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| 1 | +/* |
| 2 | + * Copyright 2017-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. |
| 3 | + */ |
| 4 | + |
| 5 | +package kotlinx.serialization.properties |
| 6 | + |
| 7 | +import kotlinx.serialization.* |
| 8 | +import kotlinx.serialization.descriptors.* |
| 9 | +import kotlinx.serialization.encoding.* |
| 10 | +import kotlinx.serialization.internal.* |
| 11 | +import kotlinx.serialization.modules.* |
| 12 | + |
| 13 | +/** |
| 14 | + * Transforms a [Serializable] class' properties into a single flat [String] representing the class data |
| 15 | + * in the properties format. |
| 16 | + * |
| 17 | + * If the given class has non-primitive property `d` of arbitrary type `D`, `D` values are inserted |
| 18 | + * into the same map; keys for such values are prefixed with string `d.`: |
| 19 | + * |
| 20 | + * ``` |
| 21 | + * @Serializable |
| 22 | + * class Data(val property1: String) |
| 23 | + * |
| 24 | + * @Serializable |
| 25 | + * class DataHolder(val data: Data, val property2: String) |
| 26 | + * |
| 27 | + * val string = StringProperties.encodeToString(properties) |
| 28 | + * // string contents will be the following: |
| 29 | + * """ |
| 30 | + * property2 = value2 |
| 31 | + * data.property1 = value1 |
| 32 | + * """ |
| 33 | + * ``` |
| 34 | + * |
| 35 | + * If the given class has a [List] property `l`, each value from the list |
| 36 | + * would be prefixed with `l.N.`, where N is an index for a particular value. |
| 37 | + * [Map] is treated as a `[key,value,...]` list. |
| 38 | +
|
| 39 | + * Conversely, this class can convert a properties string into a [Serializable] class instance. |
| 40 | + * ``` |
| 41 | + * @Serializable |
| 42 | + * class Data(val property1: String) |
| 43 | + * |
| 44 | + * @Serializable |
| 45 | + * class DataHolder(val data: Data, val property2: String) |
| 46 | + * |
| 47 | + * val string = """ |
| 48 | + * property2 = value2 |
| 49 | + * data.property1 = value1 |
| 50 | + * """ |
| 51 | + * val data = StringProperties.decodeToString(string, DataHolder.serializer()) |
| 52 | + * // data contents will be the following: |
| 53 | + * // DataHolder(data = Data(property1 = "value1"), property2 = "value2") |
| 54 | + * ``` |
| 55 | + * |
| 56 | + * @param conf A [PropertiesConf] which contain configuration for customising the output string. |
| 57 | + */ |
| 58 | +@ExperimentalSerializationApi |
| 59 | +@Suppress("UNUSED_PARAMETER") |
| 60 | +public sealed class StringProperties( |
| 61 | + private val conf: PropertiesConf, |
| 62 | + private val properties: Properties = Properties(conf.serializersModule), |
| 63 | +) : SerialFormat by properties, StringFormat { |
| 64 | + |
| 65 | + /** |
| 66 | + * Encodes properties from the given [value] to a properties String using the given [serializer]. |
| 67 | + * `null` values are omitted from the output. |
| 68 | + */ |
| 69 | + @ExperimentalSerializationApi |
| 70 | + public override fun <T> encodeToString(serializer: SerializationStrategy<T>, value: T): String { |
| 71 | + val map = properties.encodeToMap(serializer, value) |
| 72 | + val builder = StringBuilder() |
| 73 | + for ((k, v) in map) { |
| 74 | + builder.append(k) |
| 75 | + repeat(conf.spacesBeforeSeparator) { |
| 76 | + builder.append(' ') |
| 77 | + } |
| 78 | + builder.append(conf.keyValueSeparator.char()) |
| 79 | + repeat(conf.spacesAfterSeparator) { |
| 80 | + builder.append(' ') |
| 81 | + } |
| 82 | + builder.append(v) |
| 83 | + builder.append(conf.lineSeparator.chars()) |
| 84 | + } |
| 85 | + return builder.toString() |
| 86 | + } |
| 87 | + |
| 88 | + /** |
| 89 | + * Decodes properties from the given [string] to a value of type [T] using the given [deserializer]. |
| 90 | + * [String] values are converted to respective primitive types using default conversion methods. |
| 91 | + * [T] may contain properties of nullable types; they will be filled by non-null values from the [map], if present. |
| 92 | + */ |
| 93 | + public override fun <T> decodeFromString(deserializer: DeserializationStrategy<T>, string: String): T { |
| 94 | + val result = mutableMapOf<String, String>() |
| 95 | + for (line in string.logicalLines()) { |
| 96 | + val parsedLine = line.unescaped() |
| 97 | + var keyEnd = parsedLine.length |
| 98 | + for (i in parsedLine.indices) { |
| 99 | + if (parsedLine[i] in separators) { |
| 100 | + keyEnd = i |
| 101 | + break |
| 102 | + } |
| 103 | + } |
| 104 | + |
| 105 | + var valueBegin = parsedLine.length |
| 106 | + var separatorFound = false |
| 107 | + for (i in keyEnd..parsedLine.lastIndex) { |
| 108 | + if (separatorFound && parsedLine[i] != ' ') { |
| 109 | + valueBegin = i |
| 110 | + break |
| 111 | + } |
| 112 | + if (parsedLine[i] in nonBlankSeparators) { |
| 113 | + separatorFound = true |
| 114 | + } |
| 115 | + if (parsedLine[i] !in separators) { |
| 116 | + valueBegin = i |
| 117 | + break |
| 118 | + } |
| 119 | + } |
| 120 | + |
| 121 | + result[parsedLine.substring(0, keyEnd)] = parsedLine.substring(valueBegin) |
| 122 | + } |
| 123 | + return properties.decodeFromStringMap(deserializer, result) |
| 124 | + } |
| 125 | + |
| 126 | + /** |
| 127 | + * A [Properties] instance that can be used as default and does not have any [SerializersModule] installed. |
| 128 | + */ |
| 129 | + @ExperimentalSerializationApi |
| 130 | + public companion object Default : StringProperties(PropertiesConf()) |
| 131 | +} |
| 132 | + |
| 133 | +@OptIn(ExperimentalSerializationApi::class) |
| 134 | +private class StringPropertiesImpl(conf: PropertiesConf) : StringProperties(conf) |
| 135 | + |
| 136 | +/** |
| 137 | + * Creates an instance of [StringProperties] with a given [builderAction]. |
| 138 | + * TODO: doc |
| 139 | + */ |
| 140 | +@ExperimentalSerializationApi |
| 141 | +public fun StringProperties(builderAction: StringPropertiesBuilder.() -> Unit = {}): StringProperties { |
| 142 | + val builder = StringPropertiesBuilder(PropertiesConf()) |
| 143 | + builder.builderAction() |
| 144 | + return StringPropertiesImpl(builder.build()) |
| 145 | +} |
| 146 | + |
| 147 | +/** |
| 148 | + * Encodes properties from given [value] to a string using serializer for reified type [T] and returns this string. |
| 149 | + * Converts all primitive types to [String] using [toString] method. |
| 150 | + * `null` values are omitted from the output. |
| 151 | + */ |
| 152 | +@ExperimentalSerializationApi |
| 153 | +public inline fun <reified T> StringProperties.encodeToString(value: T): String = |
| 154 | + encodeToString(serializersModule.serializer(), value) |
| 155 | + |
| 156 | +/** |
| 157 | + * Decodes properties from given [propertiesString], assigns them to an object using serializer for reified type [T] and returns this object. |
| 158 | + * [String] values are converted to respective primitive types using default conversion methods. |
| 159 | + * [T] may contain properties of nullable types; they will be filled by non-null values from the [map], if present. |
| 160 | + */ |
| 161 | +@ExperimentalSerializationApi |
| 162 | +public inline fun <reified T> StringProperties.decodeFromString(propertiesString: String): T = |
| 163 | + decodeFromString(serializersModule.serializer(), propertiesString) |
| 164 | + |
| 165 | +/** |
| 166 | + * Builder of the [StringProperties] instance provided by `StringProperties { ... }` factory function. |
| 167 | + */ |
| 168 | +@ExperimentalSerializationApi |
| 169 | +public class StringPropertiesBuilder internal constructor(from: PropertiesConf) { |
| 170 | + |
| 171 | + /** |
| 172 | + * A [LineSeparator] to be used for separating lines when encoding to a string. |
| 173 | + * Default value is [LineSeparator.LF]. |
| 174 | + */ |
| 175 | + public var lineSeparator: LineSeparator = from.lineSeparator |
| 176 | + |
| 177 | + /** |
| 178 | + * A [KeyValueSeparator] to be used for separating keys and values when encoding to a string. |
| 179 | + * Default value is [KeyValueSeparator.EQUALS]. |
| 180 | + */ |
| 181 | + public var keyValueSeparator: KeyValueSeparator = from.keyValueSeparator |
| 182 | + |
| 183 | + /** |
| 184 | + * A number of spaces to be inserted before the [keyValueSeparator] when encoding to a string. |
| 185 | + * Default value is `0`. |
| 186 | + */ |
| 187 | + public var spacesBeforeSeparator: Int = from.spacesBeforeSeparator |
| 188 | + |
| 189 | + /** |
| 190 | + * A number of spaces to be inserted after the [keyValueSeparator] when encoding to a string. |
| 191 | + * Default value is `0`. |
| 192 | + */ |
| 193 | + public var spacesAfterSeparator: Int = from.spacesAfterSeparator |
| 194 | + |
| 195 | + /** |
| 196 | + * A [SerializersModule] to be used for encoding and decoding. |
| 197 | + * Default value is [EmptySerializersModule]. |
| 198 | + */ |
| 199 | + public var module: SerializersModule = from.serializersModule |
| 200 | + |
| 201 | + internal fun build(): PropertiesConf { |
| 202 | + return PropertiesConf( |
| 203 | + lineSeparator, |
| 204 | + keyValueSeparator, |
| 205 | + spacesBeforeSeparator, |
| 206 | + spacesAfterSeparator, |
| 207 | + module |
| 208 | + ) |
| 209 | + } |
| 210 | +} |
| 211 | + |
| 212 | +@ExperimentalSerializationApi |
| 213 | +internal data class PropertiesConf( |
| 214 | + val lineSeparator: LineSeparator = LineSeparator.LF, |
| 215 | + val keyValueSeparator: KeyValueSeparator = KeyValueSeparator.EQUALS, |
| 216 | + val spacesBeforeSeparator: Int = 0, |
| 217 | + val spacesAfterSeparator: Int = 0, |
| 218 | + val serializersModule: SerializersModule = EmptySerializersModule() |
| 219 | +) |
| 220 | + |
| 221 | +@ExperimentalSerializationApi |
| 222 | +public enum class LineSeparator(private val s: String) { |
| 223 | + LF("\n"), |
| 224 | + CR("\r"), |
| 225 | + CRLF("\r\n"); |
| 226 | + |
| 227 | + public fun chars(): CharArray { |
| 228 | + return s.toCharArray() |
| 229 | + } |
| 230 | +} |
| 231 | + |
| 232 | +@ExperimentalSerializationApi |
| 233 | +public enum class KeyValueSeparator(private val c: Char) { |
| 234 | + EQUALS('='), |
| 235 | + COLON(':'); |
| 236 | + |
| 237 | + public fun char(): Char = c |
| 238 | +} |
| 239 | + |
| 240 | +private val nonBlankSeparators = setOf('=', ':') |
| 241 | +private val separators = nonBlankSeparators + ' ' |
| 242 | +private val wellKnownEscapeChars = mapOf( |
| 243 | + '\\' to '\\', |
| 244 | + 'n' to '\n', |
| 245 | + 'r' to '\r', |
| 246 | + 't' to '\t' |
| 247 | +) |
| 248 | + |
| 249 | +private fun String.unescaped(): String { |
| 250 | + val sb = StringBuilder(this.length) |
| 251 | + var i = 0 |
| 252 | + while (i < this.length) { |
| 253 | + if (i < this.length - 1 && this[i] == '\\') { |
| 254 | + if (this[i + 1] in wellKnownEscapeChars) { |
| 255 | + sb.append(wellKnownEscapeChars[this[i + 1]]) |
| 256 | + i += 2 |
| 257 | + } else { |
| 258 | + i++ |
| 259 | + } |
| 260 | + } else { |
| 261 | + sb.append(this[i]) |
| 262 | + i++ |
| 263 | + } |
| 264 | + } |
| 265 | + return sb.toString() |
| 266 | +} |
| 267 | + |
| 268 | +private fun String.logicalLines(): List<String> { |
| 269 | + val commentFilter = "[ \\t\\f]*[#!].*".toRegex() |
| 270 | + val lines = lines() |
| 271 | + .filterNot { it.isBlank() || commentFilter.matches(it) } |
| 272 | + .toMutableList() |
| 273 | + val logicalLines = mutableListOf<String>() |
| 274 | + |
| 275 | + var currentLine = "" |
| 276 | + for (line in lines) { |
| 277 | + val trimmedLine = line.trimStart() |
| 278 | + if (trimmedLine.endsWith("\\")) { |
| 279 | + currentLine += trimmedLine.dropLast(1) |
| 280 | + } else { |
| 281 | + currentLine += trimmedLine |
| 282 | + logicalLines.add(currentLine) |
| 283 | + currentLine = "" |
| 284 | + } |
| 285 | + } |
| 286 | + if (currentLine.isNotBlank()) { |
| 287 | + logicalLines.add(currentLine) |
| 288 | + } |
| 289 | + |
| 290 | + return logicalLines |
| 291 | +} |
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