swift: Revamp source printing to ensure escaping everywhere

The source generator now operates using a string wrapper type called
`SwiftSource`. Identifiers are escaped when converting into
`SwiftSource` values, with an alternative method for producing escaped
string literals. An escape hatch is provided for disabling escapes, but
the default behavior is to escape all identifiers in the dynamic input.

Most `SwiftSource` values are produced by a tagged template literal,
which allows for easy mixing of string literals containing Swift
keywords and dynamic input that needs escaping.

As part of this, rewrite string escaping such that it actually escapes
string contents properly. This required fixing a test that had a bad
spec enforcing broken behavior.

Fixes apollographql/apollo-ios#193.
Fixes apollographql/apollo-ios#752.

packages/apollo-codegen-swift/src/__tests__/__snapshots__/codeGeneration.ts.snap

@@ -108,7 +108,7 @@ exports[`Swift code generation #classDeclarationForOperation() should correctly
   ///   }
   /// }
   public let operationDefinition =
-    \\"mutation CreateReview($episode: Episode) {\\\\n  createReview(episode: $episode, review: {stars: 5, commentary: \\\\\\"\\\\\\"\\\\\\"\\\\n    Wow!\\\\n     I thought\\\\n      This movie \\\\ ROCKED!\\\\n  \\\\\\"\\\\\\"\\\\\\"}) {\\\\n    stars\\\\n    commentary\\\\n  }\\\\n}\\"
+    \\"mutation CreateReview($episode: Episode) {\\\\n  createReview(episode: $episode, review: {stars: 5, commentary: \\\\\\"\\\\\\"\\\\\\"\\\\n    Wow!\\\\n     I thought\\\\n      This movie \\\\\\\\ ROCKED!\\\\n  \\\\\\"\\\\\\"\\\\\\"}) {\\\\n    stars\\\\n    commentary\\\\n  }\\\\n}\\"
 
   public let operationName = \\"CreateReview\\"
 

packages/apollo-codegen-swift/src/__tests__/codeGeneration.ts

@@ -222,7 +222,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: GraphQLString
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -232,7 +232,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLNonNull(GraphQLString)
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -242,7 +242,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLList(GraphQLString)
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -252,7 +252,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLList(new GraphQLNonNull(GraphQLString))
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -262,7 +262,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLNonNull(new GraphQLList(GraphQLString))
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -274,7 +274,7 @@ describe("Swift code generation", () => {
           type: new GraphQLNonNull(
             new GraphQLList(new GraphQLNonNull(GraphQLString))
           )
-        })
+        }).source
       ).toBe('"response_key": propertyName');
     });
 
@@ -284,7 +284,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: schema.getType("Droid")
-        })
+        }).source
       ).toBe(
         '"response_key": propertyName.flatMap { (value: Droid) -> ResultMap in value.resultMap }'
       );
@@ -296,7 +296,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLNonNull(schema.getType("Droid"))
-        })
+        }).source
       ).toBe('"response_key": propertyName.resultMap');
     });
 
@@ -306,7 +306,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLList(schema.getType("Droid"))
-        })
+        }).source
       ).toBe(
         '"response_key": propertyName.flatMap { (value: [Droid?]) -> [ResultMap?] in value.map { (value: Droid?) -> ResultMap? in value.flatMap { (value: Droid) -> ResultMap in value.resultMap } } }'
       );
@@ -318,7 +318,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLList(new GraphQLNonNull(schema.getType("Droid")))
-        })
+        }).source
       ).toBe(
         '"response_key": propertyName.flatMap { (value: [Droid]) -> [ResultMap] in value.map { (value: Droid) -> ResultMap in value.resultMap } }'
       );
@@ -330,7 +330,7 @@ describe("Swift code generation", () => {
           responseKey: "response_key",
           propertyName: "propertyName",
           type: new GraphQLNonNull(new GraphQLList(schema.getType("Droid")))
-        })
+        }).source
       ).toBe(
         '"response_key": propertyName.map { (value: Droid?) -> ResultMap? in value.flatMap { (value: Droid) -> ResultMap in value.resultMap } }'
       );
@@ -344,7 +344,7 @@ describe("Swift code generation", () => {
           type: new GraphQLNonNull(
             new GraphQLList(new GraphQLNonNull(schema.getType("Droid")))
           )
-        })
+        }).source
       ).toBe(
         '"response_key": propertyName.map { (value: Droid) -> ResultMap in value.resultMap }'
       );
@@ -661,7 +661,7 @@ describe("Swift code generation", () => {
         .selectionSet.selections[0] as Field).args as Argument[];
       const dictionaryLiteral = generator.helpers.dictionaryLiteralForFieldArguments(
         fieldArguments
-      );
+      ).source;
 
       expect(dictionaryLiteral).toBe(
         '["episode": "JEDI", "review": ["stars": 2, "commentary": GraphQLVariable("commentary"), "favorite_color": ["red": GraphQLVariable("red"), "blue": 100, "green": 50]]]'

packages/apollo-codegen-swift/src/__tests__/language.ts

@@ -1,6 +1,6 @@
 import { stripIndent } from "common-tags";
 
-import { SwiftGenerator } from "../language";
+import { SwiftGenerator, SwiftSource, swift } from "../language";
 
 describe("Swift code generation: Basic language constructs", () => {
   let generator: SwiftGenerator<any>;
@@ -264,3 +264,95 @@ describe("Swift code generation: Basic language constructs", () => {
     expect(generator.output).toMatchSnapshot();
   });
 });
+
+describe("Swift code generation: Escaping", () => {
+  describe("using SwiftSource", () => {
+    it(`should escape identifiers`, () => {
+      expect(SwiftSource.identifier("self").source).toBe("`self`");
+      expect(SwiftSource.identifier("public").source).toBe("`public`");
+      expect(SwiftSource.identifier("Array<Type>").source).toBe(
+        "Array<`Type`>"
+      );
+      expect(SwiftSource.identifier("[Self?]?").source).toBe("[`Self`?]?");
+    });
+
+    it(`should not escape other words`, () => {
+      expect(SwiftSource.identifier("me").source).toBe("me");
+      expect(SwiftSource.identifier("_Self").source).toBe("_Self");
+      expect(SwiftSource.identifier("classes").source).toBe("classes");
+    });
+
+    it(`should escape fewer words in member position`, () => {
+      expect(SwiftSource.identifier(".self").source).toBe(".`self`");
+      expect(SwiftSource.identifier(".public").source).toBe(".public");
+      expect(SwiftSource.identifier("Foo.Self.Type.self.class").source).toBe(
+        "Foo.Self.`Type`.`self`.class"
+      );
+    });
+
+    it(`should escape fewer words at offset 0 with member escaping`, () => {
+      expect(SwiftSource.memberName("self").source).toBe("`self`");
+      expect(SwiftSource.memberName("public").source).toBe("public");
+      expect(SwiftSource.memberName(" public").source).toBe(" `public`");
+      expect(SwiftSource.memberName("Foo.Self.Type.self.class").source).toBe(
+        "Foo.Self.`Type`.`self`.class"
+      );
+    });
+
+    it(`should escape strings`, () => {
+      expect(SwiftSource.string("foobar").source).toBe('"foobar"');
+      expect(SwiftSource.string("foo\n  bar  ").source).toBe('"foo\\n  bar  "');
+      expect(SwiftSource.string("one'two\"three\\four\tfive").source).toBe(
+        '"one\'two\\"three\\\\four\\tfive"'
+      );
+    });
+
+    it(`should trim strings when asked`, () => {
+      expect(SwiftSource.string("foobar", true).source).toBe('"foobar"');
+      expect(SwiftSource.string("foo\n  bar  ", true).source).toBe('"foo bar"');
+    });
+  });
+  describe("using SwiftGenerator", () => {
+    let generator: SwiftGenerator<any>;
+
+    beforeEach(() => {
+      generator = new SwiftGenerator({});
+    });
+
+    it(`should trim with multilineString`, () => {
+      generator.multilineString("foo\n  bar  ");
+
+      expect(generator.output).toBe('"foo bar"');
+    });
+
+    it(`shouldn't trim with multilineString when using """`, () => {
+      generator.multilineString('"""\nfoo\n  bar  \n"""');
+      expect(generator.output).toBe('"\\"\\"\\"\\nfoo\\n  bar  \\n\\"\\"\\""');
+    });
+  });
+  describe("using template strings", () => {
+    it(`should escape interpolated strings but not string literals`, () => {
+      expect(swift`self`.source).toBe("self");
+      expect(swift`${"self"}`.source).toBe("`self`");
+      expect(swift`class ${"Foo.Type.self"}: ${"Protocol?"}`.source).toBe(
+        "class Foo.`Type`.`self`: `Protocol`?"
+      );
+      expect(swift`${["Self", "Foo.Self.self"]}`.source).toBe(
+        "`Self`,Foo.Self.`self`"
+      );
+      expect(swift`${true} ${"true"}`.source).toBe("true `true`");
+      expect(swift`${{ toString: () => "self" }}`.source).toBe("`self`");
+    });
+
+    it(`should not escape already-escaped interpolated strings`, () => {
+      expect(swift`${swift`${"self"}`}`.source).toBe("`self`");
+      expect(swift`${"public"} ${new SwiftSource("public")}`.source).toBe(
+        "`public` public"
+      );
+    });
+
+    it(`should not escape with the raw tag`, () => {
+      expect(SwiftSource.raw`${"self"}`.source).toBe("self");
+    });
+  });
+});