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Adds ISL model #251

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merged 1 commit into from
Apr 22, 2023
Merged

Adds ISL model #251

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156 changes: 3 additions & 153 deletions ion-schema/src/main/kotlin/com/amazon/ionschema/internal/constraint/Regex.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ import com.amazon.ionschema.IonSchemaVersion
import com.amazon.ionschema.Violation
import com.amazon.ionschema.Violations
import com.amazon.ionschema.internal.util.islRequire
import com.amazon.ionschema.internal.util.validateRegexPattern
import java.util.regex.Pattern

/**
Expand Down Expand Up @@ -59,8 +60,8 @@ internal class Regex(
}
flags = flags.or(flag)
}

pattern = toPattern(ion.stringValue(), flags)
val patternString = validateRegexPattern(ion.stringValue(), islVersion)
pattern = Pattern.compile(patternString, flags)
}

override fun validate(value: IonValue, issues: Violations) {
Expand All @@ -75,155 +76,4 @@ internal class Regex(
}
}
}

private fun toPattern(string: String, flags: Int): Pattern {
val si = StringIterator(string)
val sb = StringBuilder()
var ch = si.next()
do {
when (ch) {
'[' -> {
sb.append(ch)
parseCharacterClass(si, sb)
}
'(' -> {
sb.append(ch)
ch = si.next()
if (ch == '?') { // error on "(?..." constructs
error(si, "invalid character '$ch'")
}
sb.append(ch)
}
'\\' -> { // handle escaped chars
ch = si.next()
when (ch) {
'.', '^', '$', '|', '?', '*', '+', '\\',
'[', ']', '(', ')', '{', '}',
'w', 'W', 'd', 'D' -> sb.append('\\').append(ch)
's' -> sb.append("[ \\f\\n\\r\\t]")
'S' -> sb.append("[^ \\f\\n\\r\\t]")
else -> error(si, "invalid escape character '$ch'")
}
}
else -> sb.append(ch) // otherwise, accept the character
}

parseQuantifier(si, sb) // parse a quantifier, if present

ch = si.next()
} while (ch != null)

return Pattern.compile(sb.toString(), flags)
}

private fun parseCharacterClass(si: StringIterator, sb: StringBuilder) {
do {
val ch = si.next()
sb.append(ch)

when (ch) {
'&' -> {
if (si.peek() == '&') {
error(si, "'&&' is not supported in a character class")
}
}

'[' -> error(si, "'[' must be escaped within a character class")

'\\' -> {
when (val ch2 = si.next()) {
'[', ']', '\\' -> sb.append(ch2)
'd', 's', 'w', 'D', 'S', 'W' -> if (islVersion == IonSchemaVersion.v1_0) {
// For Ion Schema 1.0, this is an error because ISL 1.0 does
// not support pre-defined char classes (i.e., \d, \s, \w)
// while user is specifying a new char class
error(si, "invalid sequence '\\$ch2' in character class")
} else {
// In Ion Schema 2.0, this is allowed
sb.append(ch2)
}
else -> error(
si,
"invalid sequence '\\$ch2' in character class"
)
}
}

']' -> return
}
} while (ch != null)

error(si, "character class missing ']'")
}

private fun parseQuantifier(si: StringIterator, sb: StringBuilder) {
val initialLength = sb.length
var ch = si.peek()
when (ch) {
'?', '*', '+' -> {
ch = si.next()
sb.append(ch)
}
'{' -> {
ch = si.next()
sb.append(ch)
var complete = false
// A quantifier such as {,3} is not an ECMA 262 quantifier (it has no lower bound)
// We track whether we've found a number so that we can ensure that a comma is only
// allowed if it follows at least one digit.
var foundAnyNumber = false
do {
ch = si.next()
when (ch) {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9' -> { sb.append(ch); foundAnyNumber = true }
',' -> if (foundAnyNumber) sb.append(ch) else error(si, "range quantifier is missing lower bound")
'}' -> {
sb.append(ch)
complete = true
}
null -> {}
else -> error(si, "invalid character '$ch'")
}
} while (ch != null && !complete)

if (!complete) {
error(si, "range quantifier missing '}'")
}
}
}

if (sb.length > initialLength && ch != null) {
ch = si.peek()
when (ch) {
'?' -> error(si, "invalid character '$ch'")
'+' -> error(si, "invalid character '$ch'")
}
}
}

private fun error(si: StringIterator, message: String): Unit =
throw InvalidSchemaException("$message in regex '$si' at offset ${si.currentIndex()}")
}

private class StringIterator(private val s: String) {
private var index = -1
val length = s.length

fun next(): Char? {
index += 1
return get(index)
}

fun peek() = get(index + 1)

private fun get(i: Int): Char? {
if (i < length) {
return s[i]
}
return null
}

fun currentIndex() = index

override fun toString() = s
}
157 changes: 157 additions & 0 deletions ion-schema/src/main/kotlin/com/amazon/ionschema/internal/util/regex.kt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,157 @@
package com.amazon.ionschema.internal.util

import com.amazon.ionschema.InvalidSchemaException
import com.amazon.ionschema.IonSchemaVersion

/**
* Validates that a regex pattern is valid for the subset of ECMA-262 that is supported by Ion Schema, and converts
* to the equivalent syntax for Java Regex.
*/
internal fun validateRegexPattern(string: String, islVersion: IonSchemaVersion = IonSchemaVersion.v2_0): String {
val si = StringIterator(string)
val sb = StringBuilder()
var ch = si.next()
do {
when (ch) {
'[' -> {
sb.append(ch)
parseCharacterClass(si, sb, islVersion)
}
'(' -> {
sb.append(ch)
ch = si.next()
if (ch == '?') { // error on "(?..." constructs
error(si, "invalid character '$ch'")
}
sb.append(ch)
}
'\\' -> { // handle escaped chars
ch = si.next()
when (ch) {
'.', '^', '$', '|', '?', '*', '+', '\\',
'[', ']', '(', ')', '{', '}',
'w', 'W', 'd', 'D' -> sb.append('\\').append(ch)
's' -> sb.append("[ \\f\\n\\r\\t]")
'S' -> sb.append("[^ \\f\\n\\r\\t]")
else -> error(si, "invalid escape character '$ch'")
}
}
else -> sb.append(ch) // otherwise, accept the character
}

parseQuantifier(si, sb) // parse a quantifier, if present

ch = si.next()
} while (ch != null)

return sb.toString() // Pattern.compile(sb.toString(), flags)
}

private fun parseCharacterClass(si: StringIterator, sb: StringBuilder, islVersion: IonSchemaVersion) {
do {
val ch = si.next()
sb.append(ch)

when (ch) {
'&' -> {
if (si.peek() == '&') {
error(si, "'&&' is not supported in a character class")
}
}

'[' -> error(si, "'[' must be escaped within a character class")

'\\' -> {
when (val ch2 = si.next()) {
'[', ']', '\\' -> sb.append(ch2)
'd', 's', 'w', 'D', 'S', 'W' -> if (islVersion == IonSchemaVersion.v1_0) {
// For Ion Schema 1.0, this is an error because ISL 1.0 does
// not support pre-defined char classes (i.e., \d, \s, \w)
// while user is specifying a new char class
error(si, "invalid sequence '\\$ch2' in character class")
} else {
// In Ion Schema 2.0, this is allowed
sb.append(ch2)
}
else -> error(
si,
"invalid sequence '\\$ch2' in character class"
)
}
}

']' -> return
}
} while (ch != null)

error(si, "character class missing ']'")
}
private fun parseQuantifier(si: StringIterator, sb: StringBuilder) {
val initialLength = sb.length
var ch = si.peek()
when (ch) {
'?', '*', '+' -> {
ch = si.next()
sb.append(ch)
}
'{' -> {
ch = si.next()
sb.append(ch)
var complete = false
// A quantifier such as {,3} is not an ECMA 262 quantifier (it has no lower bound)
// We track whether we've found a number so that we can ensure that a comma is only
// allowed if it follows at least one digit.
var foundAnyNumber = false
do {
ch = si.next()
when (ch) {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9' -> { sb.append(ch); foundAnyNumber = true }
',' -> if (foundAnyNumber) sb.append(ch) else error(si, "range quantifier is missing lower bound")
'}' -> {
sb.append(ch)
complete = true
}
null -> {}
else -> error(si, "invalid character '$ch'")
}
} while (ch != null && !complete)

if (!complete) {
error(si, "range quantifier missing '}'")
}
}
}

if (sb.length > initialLength && ch != null) {
ch = si.peek()
when (ch) {
'?' -> error(si, "invalid character '$ch'")
'+' -> error(si, "invalid character '$ch'")
}
}
}
private fun error(si: StringIterator, message: String): Unit =
throw InvalidSchemaException("$message in regex '$si' at offset ${si.currentIndex()}")

private class StringIterator(private val s: String) {
private var index = -1
val length = s.length

fun next(): Char? {
index += 1
return get(index)
}

fun peek() = get(index + 1)

private fun get(i: Int): Char? {
if (i < length) {
return s[i]
}
return null
}

fun currentIndex() = index

override fun toString() = s
}
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