refactor: Buffer RAII

ios/zerokit-ios/zerokit-ios.xcodeproj/project.pbxproj

@@ -16,6 +16,7 @@
 		7961AA77293428FD00B52AA9 /* rln.wasm in Resources */ = {isa = PBXBuildFile; fileRef = 7961AA74293428FD00B52AA9 /* rln.wasm */; };
 		7961AA7929342D2C00B52AA9 /* verification_key.json in Resources */ = {isa = PBXBuildFile; fileRef = 7961AA7829342D2C00B52AA9 /* verification_key.json */; };
 		799E22A12938FB5D004476D7 /* zerokit.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799E22A02938FB5D004476D7 /* zerokit.swift */; };
+		799E22A329390A44004476D7 /* CBuffer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 799E22A229390A44004476D7 /* CBuffer.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -30,6 +31,7 @@
 		7961AA74293428FD00B52AA9 /* rln.wasm */ = {isa = PBXFileReference; lastKnownFileType = file; name = rln.wasm; path = ../../resources/rln.wasm; sourceTree = "<group>"; };
 		7961AA7829342D2C00B52AA9 /* verification_key.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; name = verification_key.json; path = ../../resources/verification_key.json; sourceTree = "<group>"; };
 		799E22A02938FB5D004476D7 /* zerokit.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = zerokit.swift; sourceTree = "<group>"; };
+		799E22A229390A44004476D7 /* CBuffer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CBuffer.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -72,6 +74,7 @@
 				7961AA74293428FD00B52AA9 /* rln.wasm */,
 				791439182933B320003246AC /* Preview Content */,
 				799E22A02938FB5D004476D7 /* zerokit.swift */,
+				799E22A229390A44004476D7 /* CBuffer.swift */,
 			);
 			path = "zerokit-ios";
 			sourceTree = "<group>";
@@ -176,6 +179,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				799E22A12938FB5D004476D7 /* zerokit.swift in Sources */,
+				799E22A329390A44004476D7 /* CBuffer.swift in Sources */,
 				791439152933B31F003246AC /* ContentView.swift in Sources */,
 				791439132933B31F003246AC /* zerokit_iosApp.swift in Sources */,
 			);

ios/zerokit-ios/zerokit-ios/CBuffer.swift

@@ -0,0 +1,45 @@
+import Foundation
+
+class CBuffer {
+    let bufferPtr: UnsafeMutablePointer<Buffer>
+    
+    init(input: inout [UInt8]) {
+        bufferPtr = CBuffer.toPointer(input: &input)
+    }
+    
+    init() {
+        let size = MemoryLayout<Buffer>.stride
+        bufferPtr = UnsafeMutablePointer<Buffer>.allocate(capacity: size)
+    }
+    
+    deinit {
+        bufferPtr.deallocate()
+    }
+    
+    // toBuffer converts the input to a buffer object that is used to communicate data with the rln lib
+    private static func toBuffer(data: inout [UInt8]) -> Buffer {
+        let result = sliceToPtr(data: &data)
+        return Buffer(
+            ptr: result.dataPtr,
+            len: uintptr_t(result.dataLen)
+        )
+    }
+
+    private static func sliceToPtr(data: inout [UInt8]) -> (dataPtr: UnsafePointer<UInt8>?, dataLen: CInt) {
+        if data.count == 0 {
+            return (nil, CInt(0))
+        } else {
+            let uint8Pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: data.count)
+            uint8Pointer.initialize(from: &data, count: data.count)
+            return (UnsafePointer<UInt8>(uint8Pointer), CInt(data.count))
+        }
+    }
+    
+    private static func toPointer(input: inout [UInt8]) -> UnsafeMutablePointer<Buffer> {
+        let buf = toBuffer(data: &input)
+        let size = MemoryLayout.stride(ofValue: buf)
+        let allocB = UnsafeMutablePointer<Buffer>.allocate(capacity: size)
+        allocB.initialize(to: buf)
+        return allocB
+    }
+}

ios/zerokit-ios/zerokit-ios/zerokit.swift

@@ -1,33 +1,5 @@
 import Foundation
 
-// toBuffer converts the input to a buffer object that is used to communicate data with the rln lib
-func toBuffer(data: inout [UInt8]) -> Buffer {
-    let result = sliceToPtr(data: &data)
-    return Buffer(
-        ptr: result.dataPtr,
-        len: uintptr_t(result.dataLen)
-    )
-}
-
-func sliceToPtr(data: inout [UInt8]) -> (dataPtr: UnsafePointer<UInt8>?, dataLen: CInt) {
-    if data.count == 0 {
-        return (nil, CInt(0))
-    } else {
-        let uint8Pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: data.count)
-        uint8Pointer.initialize(from: &data, count: data.count)
-        return (UnsafePointer<UInt8>(uint8Pointer), CInt(data.count))
-      // return (UnsafePointer<UInt8>(data), CInt(data.count))
-    }
-}
-
-func toCBufferPtr(input: inout [UInt8]) -> UnsafeMutablePointer<Buffer> {
-    let buf = toBuffer(data: &input)
-    let size = MemoryLayout.stride(ofValue: buf)
-    let allocB = UnsafeMutablePointer<Buffer>.allocate(capacity: size)
-    allocB.initialize(to: buf)
-    return allocB
-}
-
 func readFile(filename: String, filetype: String) -> [UInt8] {
     do {
         let path = Bundle.main.path(forResource: filename, ofType: filetype)
@@ -40,16 +12,11 @@ func readFile(filename: String, filetype: String) -> [UInt8] {
     return [UInt8]()
 }
 
-func createOutputBuffer() -> UnsafeMutablePointer<Buffer> {
-    let size = MemoryLayout<Buffer>.stride
-    return UnsafeMutablePointer<Buffer>.allocate(capacity: size)
-}
-
 func generateCredentials(ctx: OpaquePointer!) -> [UInt8] {
     // Generating credentials ======
-    let credentialBuffer = createOutputBuffer()
+    let credentialBuffer = CBuffer()
-    if key_gen(ctx, credentialBuffer) {
+    if key_gen(ctx, credentialBuffer.bufferPtr) {
-        let bufferPointer = UnsafeRawBufferPointer(start: credentialBuffer.pointee.ptr, count: Int(credentialBuffer.pointee.len))
+        let bufferPointer = UnsafeRawBufferPointer(start: credentialBuffer.bufferPtr.pointee.ptr, count: Int(credentialBuffer.bufferPtr.pointee.len))
         var generatedKeyBytes = [UInt8]()
         bufferPointer.withUnsafeBytes {
             generatedKeyBytes.append(contentsOf: $0)
@@ -65,9 +32,9 @@ func generateCredentials(ctx: OpaquePointer!) -> [UInt8] {
 }
 
 func getMerkleRoot(ctx: OpaquePointer!) -> [UInt8] {
-    let rootBuffer = createOutputBuffer()
+    let output = CBuffer()
-    if get_root(ctx, rootBuffer) {
+    if get_root(ctx, output.bufferPtr) {
-        let bufferPointer = UnsafeRawBufferPointer(start: rootBuffer.pointee.ptr, count: Int(rootBuffer.pointee.len))
+        let bufferPointer = UnsafeRawBufferPointer(start: output.bufferPtr.pointee.ptr, count: Int(output.bufferPtr.pointee.len))
         var rootBytes = [UInt8]()
         bufferPointer.withUnsafeBytes {
             rootBytes.append(contentsOf: $0)
@@ -85,14 +52,14 @@ func newRLN() -> String {
     var zkey_bytes = readFile(filename: "rln_final", filetype: "zkey")
     var vk_bytes = readFile(filename: "verification_key", filetype: "json")
     
-    let circom_buffer = toCBufferPtr(input: &circom_bytes)
+    let circom_buffer = CBuffer(input: &circom_bytes)
-    let zkey_buffer = toCBufferPtr(input: &zkey_bytes)
+    let zkey_buffer = CBuffer(input: &zkey_bytes)
-    let vk_buffer = toCBufferPtr(input: &vk_bytes)
+    let vk_buffer = CBuffer(input: &vk_bytes)
     
     // Instantiating RLN object
     let objUnsafeMutablePtr = UnsafeMutablePointer<AnyObject>.allocate(capacity: 1)
     var ctx : OpaquePointer! = OpaquePointer(objUnsafeMutablePtr)
-    if !new_with_params(20, circom_buffer, zkey_buffer, vk_buffer, &ctx) {
+    if !new_with_params(20, circom_buffer.bufferPtr, zkey_buffer.bufferPtr, vk_buffer.bufferPtr, &ctx) {
         // TODO: throw error
     }