Merge pull request #22 from vapor/cc-fixes

conditional conformance fixes
vapor · Feb 27, 2018 · 2d93ec3 · 2d93ec3
2 parents 25a0435 + a226381
commit 2d93ec3
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Showing 4 changed files with 74 additions and 28 deletions.
diff --git a/Sources/PostgreSQL/Data/PostgreSQLArrayCustomConvertible.swift b/Sources/PostgreSQL/Data/PostgreSQLArrayCustomConvertible.swift
@@ -1,9 +1,9 @@
 import Foundation
 
 /// Representable by a `T[]` column on the PostgreSQL database.
-public protocol PostgreSQLArrayCustomConvertible: PostgreSQLDataCustomConvertible, Codable {
+public protocol PostgreSQLArrayCustomConvertible: PostgreSQLDataCustomConvertible {
     /// The associated array element type
-    associatedtype PostgreSQLArrayElement: PostgreSQLDataCustomConvertible
+    associatedtype PostgreSQLArrayElement // : PostgreSQLDataCustomConvertible
 
     /// Convert an array of elements to self.
     static func convertFromPostgreSQLArray(_ data: [PostgreSQLArrayElement]) -> Self
@@ -13,11 +13,6 @@ public protocol PostgreSQLArrayCustomConvertible: PostgreSQLDataCustomConvertibl
 }
 
 extension PostgreSQLArrayCustomConvertible {
-    /// See `PostgreSQLDataCustomConvertible.postgreSQLDataType`
-    public static var postgreSQLDataType: PostgreSQLDataType {
-        return PostgreSQLArrayElement.postgreSQLDataArrayType
-    }
-
     /// See `PostgreSQLDataCustomConvertible.convertFromPostgreSQLData(_:)`
     public static func convertFromPostgreSQLData(_ data: PostgreSQLData) throws -> Self {
         guard var value = data.data else {
@@ -35,8 +30,8 @@ extension PostgreSQLArrayCustomConvertible {
                 let count = Int(value.extract(Int32.self).bigEndian)
                 let subValue = value.extract(count: count)
                 let psqlData = PostgreSQLData(type: metadata.type, format: data.format, data: subValue)
-                let element = try PostgreSQLArrayElement.convertFromPostgreSQLData(psqlData)
-                array.append(element)
+                let element = try requirePostgreSQLDataCustomConvertible(PostgreSQLArrayElement.self).convertFromPostgreSQLData(psqlData)
+                array.append(element as! PostgreSQLArrayElement)
             }
         } else {
             array = []
@@ -48,13 +43,13 @@ extension PostgreSQLArrayCustomConvertible {
     /// See `PostgreSQLDataCustomConvertible.convertToPostgreSQLData()`
     public func convertToPostgreSQLData() throws -> PostgreSQLData {
         let elements = try convertToPostgreSQLArray().map {
-            try $0.convertToPostgreSQLData()
+            try requirePostgreSQLDataCustomConvertible($0).convertToPostgreSQLData()
         }
 
         var data = Data()
         data += Int32(1).data // non-null
         data += Int32(0).data // b
-        data += PostgreSQLArrayElement.postgreSQLDataType.raw.data // type
+        data += requirePostgreSQLDataCustomConvertible(PostgreSQLArrayElement.self).postgreSQLDataType.raw.data // type
         data += Int32(elements.count).data // length
         data += Int32(1).data // dimensions
 
@@ -67,7 +62,7 @@ extension PostgreSQLArrayCustomConvertible {
             }
         }
 
-        return PostgreSQLData(type: PostgreSQLArrayElement.postgreSQLDataArrayType, format: .binary, data: data)
+        return PostgreSQLData(type: requirePostgreSQLDataCustomConvertible(PostgreSQLArrayElement.self).postgreSQLDataArrayType, format: .binary, data: data)
     }
 }
 
@@ -107,10 +102,15 @@ extension PostgreSQLArrayMetadata: CustomStringConvertible {
     }
 }
 
-extension Array: PostgreSQLArrayCustomConvertible where Element: Codable, Element: PostgreSQLDataCustomConvertible {
+extension Array: PostgreSQLArrayCustomConvertible {
     /// See `PostgreSQLArrayCustomConvertible.postgreSQLDataArrayType`
     public static var postgreSQLDataArrayType: PostgreSQLDataType {
-        return Element.postgreSQLDataArrayType
+        fatalError("Multi-dimensional arrays are not yet supported.")
+    }
+
+    /// See `PostgreSQLDataCustomConvertible.postgreSQLDataType`
+    public static var postgreSQLDataType: PostgreSQLDataType {
+        return requirePostgreSQLDataCustomConvertible(Element.self).postgreSQLDataArrayType
     }
 
     /// See `PostgreSQLArrayCustomConvertible.PostgreSQLArrayElement`
@@ -126,3 +126,17 @@ extension Array: PostgreSQLArrayCustomConvertible where Element: Codable, Elemen
         return self
     }
 }
+
+func requirePostgreSQLDataCustomConvertible<T>(_ type: T.Type) -> PostgreSQLDataCustomConvertible.Type {
+    guard let custom = T.self as? PostgreSQLDataCustomConvertible.Type else {
+        fatalError("`\(T.self)` does not conform to `PostgreSQLDataCustomConvertible`")
+    }
+    return custom
+}
+
+func requirePostgreSQLDataCustomConvertible<T>(_ type: T) -> PostgreSQLDataCustomConvertible {
+    guard let custom = type as? PostgreSQLDataCustomConvertible else {
+        fatalError("`\(T.self)` does not conform to `PostgreSQLDataCustomConvertible`")
+    }
+    return custom
+}
diff --git a/Sources/PostgreSQL/Data/PostgreSQLData+Optional.swift b/Sources/PostgreSQL/Data/PostgreSQLData+Optional.swift
@@ -1,33 +1,32 @@
 import Async
 import Foundation
 
-extension OptionalType where Self.WrappedType: PostgreSQLDataCustomConvertible {
+extension OptionalType {
     /// See `PostgreSQLDataCustomConvertible.convertFromPostgreSQLData(_:)`
     public static func convertFromPostgreSQLData(_ data: PostgreSQLData) throws -> Self {
-        let wrapped = try WrappedType.convertFromPostgreSQLData(data)
-        return Self.makeOptionalType(wrapped)
+        let wrapped = try requirePostgreSQLDataCustomConvertible(WrappedType.self).convertFromPostgreSQLData(data)
+        return Self.makeOptionalType(wrapped as? WrappedType)
     }
 
     /// See `PostgreSQLDataCustomConvertible.convertToPostgreSQLData()`
     public func convertToPostgreSQLData() throws -> PostgreSQLData {
         if let wrapped = self.wrapped {
-            return try wrapped.convertToPostgreSQLData()
+            return try requirePostgreSQLDataCustomConvertible(wrapped).convertToPostgreSQLData()
         } else {
             return PostgreSQLData(type: .void, format: .binary, data: nil)
         }
     }
 }
 
-extension Optional: PostgreSQLDataCustomConvertible where Wrapped: PostgreSQLDataCustomConvertible {
+extension Optional: PostgreSQLDataCustomConvertible {
     /// See `PostgreSQLDataCustomConvertible.postgreSQLDataType`
     public static var postgreSQLDataType: PostgreSQLDataType {
-        return Wrapped.postgreSQLDataType
+        return requirePostgreSQLDataCustomConvertible(Wrapped.self).postgreSQLDataType
     }
 
 
     /// See `PostgreSQLDataCustomConvertible.postgreSQLDataArrayType`
     public static var postgreSQLDataArrayType: PostgreSQLDataType {
-        return Wrapped.postgreSQLDataArrayType
+        return requirePostgreSQLDataCustomConvertible(Wrapped.self).postgreSQLDataArrayType
     }
 }
-
diff --git a/Sources/PostgreSQL/Data/PostgreSQLJSONCustomConvertible.swift b/Sources/PostgreSQL/Data/PostgreSQLJSONCustomConvertible.swift
@@ -2,7 +2,7 @@ import COperatingSystem
 import Foundation
 
 /// Representable by a `JSONB` column on the PostgreSQL database.
-public protocol PostgreSQLJSONCustomConvertible: PostgreSQLDataCustomConvertible, Codable { }
+public protocol PostgreSQLJSONCustomConvertible: PostgreSQLDataCustomConvertible { }
 
 extension PostgreSQLJSONCustomConvertible {
     /// See `PostgreSQLDataCustomConvertible.postgreSQLDataType`
@@ -17,22 +17,55 @@ extension PostgreSQLJSONCustomConvertible {
             throw PostgreSQLError(identifier: "data", reason: "Unable to decode PostgreSQL JSON from `null` data.", source: .capture())
         }
 
+
+        guard let decodable = Self.self as? Decodable.Type else {
+            fatalError("`\(Self.self)` is not `Decodable`.")
+        }
+
         switch data.type {
         case .jsonb:
             switch data.format {
-            case .text: return try JSONDecoder().decode(Self.self, from: value)
+            case .text:
+                let decoder = try JSONDecoder().decode(DecoderUnwrapper.self, from: value).decoder
+                return try decodable.init(from: decoder) as! Self
             case .binary:
                 assert(value[0] == 0x01)
-                return try JSONDecoder().decode(Self.self, from: value[1...])
+                let decoder = try JSONDecoder().decode(DecoderUnwrapper.self, from: value[1...]).decoder
+                return try decodable.init(from: decoder) as! Self
             }
         default: throw PostgreSQLError(identifier: "json", reason: "Could not decode \(Self.self) from data type: \(data.type).", source: .capture())
         }
     }
 
     /// See `PostgreSQLDataCustomConvertible.convertToPostgreSQLData()`
     public func convertToPostgreSQLData() throws -> PostgreSQLData {
-        return try PostgreSQLData(type: .jsonb, format: .text, data: JSONEncoder().encode(self))
+        guard let encodable = self as? Encodable else {
+            fatalError("`\(Self.self)` is not `Encodable`.")
+        }
+        return try PostgreSQLData(
+            type: .jsonb,
+            format: .text,
+            data: JSONEncoder().encode(EncoderWrapper(encodable))
+        )
+    }
+}
+
+extension Dictionary: PostgreSQLJSONCustomConvertible { }
+
+fileprivate struct DecoderUnwrapper: Decodable {
+    let decoder: Decoder
+    init(from decoder: Decoder) {
+        self.decoder = decoder
+    }
+}
+
+fileprivate struct EncoderWrapper: Encodable {
+    var encodable: Encodable
+    init(_ encodable: Encodable) {
+        self.encodable = encodable
+    }
+    func encode(to encoder: Encoder) throws {
+        try encodable.encode(to: encoder)
     }
 }
 
-extension Dictionary: PostgreSQLJSONCustomConvertible where Key: Codable, Value: Codable { }
diff --git a/Tests/PostgreSQLTests/PostgreSQLConnectionTests.swift b/Tests/PostgreSQLTests/PostgreSQLConnectionTests.swift
@@ -247,7 +247,7 @@ class PostgreSQLConnectionTests: XCTestCase {
     }
 
     func testStruct() throws {
-        struct Hello: PostgreSQLJSONCustomConvertible {
+        struct Hello: PostgreSQLJSONCustomConvertible, Codable {
             var message: String
         }