#if swift(>=5.8)
@_documentation(visibility: private)
#endif
fileprivate struct FfiConverterString: FfiConverter {
typealias SwiftType = String
typealias FfiType = RustBuffer
public static func lift(_ value: RustBuffer) throws -> String {
defer {
value.deallocate()
}
if value.data == nil {
return String()
}
let bytes = UnsafeBufferPointer<UInt8>(start: value.data!, count: Int(value.len))
// Use Swift's native UTF-8 decoder; `String(bytes:encoding:.utf8)` goes
// through Foundation's NSString and silently strips a leading U+FEFF BOM.
// Invalid UTF-8 substitutes U+FFFD instead of trapping (unreachable
// given Rust's `String` invariant).
return String(decoding: bytes, as: UTF8.self)
}
public static func lower(_ value: String) -> RustBuffer {
return value.utf8CString.withUnsafeBufferPointer { ptr in
// The swift string gives us int8_t, we want uint8_t.
ptr.withMemoryRebound(to: UInt8.self) { ptr in
// The swift string gives us a trailing null byte, we don't want it.
let buf = UnsafeBufferPointer(rebasing: ptr.prefix(upTo: ptr.count - 1))
return RustBuffer.from(buf)
}
}
}
public static func read(from buf: inout (data: Data, offset: Data.Index)) throws -> String {
let len: Int32 = try readInt(&buf)
// See `lift` above for why we avoid Foundation's NSString-backed decoder here.
return String(decoding: try readBytes(&buf, count: Int(len)), as: UTF8.self)
}
public static func write(_ value: String, into buf: inout [UInt8]) {
let len = Int32(value.utf8.count)
writeInt(&buf, len)
writeBytes(&buf, value.utf8)
}
}