chore: create backup module

This commit introduces a new cross-platform backup module to the project with support for iOS, Web, and Android. Additionally, it enables JavaScript multiplatform support in existing `kalium/network-model` and `kalium/data` projects.

backup/README.md

@@ -0,0 +1,57 @@
+# Cross-platform Backup
+
+This module implements the Wire Cross-platform Backup solution.
+Its purpose is to create a common implementation to be used by iOS, Web, and Android.
+
+## Capabilities
+
+> [!TIP]
+> The backup blob/file will be referred in this document as **backup artifact**, or simply 
+> **artifact**.
+> The clients (iOS, Web, and Android) will be referred as **callers**.
+
+### Creation of backup artifact
+
+The library should be able to transform data like messages, conversations, users into an artifact,
+_i.e._ create a backup file.
+
+### Restoration of original data
+
+It should also be able to revert this process, _i.e._ read a backup artifact and understand all of
+its contents, allowing the caller to get access to the original data.
+
+### Optional Encryption
+
+The artifact may _(or may not)_ be Encrypted. Clients using this library can provide an optional
+passphrase to encrypt and decrypt the artifact.
+
+### Optional UserID verification
+
+When creating an artifact, callers need to provide a qualified user ID. This qualified user ID will
+be stored within the artifact.
+When restoring the original data, the library _can_ compare the user ID in the artifact with a user
+ID provided by the caller. This may not be wanted in all features, _e.g._ in case of chat history
+sharing across different users.
+
+### Peak into artifact
+
+Clients can ask the library if a piece of data is an actual cross-platform artifact.
+The library should respond yes/no, and provide more details in case of a positive answer: is it
+encrypted? Was it created by the same user that is restoring the artifact?
+
+--------
+
+# Development
+
+Using Kotlin Multiplatform, it should at least be available for iOS, JS (with TypeScript types),
+Android, and JVM.
+
+### Building
+
+Before we can automate the deployment of this library, we can manually generate and send library
+artifacts (not backup artifacts) using the following Gradle tasks:
+
+- iOS: `./gradlew :backup:assembleBackupDebugXCFramework`
+- Web: `./gradlew :backup:jsBrowserDevelopmentLibraryDistribution`
+
+**Output:** the results will be in `backup/build` directory. iOS needs the whole `backup.xcframework` directory, Web/JS needs the whole directory that contains `package.json`

backup/build.gradle.kts

@@ -0,0 +1,115 @@
+import org.jetbrains.kotlin.gradle.plugin.mpp.apple.XCFramework
+
+/*
+ * Wire
+ * Copyright (C) 2024 Wire Swiss GmbH
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see http://www.gnu.org/licenses/.
+ */
+plugins {
+    id(libs.plugins.android.library.get().pluginId)
+    id(libs.plugins.kotlin.multiplatform.get().pluginId)
+    alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.ksp)
+    id(libs.plugins.kalium.library.get().pluginId)
+}
+
+kaliumLibrary {
+    multiplatform { enableJs.set(true) }
+}
+
+@Suppress("UnusedPrivateProperty")
+kotlin {
+    val xcf = XCFramework()
+    val appleTargets = listOf(iosX64(), iosArm64(), iosSimulatorArm64(), macosArm64(), macosX64())
+    appleTargets.forEach {
+        it.binaries.framework {
+            baseName = "backup"
+            xcf.add(this)
+        }
+    }
+    js {
+        browser()
+        binaries.library()
+        generateTypeScriptDefinitions()
+    }
+    sourceSets {
+        val commonMain by getting {
+            dependencies {
+                implementation(project(":data"))
+                implementation(project(":protobuf"))
+                implementation(libs.pbandk.runtime.common)
+
+                implementation(libs.coroutines.core)
+                implementation(libs.ktxDateTime)
+                implementation(libs.ktxSerialization)
+
+                implementation(libs.okio.core)
+
+                // Libsodium
+                implementation(libs.libsodiumBindingsMP)
+            }
+        }
+        val commonTest by getting {
+            dependencies {
+                implementation(libs.coroutines.test)
+                implementation(libs.okio.test)
+            }
+        }
+
+        val nonJsMain by creating {
+            dependsOn(commonMain)
+        }
+        val nonJsTest by creating {
+            dependsOn(commonTest)
+        }
+        val androidMain by getting {
+            dependsOn(nonJsMain)
+        }
+        val jvmMain by getting {
+            dependsOn(nonJsMain)
+        }
+
+        val iosX64Main by getting {
+            dependsOn(nonJsMain)
+            dependencies {
+                implementation(libs.pbandk.runtime.iosX64)
+            }
+        }
+        val iosArm64Main by getting {
+            dependsOn(nonJsMain)
+            dependencies {
+                implementation(libs.pbandk.runtime.iosArm64)
+            }
+        }
+        val iosSimulatorArm64Main by getting {
+            dependsOn(nonJsMain)
+            dependencies {
+                implementation(libs.pbandk.runtime.iosSimulatorArm64)
+            }
+        }
+        val macosX64Main by getting {
+            dependsOn(nonJsMain)
+            dependencies {
+                implementation(libs.pbandk.runtime.macX64)
+            }
+        }
+        val macosArm64Main by getting {
+            dependsOn(nonJsMain)
+            dependencies {
+                implementation(libs.pbandk.runtime.macArm64)
+            }
+        }
+    }
+}

data/build.gradle.kts

@@ -24,13 +24,12 @@ plugins {
 }
 
 kaliumLibrary {
-    multiplatform {
-        enableJs.set(false)
-    }
+    multiplatform { }
 }
+
+@Suppress("UnusedPrivateProperty")
 kotlin {
     sourceSets {
-        @Suppress("UnusedPrivateProperty")
         val commonMain by getting {
             dependencies {
                 implementation(project(":network-model"))

network-model/build.gradle.kts

@@ -25,7 +25,7 @@ plugins {
 
 kaliumLibrary {
     multiplatform {
-        enableJs.set(false)
+        enableJs.set(true)
     }
 }