SnapshotValueReader

[Trickybrain]

To take step in #7

SnapshotValueReader Test

selfie-python-wip/jvm/selfie-lib/src/jvmTest/kotlin/com/diffplug/selfie/SnapshotValueReaderTest.kt

Lines 22 to 175 in 2aededc

	class SnapshotValueReaderTest {
	@Test
	fun noEscapingNeeded() {
	val reader =
	SnapshotValueReader.of(
	"""
	╔═ 00_empty ═╗
	╔═ 01_singleLineString ═╗
	this is one line
	╔═ 01a_singleLineLeadingSpace ═╗
	the leading space is significant
	╔═ 01b_singleLineTrailingSpace ═╗
	the trailing space is significant
	╔═ 02_multiLineStringTrimmed ═╗
	Line 1
	Line 2
	╔═ 03_multiLineStringTrailingNewline ═╗
	Line 1
	Line 2
	╔═ 04_multiLineStringLeadingNewline ═╗
	Line 1
	Line 2
	╔═ 05_notSureHowKotlinMultilineWorks ═╗
	"""
	.trimIndent())
	reader.peekKey() shouldBe "00_empty"
	reader.peekKey() shouldBe "00_empty"
	reader.nextValue().valueString() shouldBe ""
	reader.peekKey() shouldBe "01_singleLineString"
	reader.peekKey() shouldBe "01_singleLineString"
	reader.nextValue().valueString() shouldBe "this is one line"
	reader.peekKey() shouldBe "01a_singleLineLeadingSpace"
	reader.nextValue().valueString() shouldBe " the leading space is significant"
	reader.peekKey() shouldBe "01b_singleLineTrailingSpace"
	reader.nextValue().valueString() shouldBe "the trailing space is significant "
	reader.peekKey() shouldBe "02_multiLineStringTrimmed"
	reader.nextValue().valueString() shouldBe "Line 1\nLine 2"
	// note that leading and trailing newlines in the snapshots are significant
	// this is critical so that snapshots can accurately capture the exact number of newlines
	reader.peekKey() shouldBe "03_multiLineStringTrailingNewline"
	reader.nextValue().valueString() shouldBe "Line 1\nLine 2\n"
	reader.peekKey() shouldBe "04_multiLineStringLeadingNewline"
	reader.nextValue().valueString() shouldBe "\nLine 1\nLine 2"
	reader.peekKey() shouldBe "05_notSureHowKotlinMultilineWorks"
	reader.nextValue().valueString() shouldBe ""
	}
	@Test
	fun invalidNames() {
	shouldThrow<ParseException> { SnapshotValueReader.of("╔═name ═╗").peekKey() }
	.let { it.message shouldBe "L1:Expected to start with '╔═ '" }
	shouldThrow<ParseException> { SnapshotValueReader.of("╔═ name═╗").peekKey() }
	.let { it.message shouldBe "L1:Expected to contain ' ═╗'" }
	shouldThrow<ParseException> { SnapshotValueReader.of("╔═ name ═╗").peekKey() }
	.let { it.message shouldBe "L1:Leading spaces are disallowed: ' name'" }
	shouldThrow<ParseException> { SnapshotValueReader.of("╔═ name ═╗").peekKey() }
	.let { it.message shouldBe "L1:Trailing spaces are disallowed: 'name '" }
	SnapshotValueReader.of("╔═ name ═╗ comment okay").peekKey() shouldBe "name"
	SnapshotValueReader.of("╔═ name ═╗okay here too").peekKey() shouldBe "name"
	SnapshotValueReader.of("╔═ name ═╗ okay ╔═ ═╗ (it's the first ' ═╗' that counts)")
	.peekKey() shouldBe "name"
	}
	@Test
	fun escapeCharactersInName() {
	val reader =
	SnapshotValueReader.of(
	"""
	╔═ test with \(square brackets\) in name ═╗
	╔═ test with \\backslash\\ in name ═╗
	╔═ test with\nnewline\nin name ═╗
	╔═ test with \ttab\t in name ═╗
	╔═ test with \┌\─ ascii art \─\┐ in name ═╗
	"""
	.trimIndent())
	reader.peekKey() shouldBe "test with [square brackets] in name"
	reader.nextValue().valueString() shouldBe ""
	reader.peekKey() shouldBe """test with \backslash\ in name"""
	reader.nextValue().valueString() shouldBe ""
	reader.peekKey() shouldBe
	"""
	test with
	newline
	in name
	"""
	.trimIndent()
	reader.nextValue().valueString() shouldBe ""
	reader.peekKey() shouldBe "test with \ttab\t in name"
	reader.nextValue().valueString() shouldBe ""
	reader.peekKey() shouldBe "test with ╔═ ascii art ═╗ in name"
	reader.nextValue().valueString() shouldBe ""
	}
	@Test
	fun escapeCharactersInBody() {
	val reader =
	SnapshotValueReader.of(
	"""
	╔═ ascii art okay ═╗
	╔══╗
	╔═ escaped iff on first line ═╗
	𐝁══╗
	╔═ body escape characters ═╗
	𐝃𐝁𐝃𐝃 linear a is dead
	"""
	.trimIndent())
	reader.peekKey() shouldBe "ascii art okay"
	reader.nextValue().valueString() shouldBe """ ╔══╗"""
	reader.peekKey() shouldBe "escaped iff on first line"
	reader.nextValue().valueString() shouldBe """╔══╗"""
	reader.peekKey() shouldBe "body escape characters"
	reader.nextValue().valueString() shouldBe """𐝁𐝃 linear a is dead"""
	}
	@Test
	fun skipValues() {
	val testContent =
	"""
	╔═ 00_empty ═╗
	╔═ 01_singleLineString ═╗
	this is one line
	╔═ 02_multiLineStringTrimmed ═╗
	Line 1
	Line 2
	╔═ 05_notSureHowKotlinMultilineWorks ═╗
	"""
	.trimIndent()
	assertKeyValueWithSkip(testContent, "00_empty", "")
	assertKeyValueWithSkip(testContent, "01_singleLineString", "this is one line")
	assertKeyValueWithSkip(testContent, "02_multiLineStringTrimmed", "Line 1\nLine 2")
	}
	private fun assertKeyValueWithSkip(input: String, key: String, value: String) {
	val reader = SnapshotValueReader.of(input)
	while (reader.peekKey() != key) {
	reader.skipValue()
	}
	reader.peekKey() shouldBe key
	reader.nextValue().valueString() shouldBe value
	while (reader.peekKey() != null) {
	reader.skipValue()
	}
	}
	@Test
	fun binary() {
	val reader = SnapshotValueReader.of("""╔═ Apple ═╗ base64 length 3 bytes
	c2Fk
	""")
	reader.peekKey() shouldBe "Apple"
	reader.nextValue().valueBinary() shouldBe "sad".toByteArray()
	}
	}

SnapshotValueReader

selfie-python-wip/jvm/selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/SnapshotFile.kt

Lines 283 to 390 in 2aededc

	class SnapshotValueReader(val lineReader: LineReader) {
	var line: String? = null
	val unixNewlines = lineReader.unixNewlines()
	/** The key of the next value, does not increment anything about the reader's state. */
	fun peekKey(): String? {
	return nextKey()
	}
	/** Reads the next value. */
	@OptIn(ExperimentalEncodingApi::class)
	fun nextValue(): SnapshotValue {
	// validate key
	nextKey()
	val isBase64 = nextLine()!!.contains(FLAG_BASE64)
	resetLine()
	// read value
	val buffer = StringBuilder()
	scanValue { line ->
	if (line.length >= 2 && line[0] == '\uD801' && line[1] == '\uDF41') { // "\uD801\uDF41" = "𐝁"
	buffer.append(KEY_FIRST_CHAR)
	buffer.append(line, 2, line.length)
	} else {
	buffer.append(line)
	}
	buffer.append('\n')
	}
	val rawString =
	if (buffer.isEmpty()) ""
	else {
	buffer.setLength(buffer.length - 1)
	buffer.toString()
	}
	return if (isBase64) SnapshotValue.of(Base64.Mime.decode(rawString))
	else SnapshotValue.of(bodyEsc.unescape(rawString))
	}
	/** Same as nextValue, but faster. */
	fun skipValue() {
	// Ignore key
	nextKey()
	resetLine()
	scanValue {
	// ignore it
	}
	}
	private inline fun scanValue(consumer: (String) -> Unit) {
	// read next
	var nextLine = nextLine()
	while (nextLine != null && nextLine.indexOf(KEY_FIRST_CHAR) != 0) {
	resetLine()
	consumer(nextLine)
	// read next
	nextLine = nextLine()
	}
	}
	private fun nextKey(): String? {
	val line = nextLine() ?: return null
	val startIndex = line.indexOf(KEY_START)
	val endIndex = line.indexOf(KEY_END)
	if (startIndex == -1) {
	throw ParseException(lineReader, "Expected to start with '$KEY_START'")
	}
	if (endIndex == -1) {
	throw ParseException(lineReader, "Expected to contain '$KEY_END'")
	}
	// valid key
	val key = line.substring(startIndex + KEY_START.length, endIndex)
	return if (key.startsWith(" ")) {
	throw ParseException(lineReader, "Leading spaces are disallowed: '$key'")
	} else if (key.endsWith(" ")) {
	throw ParseException(lineReader, "Trailing spaces are disallowed: '$key'")
	} else {
	nameEsc.unescape(key)
	}
	}
	private fun nextLine(): String? {
	if (line == null) {
	line = lineReader.readLine()
	}
	return line
	}
	private fun resetLine() {
	line = null
	}
	companion object {
	fun of(content: String) = SnapshotValueReader(LineReader.forString(content))
	fun of(content: ByteArray) = SnapshotValueReader(LineReader.forBinary(content))
	private const val KEY_FIRST_CHAR = '╔'
	private const val KEY_START = "╔═ "
	private const val KEY_END = " ═╗"
	private const val FLAG_BASE64 = " ═╗ base64"
	/**
	* https://github.com/diffplug/selfie/blob/main/jvm/selfie-lib/src/commonTest/resources/com/diffplug/selfie/scenarios_and_lenses.ss
	*/
	internal val nameEsc = PerCharacterEscaper.specifiedEscape("\\\\[(])\nn\tt╔┌╗┐═─")
	/** https://github.com/diffplug/selfie/issues/2 */
	internal val bodyEsc = PerCharacterEscaper.selfEscape("\uD801\uDF43\uD801\uDF41")
	}
	}

[nedtwigg]

Closed by #44