Add support for multiline java (#87)

selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/Mode.kt

@@ -29,7 +29,7 @@ enum class Mode {
         readonly -> {
           if (storage.sourceFileHasWritableComment(call)) {
             val layout = storage.layout
-            val path = layout.sourcePathForCall(call.location)!!
+            val path = layout.sourcePathForCall(call.location)
             val (comment, line) = CommentTracker.commentString(path, storage.fs)
             throw storage.fs.assertFailed(
                 "Selfie is in readonly mode, so `$comment` is illegal at ${call.location.withLine(line).ideLink(layout)}")

selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/guts/Literals.kt

@@ -17,6 +17,8 @@ package com.diffplug.selfie.guts
 
 import kotlin.math.abs
 
+internal expect fun jreVersion(): Int
+
 enum class Language {
   JAVA,
   JAVA_PRE15,
@@ -28,7 +30,7 @@ enum class Language {
   companion object {
     fun fromFilename(filename: String): Language {
       return when (filename.substringAfterLast('.')) {
-        "java" -> JAVA_PRE15 // TODO: detect JRE and use JAVA if JVM >= 15
+        "java" -> if (jreVersion() < 15) JAVA_PRE15 else JAVA
         "kt" -> KOTLIN
         "groovy",
         "gvy",
@@ -101,14 +103,24 @@ internal object LiteralLong : LiteralFormat<Long>() {
   }
 }
 
+private const val TRIPLE_QUOTE = "\"\"\""
+
 internal object LiteralString : LiteralFormat<String>() {
-  override fun encode(value: String, language: Language): String {
-    return singleLineJavaToSource(value)
-  }
-  override fun parse(str: String, language: Language): String {
-    return singleLineJavaFromSource(str)
-  }
-  private fun singleLineJavaToSource(value: String): String {
+  override fun encode(value: String, language: Language): String =
+      if (value.indexOf('\n') == -1) singleLineJavaToSource(value)
+      else
+          when (language) {
+            Language.GROOVY,
+            Language.SCALA,
+            Language.CLOJURE,
+            Language.JAVA_PRE15 -> singleLineJavaToSource(value)
+            Language.JAVA -> multiLineJavaToSource(value)
+            Language.KOTLIN -> multiLineJavaToSource(value)
+          }
+  override fun parse(str: String, language: Language): String =
+      if (str.startsWith(TRIPLE_QUOTE)) multiLineJavaFromSource(str)
+      else singleLineJavaFromSource(str)
+  fun singleLineJavaToSource(value: String): String {
     val source = StringBuilder()
     source.append("\"")
     for (char in value) {
@@ -134,34 +146,92 @@ internal object LiteralString : LiteralFormat<String>() {
   private fun isControlChar(c: Char): Boolean {
     return c in '\u0000'..'\u001F' || c == '\u007F'
   }
-  private fun singleLineJavaFromSource(source: String): String {
+  fun multiLineJavaToSource(arg: String): String {
+    val escapeBackslashes = arg.replace("\\", "\\\\")
+    val escapeTripleQuotes = escapeBackslashes.replace(TRIPLE_QUOTE, "\\\"\\\"\\\"")
+    val protectWhitespace =
+        escapeTripleQuotes.lines().joinToString("\n") { line ->
+          val protectTrailingWhitespace =
+              if (line.endsWith(" ")) {
+                line.dropLast(1) + "\\s"
+              } else if (line.endsWith("\t")) {
+                line.dropLast(1) + "\\t"
+              } else line
+          val protectLeadingWhitespace =
+              if (protectTrailingWhitespace.startsWith(" ")) {
+                "\\s" + protectTrailingWhitespace.drop(1)
+              } else if (protectTrailingWhitespace.startsWith("\t")) {
+                "\\t" + protectTrailingWhitespace.drop(1)
+              } else protectTrailingWhitespace
+          protectLeadingWhitespace
+        }
+    return "$TRIPLE_QUOTE\n$protectWhitespace$TRIPLE_QUOTE"
+  }
+  fun singleLineJavaFromSource(sourceWithQuotes: String): String {
+    check(sourceWithQuotes.startsWith('"'))
+    check(sourceWithQuotes.endsWith('"'))
+    return unescapeJava(sourceWithQuotes.substring(1, sourceWithQuotes.length - 1))
+  }
+  private fun unescapeJava(source: String): String {
+    val firstEscape = source.indexOf('\\')
+    if (firstEscape == -1) {
+      return source
+    }
     val value = StringBuilder()
-    var i = 0
+    value.append(source.substring(0, firstEscape))
+    var i = firstEscape
     while (i < source.length) {
       var c = source[i]
       if (c == '\\') {
         i++
         c = source[i]
         when (c) {
+          '\"' -> value.append('\"')
+          '\\' -> value.append('\\')
           'b' -> value.append('\b')
+          'f' -> value.append('\u000c')
           'n' -> value.append('\n')
           'r' -> value.append('\r')
+          's' -> value.append(' ')
           't' -> value.append('\t')
-          '\"' -> value.append('\"')
-          '\\' -> value.append('\\')
           'u' -> {
             val code = source.substring(i + 1, i + 5).toInt(16)
             value.append(code.toChar())
             i += 4
           }
+          else -> throw IllegalArgumentException("Unknown escape sequence $c")
         }
-      } else if (c != '\"') {
+      } else {
         value.append(c)
       }
       i++
     }
     return value.toString()
   }
+  fun multiLineJavaFromSource(sourceWithQuotes: String): String {
+    check(sourceWithQuotes.startsWith("$TRIPLE_QUOTE\n"))
+    check(sourceWithQuotes.endsWith(TRIPLE_QUOTE))
+    val source =
+        sourceWithQuotes.substring(
+            TRIPLE_QUOTE.length + 1, sourceWithQuotes.length - TRIPLE_QUOTE.length)
+    val lines = source.lines()
+    val commonPrefix =
+        lines
+            .mapNotNull { line ->
+              if (line.isNotBlank()) line.takeWhile { it.isWhitespace() } else null
+            }
+            .minOrNull() ?: ""
+    return lines.joinToString("\n") { line ->
+      if (line.isBlank()) {
+        ""
+      } else {
+        val removedPrefix = if (commonPrefix.isEmpty()) line else line.removePrefix(commonPrefix)
+        val removeTrailingWhitespace = removedPrefix.trimEnd()
+        val handleEscapeSequences = unescapeJava(removeTrailingWhitespace)
+        handleEscapeSequences
+      }
+    }
+  }
 }
 
 internal object LiteralBoolean : LiteralFormat<Boolean>() {

selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/guts/SnapshotStorage.kt

@@ -57,5 +57,6 @@ interface SnapshotFileLayout {
   val rootFolder: Path
   val fs: FS
   val allowMultipleEquivalentWritesToOneLocation: Boolean
-  fun sourcePathForCall(call: CallLocation): Path?
+  fun sourcePathForCall(call: CallLocation): Path
+  fun sourcePathForCallMaybe(call: CallLocation): Path?
 }

selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/guts/WriteTracker.kt

@@ -83,9 +83,7 @@ class InlineWriteTracker : WriteTracker<CallLocation, LiteralValue<*>>() {
     recordInternal(call.location, literalValue, call, layout)
     // assert that the value passed at runtime matches the value we parse at compile time
     // because if that assert fails, we've got no business modifying test code
-    val file =
-        layout.sourcePathForCall(call.location)
-            ?: throw Error("Unable to find source file for ${call.location.ideLink(layout)}")
+    val file = layout.sourcePathForCall(call.location)
     if (literalValue.expected != null) {
       // if expected == null, it's a `toBe_TODO()`, so there's nothing to check
       val content = SourceFile(layout.fs.name(file), layout.fs.fileRead(file))

selfie-lib/src/commonTest/kotlin/com/diffplug/selfie/guts/LiteralStringTest.kt

@@ -20,42 +20,48 @@ import kotlin.test.Test
 
 class LiteralStringTest {
   @Test
-  fun encode() {
-    encode(
-        "1",
-        """
-      "1"
-    """
-            .trimIndent())
-    encode(
-        "1\n\tABC",
-        """
-      "1\n\tABC"
-    """
-            .trimIndent())
-  }
-  private fun encode(value: String, expected: String) {
-    val actual = LiteralString.encode(value, Language.JAVA)
+  fun singleLineJavaToSource() {
+    singleLineJavaToSource("1", "'1'")
+    singleLineJavaToSource("\\", "'\\\\'")
+    singleLineJavaToSource("1\n\tABC", "'1\\n\\tABC'")
+  }
+  private fun singleLineJavaToSource(value: String, expected: String) {
+    val actual = LiteralString.singleLineJavaToSource(value)
+    actual shouldBe expected.replace("'", "\"")
+  }
+
+  @Test
+  fun multiLineJavaToSource() {
+    multiLineJavaToSource("1", "'''\n1'''")
+    multiLineJavaToSource("\\", "'''\n\\\\'''")
+    multiLineJavaToSource("  leading\ntrailing  ", "'''\n" + "\\s leading\n" + "trailing \\s'''")
+  }
+  private fun multiLineJavaToSource(value: String, expected: String) {
+    val actual = LiteralString.multiLineJavaToSource(value)
+    actual shouldBe expected.replace("'", "\"")
+  }
+
+  @Test
+  fun singleLineJavaFromSource() {
+    singleLineJavaFromSource("1", "1")
+    singleLineJavaFromSource("\\\\", "\\")
+    singleLineJavaFromSource("1\\n\\tABC", "1\n\tABC")
+  }
+  private fun singleLineJavaFromSource(value: String, expected: String) {
+    val actual = LiteralString.singleLineJavaFromSource("\"${value.replace("'", "\"")}\"")
     actual shouldBe expected
   }
 
   @Test
-  fun decode() {
-    decode(
-        """
-      "1"
-    """
-            .trimIndent(),
-        "1")
-    decode(
-        """
-      "1\n\tABC"
-    """
-            .trimIndent(),
-        "1\n\tABC")
-  }
-  private fun decode(value: String, expected: String) {
-    val actual = LiteralString.parse(value, Language.JAVA)
+  fun multiLineJavaFromSource() {
+    multiLineJavaFromSource("\n123\nabc", "123\nabc")
+    multiLineJavaFromSource("\n  123\n  abc", "123\nabc")
+    multiLineJavaFromSource("\n  123  \n  abc\t", "123\nabc")
+    multiLineJavaFromSource("\n  123  \n  abc\t", "123\nabc")
+    multiLineJavaFromSource("\n  123  \\s\n  abc\t\\s", "123   \nabc\t ")
+  }
+  private fun multiLineJavaFromSource(value: String, expected: String) {
+    val actual = LiteralString.multiLineJavaFromSource("\"\"\"${value.replace("'", "\"")}\"\"\"")
     actual shouldBe expected
   }
 }

selfie-lib/src/jsMain/kotlin/com/diffplug/selfie/guts/Literals.js.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2024 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.selfie.guts
+
+/**
+ * If the user is hip enough to run javascript, they're probably hip enough for multiline string
+ * literals.
+ */
+internal actual fun jreVersion(): Int = 15

selfie-lib/src/jvmMain/kotlin/com/diffplug/selfie/guts/Literals.jvm.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2024 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.selfie.guts
+
+internal actual fun jreVersion(): Int {
+  val versionStr = System.getProperty("java.version")
+  return if (versionStr.startsWith("1.")) {
+    if (versionStr.startsWith("1.8")) 8 else throw Error("Unsupported java version: $versionStr")
+  } else {
+    versionStr.substringBefore('.').toInt()
+  }
+}

selfie-lib/src/jvmMain/kotlin/com/diffplug/selfie/guts/WriteTracker.jvm.kt

@@ -40,7 +40,7 @@ actual data class CallLocation(
     if (fileName != null) {
       return fileName
     }
-    return layout.sourcePathForCall(this)?.let { layout.fs.name(it) }
+    return layout.sourcePathForCallMaybe(this)?.let { layout.fs.name(it) }
         ?: "${clazz.substringAfterLast('.')}.class"
   }
 

selfie-lib/src/jvmTest/kotlin/testpkg/RecordCallTest.kt

@@ -37,6 +37,7 @@ class RecordCallTest {
           override val allowMultipleEquivalentWritesToOneLocation: Boolean
             get() = TODO()
           override fun sourcePathForCall(call: CallLocation) = Path("testpkg/RecordCallTest.kt")
+          override fun sourcePathForCallMaybe(call: CallLocation): Path? = sourcePathForCall(call)
         }
     stack.location.ideLink(layout) shouldBe
         "testpkg.RecordCallTest.testRecordCall(RecordCallTest.kt:30)"

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieSettingsAPI.kt

@@ -50,6 +50,24 @@ open class SelfieSettingsAPI {
           "Could not find a standard test directory, 'user.dir' is equal to $userDir, looked in $STANDARD_DIRS")
     }
 
+  /**
+   * If Selfie should look for test sourcecode in places other than the rootFolder, you can specify
+   * them here.
+   */
+  open val otherSourceRoots: List<File>
+    get() {
+      return buildList {
+        val rootDir = rootFolder
+        val userDir = File(System.getProperty("user.dir"))
+        for (standardDir in STANDARD_DIRS) {
+          val candidate = userDir.resolve(standardDir)
+          if (candidate.isDirectory && candidate != rootDir) {
+            add(candidate)
+          }
+        }
+      }
+    }
+
   internal companion object {
     private val STANDARD_DIRS =
         listOf(

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SnapshotFileLayoutJUnit5.kt

@@ -23,13 +23,21 @@ import com.diffplug.selfie.guts.SnapshotFileLayout
 class SnapshotFileLayoutJUnit5(settings: SelfieSettingsAPI, override val fs: FS) :
     SnapshotFileLayout {
   override val rootFolder = settings.rootFolder
+  private val otherSourceRoots = settings.otherSourceRoots
   override val allowMultipleEquivalentWritesToOneLocation =
       settings.allowMultipleEquivalentWritesToOneLocation
   val snapshotFolderName = settings.snapshotFolderName
   internal val unixNewlines = inferDefaultLineEndingIsUnix(settings.rootFolder, fs)
   val extension: String = ".ss"
   private val cache = ThreadLocal<Pair<CallLocation, Path>?>()
-  override fun sourcePathForCall(call: CallLocation): Path? {
+  override fun sourcePathForCall(call: CallLocation): Path {
+    val nonNull =
+        sourcePathForCallMaybe(call)
+            ?: throw fs.assertFailed(
+                "Couldn't find source file for $call, looked in $rootFolder and $otherSourceRoots, maybe there are other source roots?")
+    return nonNull
+  }
+  override fun sourcePathForCallMaybe(call: CallLocation): Path? {
     val cached = cache.get()
     if (cached?.first?.samePathAs(call) == true) {
       return cached.second
@@ -41,16 +49,22 @@ class SnapshotFileLayoutJUnit5(settings: SelfieSettingsAPI, override val fs: FS)
       path
     }
   }
-  private fun computePathForCall(call: CallLocation): Path? {
+  private fun computePathForCall(call: CallLocation): Path? =
+      sequence {
+            yield(rootFolder)
+            yieldAll(otherSourceRoots)
+          }
+          .firstNotNullOfOrNull { computePathForCall(it, call) }
+  private fun computePathForCall(folder: Path, call: CallLocation): Path? {
     if (call.fileName != null) {
-      return fs.fileWalk(rootFolder) { walk ->
+      return fs.fileWalk(folder) { walk ->
         walk.filter { fs.name(it) == call.fileName }.firstOrNull()
       }
     }
     val fileWithoutExtension = call.clazz.substringAfterLast('.').substringBefore('$')
     val likelyExtensions = listOf("kt", "java", "scala", "groovy", "clj", "cljc")
     val possibleNames = likelyExtensions.map { "$fileWithoutExtension.$it" }.toSet()
-    return fs.fileWalk(rootFolder) { walk ->
+    return fs.fileWalk(folder) { walk ->
       walk.filter { fs.name(it) in possibleNames }.firstOrNull()
     }
   }