 0.3333333333333333, 2.0, 0.5, 1.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 3.0, 2.0, 1.0, 0.5, 2.0, 0.5, 1.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 1.0, 0.25, 2.0, 0.5, 2.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 1.0, 0.3333333333333333, 2.0, 0.5, 3.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 2.0, 0.25, 2.0, 0.5, 3.0, 2.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 2.0, 0.3333333333333333, 2.0, 0.5, 3.0, 2.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 2.0, 0.5, 3.0, 0.5, 1.0, 3.0, 3.0
+  14.55576559546314  -  0.25, 3.0, 0.25, 0.25, 1.0, 0.25, 1.0, 2.0, 3.0, 0.3333333333333333, 1.0, 0.5, 3.0, 3.0, 2.5
+"""</fold>
+
+val result2 = <fold text='""" other multiline string ..."""' expand='true'>"""other multiline string
+without spaces
+"""</fold>
+
+val empty = <fold text='"""..."""' expand='true'>"""
+
+
+"""</fold>

idea/testData/folding/noCollapse/singleLineString.kt

@@ -0,0 +1,6 @@
+val result3 = """aaa"""
+val result4 = "bbb"
+val result5 = "ccc" +
+              "ddd"
+val result6 = "eee" +
+              """fff"""

idea/tests/org/jetbrains/kotlin/idea/folding/KotlinFoldingTestGenerated.java

@@ -78,6 +78,12 @@ public class KotlinFoldingTestGenerated extends AbstractKotlinFoldingTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/folding/noCollapse/oneImport.kt");
             doTest(fileName);
         }
+
+        @TestMetadata("singleLineString.kt")
+        public void testSingleLineString() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/folding/noCollapse/singleLineString.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/folding/checkCollapse")
@@ -117,5 +123,11 @@ public class KotlinFoldingTestGenerated extends AbstractKotlinFoldingTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/folding/checkCollapse/imports.kt");
             doSettingsFoldingTest(fileName);
         }
+
+        @TestMetadata("multilineStrings.kt")
+        public void testMultilineStrings() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/folding/checkCollapse/multilineStrings.kt");
+            doSettingsFoldingTest(fileName);
+        }
     }
 }