Refactor randomized password generator into a separate module (#1663)

app/build.gradle.kts

@@ -79,6 +79,7 @@ dependencies {
   implementation(projects.formatCommon)
   implementation(projects.openpgpKtx)
   implementation(projects.passgen.diceware)
+  implementation(projects.passgen.random)
   implementation(libs.androidx.activity.ktx)
   implementation(libs.androidx.appcompat)
   implementation(libs.androidx.autofill)

app/src/main/java/dev/msfjarvis/aps/ui/dialogs/PasswordGeneratorDialogFragment.kt

@@ -14,6 +14,7 @@ import android.widget.EditText
 import android.widget.Toast
 import androidx.annotation.IdRes
 import androidx.appcompat.widget.AppCompatTextView
+import androidx.core.content.edit
 import androidx.core.os.bundleOf
 import androidx.fragment.app.DialogFragment
 import androidx.fragment.app.setFragmentResult
@@ -23,11 +24,12 @@ import com.github.michaelbull.result.runCatching
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import dev.msfjarvis.aps.R
 import dev.msfjarvis.aps.databinding.FragmentPwgenBinding
+import dev.msfjarvis.aps.passgen.random.MaxIterationsExceededException
+import dev.msfjarvis.aps.passgen.random.NoCharactersIncludedException
+import dev.msfjarvis.aps.passgen.random.PasswordGenerator
+import dev.msfjarvis.aps.passgen.random.PasswordLengthTooShortException
+import dev.msfjarvis.aps.passgen.random.PasswordOption
 import dev.msfjarvis.aps.ui.crypto.PasswordCreationActivity
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator.generate
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator.setPrefs
-import dev.msfjarvis.aps.util.pwgen.PasswordOption
 import dev.msfjarvis.aps.util.settings.PreferenceKeys
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.launchIn
@@ -96,10 +98,23 @@ class PasswordGeneratorDialogFragment : DialogFragment() {
   }
 
   private fun generate(passwordField: AppCompatTextView) {
-    setPreferences()
+    val passwordOptions = getSelectedOptions()
+    val passwordLength = getLength()
+    setPrefs(requireContext(), passwordOptions, passwordLength)
     passwordField.text =
-      runCatching { generate(requireContext().applicationContext) }.getOrElse { e ->
+      runCatching { PasswordGenerator.generate(passwordOptions, passwordLength) }.getOrElse {
-        Toast.makeText(requireActivity(), e.message, Toast.LENGTH_SHORT).show()
+        exception ->
+        val errorText =
+          when (exception) {
+            is MaxIterationsExceededException ->
+              requireContext().getString(R.string.pwgen_max_iterations_exceeded)
+            is NoCharactersIncludedException ->
+              requireContext().getString(R.string.pwgen_no_chars_error)
+            is PasswordLengthTooShortException ->
+              requireContext().getString(R.string.pwgen_length_too_short_error)
+            else -> requireContext().getString(R.string.pwgen_some_error_occurred)
+          }
+        Toast.makeText(requireActivity(), errorText, Toast.LENGTH_SHORT).show()
         ""
       }
   }
@@ -108,18 +123,34 @@ class PasswordGeneratorDialogFragment : DialogFragment() {
     return requireDialog().findViewById<CheckBox>(id).isChecked
   }
 
-  private fun setPreferences() {
+  private fun getSelectedOptions(): List<PasswordOption> {
-    val preferences =
+    return listOfNotNull(
-      listOfNotNull(
+      PasswordOption.NoDigits.takeIf { !isChecked(R.id.numerals) },
-        PasswordOption.NoDigits.takeIf { !isChecked(R.id.numerals) },
+      PasswordOption.AtLeastOneSymbol.takeIf { isChecked(R.id.symbols) },
-        PasswordOption.AtLeastOneSymbol.takeIf { isChecked(R.id.symbols) },
+      PasswordOption.NoUppercaseLetters.takeIf { !isChecked(R.id.uppercase) },
-        PasswordOption.NoUppercaseLetters.takeIf { !isChecked(R.id.uppercase) },
+      PasswordOption.NoAmbiguousCharacters.takeIf { !isChecked(R.id.ambiguous) },
-        PasswordOption.NoAmbiguousCharacters.takeIf { !isChecked(R.id.ambiguous) },
+      PasswordOption.FullyRandom.takeIf { !isChecked(R.id.pronounceable) },
-        PasswordOption.FullyRandom.takeIf { !isChecked(R.id.pronounceable) },
+      PasswordOption.NoLowercaseLetters.takeIf { !isChecked(R.id.lowercase) }
-        PasswordOption.NoLowercaseLetters.takeIf { !isChecked(R.id.lowercase) }
+    )
-      )
+  }
+
+  private fun getLength(): Int {
     val lengthText = requireDialog().findViewById<EditText>(R.id.lengthNumber).text.toString()
-    val length = lengthText.toIntOrNull()?.takeIf { it >= 0 } ?: PasswordGenerator.DEFAULT_LENGTH
+    return lengthText.toIntOrNull()?.takeIf { it >= 0 } ?: PasswordGenerator.DEFAULT_LENGTH
-    setPrefs(requireActivity().applicationContext, preferences, length)
+  }
+
+  /**
+   * Enables the [PasswordOption]s in [options] and sets [targetLength] as the length for generated
+   * passwords.
+   */
+  private fun setPrefs(ctx: Context, options: List<PasswordOption>, targetLength: Int): Boolean {
+    ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE).edit {
+      for (possibleOption in PasswordOption.values()) putBoolean(
+        possibleOption.key,
+        possibleOption in options
+      )
+      putInt("length", targetLength)
+    }
+    return true
   }
 }

app/src/main/res/values/strings.xml

@@ -391,5 +391,6 @@
   <string name="pgp_key_import_succeeded">Successfully imported PGP key</string>
   <string name="pgp_key_import_succeeded_message">The key ID of the imported key is given below, please review it for correctness:\n%1$s</string>
   <string name="pref_category_pgp_title">PGP settings</string>
+  <string name="pwgen_some_error_occurred">Some error occurred</string>
 
 </resources>

build-logic/kotlin-plugins/src/main/kotlin/com.github.android-password-store.binary-compatibility.gradle.kts

@@ -15,5 +15,6 @@ apiValidation {
       "crypto-pgpainless",
       "format-common",
       "diceware",
+      "random",
     )
 }

passgen/random/.gitignore

@@ -0,0 +1 @@
+/build

passgen/random/build.gradle.kts

@@ -0,0 +1,4 @@
+plugins {
+  kotlin("jvm")
+  id("com.github.android-password-store.kotlin-library")
+}

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/PasswordGenerator.kt

@@ -2,56 +2,28 @@
  * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
  * SPDX-License-Identifier: GPL-3.0-only
  */
-package dev.msfjarvis.aps.util.pwgen
+package dev.msfjarvis.aps.passgen.random
 
-import android.content.Context
+import dev.msfjarvis.aps.passgen.random.util.clearFlag
-import androidx.core.content.edit
+import dev.msfjarvis.aps.passgen.random.util.hasFlag
-import dev.msfjarvis.aps.R
-import dev.msfjarvis.aps.util.extensions.clearFlag
-import dev.msfjarvis.aps.util.extensions.hasFlag
-import dev.msfjarvis.aps.util.settings.PreferenceKeys
 
-enum class PasswordOption(val key: String) {
+public object PasswordGenerator {
-  NoDigits("0"),
-  NoUppercaseLetters("A"),
-  NoAmbiguousCharacters("B"),
-  FullyRandom("s"),
-  AtLeastOneSymbol("y"),
-  NoLowercaseLetters("L")
-}
 
-object PasswordGenerator {
+  public const val DEFAULT_LENGTH: Int = 16
 
-  const val DEFAULT_LENGTH = 16
+  internal const val DIGITS = 0x0001
+  internal const val UPPERS = 0x0002
+  internal const val SYMBOLS = 0x0004
+  internal const val NO_AMBIGUOUS = 0x0008
+  internal const val LOWERS = 0x0020
 
-  const val DIGITS = 0x0001
+  internal const val DIGITS_STR = "0123456789"
-  const val UPPERS = 0x0002
+  internal const val UPPERS_STR = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-  const val SYMBOLS = 0x0004
+  internal const val LOWERS_STR = "abcdefghijklmnopqrstuvwxyz"
-  const val NO_AMBIGUOUS = 0x0008
+  internal const val SYMBOLS_STR = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
-  const val LOWERS = 0x0020
+  internal const val AMBIGUOUS_STR = "B8G6I1l0OQDS5Z2"
 
-  const val DIGITS_STR = "0123456789"
+  internal fun isValidPassword(password: String, pwFlags: Int): Boolean {
-  const val UPPERS_STR = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-  const val LOWERS_STR = "abcdefghijklmnopqrstuvwxyz"
-  const val SYMBOLS_STR = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
-  const val AMBIGUOUS_STR = "B8G6I1l0OQDS5Z2"
-
-  /**
-   * Enables the [PasswordOption] s in [options] and sets [targetLength] as the length for generated
-   * passwords.
-   */
-  fun setPrefs(ctx: Context, options: List<PasswordOption>, targetLength: Int): Boolean {
-    ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE).edit {
-      for (possibleOption in PasswordOption.values()) putBoolean(
-        possibleOption.key,
-        possibleOption in options
-      )
-      putInt("length", targetLength)
-    }
-    return true
-  }
-
-  fun isValidPassword(password: String, pwFlags: Int): Boolean {
     if (pwFlags hasFlag DIGITS && password.none { it in DIGITS_STR }) return false
     if (pwFlags hasFlag UPPERS && password.none { it in UPPERS_STR }) return false
     if (pwFlags hasFlag LOWERS && password.none { it in LOWERS_STR }) return false
@@ -60,17 +32,15 @@ object PasswordGenerator {
     return true
   }
 
-  /** Generates a password using the preferences set by [setPrefs]. */
+  /** Generates a password using the given [passwordOptions] and [length]. */
   @Throws(PasswordGeneratorException::class)
-  fun generate(ctx: Context): String {
+  public fun generate(passwordOptions: List<PasswordOption>, length: Int = DEFAULT_LENGTH): String {
-    val prefs = ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE)
     var numCharacterCategories = 0
-
     var phonemes = true
     var pwgenFlags = DIGITS or UPPERS or LOWERS
 
     for (option in PasswordOption.values()) {
-      if (prefs.getBoolean(option.key, false)) {
+      if (option in passwordOptions) {
         when (option) {
           PasswordOption.NoDigits -> pwgenFlags = pwgenFlags.clearFlag(DIGITS)
           PasswordOption.NoUppercaseLetters -> pwgenFlags = pwgenFlags.clearFlag(UPPERS)
@@ -98,14 +68,11 @@ object PasswordGenerator {
       }
     }
 
-    val length = prefs.getInt(PreferenceKeys.LENGTH, DEFAULT_LENGTH)
     if (pwgenFlags.clearFlag(NO_AMBIGUOUS) == 0) {
-      throw PasswordGeneratorException(ctx.resources.getString(R.string.pwgen_no_chars_error))
+      throw NoCharactersIncludedException()
     }
     if (length < numCharacterCategories) {
-      throw PasswordGeneratorException(
+      throw PasswordLengthTooShortException()
-        ctx.resources.getString(R.string.pwgen_length_too_short_error)
-      )
     }
     if (!(pwgenFlags hasFlag UPPERS) && !(pwgenFlags hasFlag LOWERS)) {
       phonemes = false
@@ -120,10 +87,7 @@ object PasswordGenerator {
     var password: String?
     var iterations = 0
     do {
-      if (iterations++ > 1000)
+      if (iterations++ > 1000) throw MaxIterationsExceededException()
-        throw PasswordGeneratorException(
-          ctx.resources.getString(R.string.pwgen_max_iterations_exceeded)
-        )
       password =
         if (phonemes) {
           RandomPhonemesGenerator.generate(length, pwgenFlags)
@@ -133,6 +97,4 @@ object PasswordGenerator {
     } while (password == null)
     return password
   }
-
-  class PasswordGeneratorException(string: String) : Exception(string)
 }

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/PasswordGeneratorException.kt

@@ -0,0 +1,10 @@
+package dev.msfjarvis.aps.passgen.random
+
+public sealed class PasswordGeneratorException(message: String? = null, cause: Throwable? = null) :
+  Throwable(message, cause)
+
+public class MaxIterationsExceededException : PasswordGeneratorException()
+
+public class NoCharactersIncludedException : PasswordGeneratorException()
+
+public class PasswordLengthTooShortException : PasswordGeneratorException()

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/PasswordOption.kt

@@ -0,0 +1,10 @@
+package dev.msfjarvis.aps.passgen.random
+
+public enum class PasswordOption(public val key: String) {
+  NoDigits("0"),
+  NoUppercaseLetters("A"),
+  NoAmbiguousCharacters("B"),
+  FullyRandom("s"),
+  AtLeastOneSymbol("y"),
+  NoLowercaseLetters("L")
+}

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/RandomNumberGenerator.kt

@@ -2,30 +2,30 @@
  * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
  * SPDX-License-Identifier: GPL-3.0-only
  */
-package dev.msfjarvis.aps.util.pwgen
+package dev.msfjarvis.aps.passgen.random
 
 import java.security.SecureRandom
 
 private val secureRandom = SecureRandom()
 
 /** Returns a number between 0 (inclusive) and [exclusiveBound](exclusive). */
-fun secureRandomNumber(exclusiveBound: Int) = secureRandom.nextInt(exclusiveBound)
+internal fun secureRandomNumber(exclusiveBound: Int) = secureRandom.nextInt(exclusiveBound)
 
 /** Returns `true` and `false` with probablity 50% each. */
-fun secureRandomBoolean() = secureRandom.nextBoolean()
+internal fun secureRandomBoolean() = secureRandom.nextBoolean()
 
 /**
  * Returns `true` with probability [percentTrue]% and `false` with probability `(100 - [percentTrue]
  * )`%.
  */
-fun secureRandomBiasedBoolean(percentTrue: Int): Boolean {
+internal fun secureRandomBiasedBoolean(percentTrue: Int): Boolean {
   require(1 <= percentTrue) { "Probability for returning `true` must be at least 1%" }
   require(percentTrue <= 99) { "Probability for returning `true` must be at most 99%" }
   return secureRandomNumber(100) < percentTrue
 }
 
-fun <T> Array<T>.secureRandomElement() = this[secureRandomNumber(size)]
+internal fun <T> Array<T>.secureRandomElement() = this[secureRandomNumber(size)]
 
-fun <T> List<T>.secureRandomElement() = this[secureRandomNumber(size)]
+internal fun <T> List<T>.secureRandomElement() = this[secureRandomNumber(size)]
 
-fun String.secureRandomCharacter() = this[secureRandomNumber(length)]
+internal fun String.secureRandomCharacter() = this[secureRandomNumber(length)]

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/RandomPasswordGenerator.kt

@@ -2,11 +2,11 @@
  * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
  * SPDX-License-Identifier: GPL-3.0-only
  */
-package dev.msfjarvis.aps.util.pwgen
+package dev.msfjarvis.aps.passgen.random
 
-import dev.msfjarvis.aps.util.extensions.hasFlag
+import dev.msfjarvis.aps.passgen.random.util.hasFlag
 
-object RandomPasswordGenerator {
+internal object RandomPasswordGenerator {
 
   /**
    * Generates a random password of length [targetLength], taking the following flags in [pwFlags]

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/RandomPhonemesGenerator.kt

@@ -2,12 +2,12 @@
  * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
  * SPDX-License-Identifier: GPL-3.0-only
  */
-package dev.msfjarvis.aps.util.pwgen
+package dev.msfjarvis.aps.passgen.random
 
-import dev.msfjarvis.aps.util.extensions.hasFlag
+import dev.msfjarvis.aps.passgen.random.util.hasFlag
 import java.util.Locale
 
-object RandomPhonemesGenerator {
+internal object RandomPhonemesGenerator {
 
   private const val CONSONANT = 0x0001
   private const val VOWEL = 0x0002

passgen/random/src/main/kotlin/dev/msfjarvis/aps/passgen/random/util/Extensions.kt

@@ -0,0 +1,11 @@
+package dev.msfjarvis.aps.passgen.random.util
+
+/** Clears the given [flag] from the value of this [Int] */
+internal infix fun Int.clearFlag(flag: Int): Int {
+  return this and flag.inv()
+}
+
+/** Checks if this [Int] contains the given [flag] */
+internal infix fun Int.hasFlag(flag: Int): Boolean {
+  return this and flag == flag
+}

settings.gradle.kts

@@ -53,3 +53,5 @@ include("format-common")
 include("openpgp-ktx")
 
 include("passgen:diceware")
+
+include(":passgen:random")