Adds SQLCipher Custom Fork documentation

Documentation/CustomSQLCipherBuilds.md

@@ -0,0 +1,86 @@
+Custom SQLCipher Builds
+=====================
+
+To use the official SQLCipher.swift package in conjunction with GRDB, you can use the official [fork of GRDB w/SQLCipher](https://github.com/sqlcipher/GRDB.swift). This fork is maintained by the SQLCipher team in collaboration with GRDB and is the recommended fork to use to enable SQLCipher encryption for GRDB.
+
+If you have requirements that the official SQLCipher package doesn't support, you can fork GRDB yourself and include a custom copy of SQLCipher. This guide provides instructions for what is minimally required to get up and running with your fork:
+
+1. [Fork](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/fork-a-repo) GRDB
+2. Clone the repository on your machine
+
+```sh
+git clone <url to your fork>
+```
+3. Build the sqlite amalgamation w/SQLCipher (for example using the SQLCipher documentation for [Apple Source Integration](https://www.zetetic.net/sqlcipher/sqlcipher-apple-community/#source-integration)) to generate `sqlite3.c`/`sqlite3.h` files
+4. Open the GRDB Package.swift project in Xcode. Create a new Directory named SQLCipher in the Sources directory and move the `sqlite3.c`/`sqlite3.h` files in the directory structure like so
+
+```sh
+SQLCipher
+├── include
+│   ├── module.modulemap
+│   ├── SQLCipher
+│   │   └── sqlite3.h
+│   └── SQLCipher.h
+└── sqlite3.c
+```
+
+Add a `module.modulemap` file in the `include` directory with these contents
+
+```swift
+module SQLCipher {
+    umbrella header "SQLCipher.h"
+    export *
+}
+```
+
+Add a `SQLCipher.h` umbrella header file in the `include` directory with these contents
+
+```objc
+#ifndef SQLCipher_h
+#define SQLCipher_h
+
+#import <SQLCipher/sqlite3.h>
+#endif /* SQLCipher_h */
+```
+
+6. Modify the `Package.swift` to include the new SQLCipher target and add it as a depdency for GRDB
+
+```swift
+        .target(
+            name: "GRDB",
+            dependencies: [
+                // GRDB+SQLCipher: Uncomment the SQLCipher and GRDBSQLCipher dependencies
+                .target(name: "SQLCipher"),
+                .target(name: "GRDBSQLCipher"),
+            ],
+            path: "GRDB",
+            resources: [.copy("PrivacyInfo.xcprivacy")],
+            cSettings: cSettings,
+            swiftSettings: swiftSettings),
+        .target(
+            name: "SQLCipher",
+            publicHeadersPath: "include",
+            cSettings: cSettings
+        ),
+```
+
+7. Add these swiftSettings and cSettings to `Package.swift` (and whatever other flags desired)
+
+```swift
+swiftSettings.append(.define("SQLITE_HAS_CODEC"))
+swiftSettings.append(.define("SQLCipher"))
+```
+
+```swift
+cSettings.append(contentsOf: [
+    .define("NDEBUG", to: nil),
+    .define("SQLCIPHER_CRYPTO_CC", to: nil),
+    .define("SQLITE_HAS_CODEC", to: nil),
+    .define("SQLITE_TEMP_STORE", to: "2"),
+    .define("SQLITE_THREADSAFE", to: "1"),
+    .define("SQLITE_EXTRA_INIT", to: "sqlcipher_extra_init"),
+    .define("SQLITE_EXTRA_SHUTDOWN", to: "sqlcipher_extra_shutdown"),
+    .define("SQLITE_ENABLE_FTS5", to: nil),
+    .define("SQLITE_ENABLE_SNAPSHOT", to: nil)
+])
+```

README.md

@@ -4589,7 +4589,9 @@ Encryption
 
 **GRDB can encrypt your database with [SQLCipher](http://sqlcipher.net) v3.4+.**
 
-To use SQLCipher with the [Swift Package Manager](https://swift.org/package-manager/), you must fork GRDB, and modify `Package.swift`. Instructions are in the file itself, in comments that contain "GRDB+SQLCipher".
+To use SQLCipher with [Swift Package Manager](https://swift.org/package-manager/), you can use the officially supported [fork of GRDB w/SQLCipher](https://github.com/sqlcipher/GRDB.swift). This fork is maintained by the SQLCipher team in collaboration with GRDB and is the recommended fork to use to enable SQLCipher encryption for GRDB.
+
+If you have requirements that the official SQLCipher package doesn't support, you can fork GRDB yourself and include a custom copy of SQLCipher using these [instructions](Documentation/CustomSQLCipherBuilds.md)
 
 To use SQLCipher with [CocoaPods](http://cocoapods.org/), specify in your `Podfile`: