Kotlin conversion: Passphrase

pgpainless-core/src/main/java/org/pgpainless/util/Passphrase.java

@@ -1,168 +0,0 @@
-// SPDX-FileCopyrightText: 2018 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.util;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-import java.util.Arrays;
-
-public class Passphrase {
-
-    public final Object lock = new Object();
-
-    private final char[] chars;
-    private boolean valid = true;
-
-    /**
-     * Passphrase for keys etc.
-     *
-     * @param chars may be null for empty passwords.
-     */
-    public Passphrase(@Nullable char[] chars) {
-        if (chars == null) {
-            this.chars = null;
-        } else {
-            char[] trimmed = removeTrailingAndLeadingWhitespace(chars);
-            if (trimmed.length == 0) {
-                this.chars = null;
-            } else {
-                this.chars = trimmed;
-            }
-        }
-    }
-
-    /**
-     * Return a copy of the passed in char array, with leading and trailing whitespace characters removed.
-     *
-     * @param chars char array
-     * @return copy of char array with leading and trailing whitespace characters removed
-     */
-    private static char[] removeTrailingAndLeadingWhitespace(char[] chars) {
-        int i = 0;
-        while (i < chars.length && isWhitespace(chars[i])) {
-            i++;
-        }
-        int j = chars.length - 1;
-        while (j >= i && isWhitespace(chars[j])) {
-            j--;
-        }
-
-        char[] trimmed = new char[chars.length - i - (chars.length - 1 - j)];
-        System.arraycopy(chars, i, trimmed, 0, trimmed.length);
-
-        return trimmed;
-    }
-
-    /**
-     * Return true, if the passed in char is a whitespace symbol (space, newline, tab).
-     *
-     * @param xar char
-     * @return true if whitespace
-     */
-    private static boolean isWhitespace(char xar) {
-        return xar == ' ' || xar == '\n' || xar == '\t';
-    }
-
-    /**
-     * Create a {@link Passphrase} from a {@link String}.
-     *
-     * @param password password
-     * @return passphrase
-     */
-    public static Passphrase fromPassword(@Nonnull String password) {
-        return new Passphrase(password.toCharArray());
-    }
-
-    /**
-     * Overwrite the char array with spaces and mark the {@link Passphrase} as invalidated.
-     */
-    public void clear() {
-        synchronized (lock) {
-            if (chars != null) {
-                Arrays.fill(chars, ' ');
-            }
-            valid = false;
-        }
-    }
-
-    /**
-     * Return a copy of the underlying char array.
-     * A return value of {@code null} represents no password.
-     *
-     * @return passphrase chars.
-     *
-     * @throws IllegalStateException in case the password has been cleared at this point.
-     */
-    public @Nullable char[] getChars() {
-        synchronized (lock) {
-            if (!valid) {
-                throw new IllegalStateException("Passphrase has been cleared.");
-            }
-
-            if (chars == null) {
-                return null;
-            }
-
-            char[] copy = new char[chars.length];
-            System.arraycopy(chars, 0, copy, 0, chars.length);
-            return copy;
-        }
-    }
-
-    /**
-     * Return true if the passphrase has not yet been cleared.
-     *
-     * @return valid
-     */
-    public boolean isValid() {
-        synchronized (lock) {
-            return valid;
-        }
-    }
-
-    /**
-     * Return true if the passphrase represents no password.
-     *
-     * @return empty
-     */
-    public boolean isEmpty() {
-        synchronized (lock) {
-            return valid && chars == null;
-        }
-    }
-
-    /**
-     * Represents a {@link Passphrase} instance that represents no password.
-     *
-     * @return empty passphrase
-     */
-    public static Passphrase emptyPassphrase() {
-        return new Passphrase(null);
-    }
-
-    @Override
-    public int hashCode() {
-        if (getChars() == null) {
-            return 0;
-        }
-        return new String(getChars()).hashCode();
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-        if (obj == null) {
-            return false;
-        }
-        if (this == obj) {
-            return true;
-        }
-        if (!(obj instanceof Passphrase)) {
-            return false;
-        }
-        Passphrase other = (Passphrase) obj;
-        return (getChars() == null && other.getChars() == null) ||
-                org.bouncycastle.util.Arrays.constantTimeAreEqual(getChars(), other.getChars());
-    }
-}

pgpainless-core/src/main/kotlin/org/pgpainless/util/Passphrase.kt

@@ -0,0 +1,105 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.util
+
+import org.bouncycastle.util.Arrays
+
+/**
+ * Passphrase for keys or messages.
+ *
+ * @param chars may be null for empty passwords.
+ */
+class Passphrase(
+        chars: CharArray?
+) {
+    private val lock = Any()
+    private var valid = true
+    private val chars: CharArray?
+
+    init {
+        this.chars = trimWhitespace(chars)
+    }
+
+    /**
+     * Return a copy of the underlying char array.
+     * A return value of null represents an empty password.
+     *
+     * @return passphrase chars.
+     *
+     * @throws IllegalStateException in case the password has been cleared at this point.
+     */
+    fun getChars(): CharArray? = synchronized(lock) {
+        check(valid) { "Passphrase has been cleared." }
+        chars?.copyOf()
+    }
+
+    /**
+     * Return true if the passphrase has not yet been cleared.
+     *
+     * @return valid
+     */
+    val isValid: Boolean
+        get() = synchronized(lock) { valid }
+
+    /**
+     * Return true if the passphrase represents no password.
+     *
+     * @return empty
+     */
+    val isEmpty: Boolean
+        get() = synchronized(lock) { valid && chars == null }
+
+    /**
+     * Overwrite the char array with spaces and mark the [Passphrase] as invalidated.
+     */
+    fun clear() = synchronized(lock) {
+        chars?.fill(' ')
+        valid = false
+    }
+
+    override fun equals(other: Any?): Boolean {
+        return if (other == null)
+            false
+        else if (this === other)
+            true
+        else if (other !is Passphrase)
+            false
+        else
+            getChars() == null && other.getChars() == null || Arrays.constantTimeAreEqual(getChars(), other.getChars())
+    }
+
+    override fun hashCode(): Int = getChars()?.let { String(it) }.hashCode()
+
+    companion object {
+
+        /**
+         * Create a [Passphrase] from a [CharSequence].
+         *
+         * @param password password
+         * @return passphrase
+         */
+        @JvmStatic
+        fun fromPassword(password: CharSequence) = Passphrase(password.toString().toCharArray())
+
+        @JvmStatic
+        fun emptyPassphrase() = Passphrase(null)
+
+        /**
+         * Return a copy of the passed in char array, with leading and trailing whitespace characters removed.
+         * If the passed in char array is null, return null.
+         * If the resulting char array is empty, return null as well.
+         *
+         * @param chars char array
+         * @return copy of char array with leading and trailing whitespace characters removed
+         */
+        @JvmStatic
+        private fun trimWhitespace(chars: CharArray?): CharArray? {
+            return chars?.dropWhile { it.isWhitespace() }
+                    ?.dropLastWhile { it.isWhitespace() }
+                    ?.toCharArray()
+                    ?.let { if (it.isEmpty()) null else it }
+        }
+    }
+}