parser: consume finish handoff (#297)

Make Parser ~Copyable; move storage into TOMLDocument.

Author: dduan

Sources/TOMLDecoder/Parsing/Parser+Finish.swift

@@ -0,0 +1,24 @@
+extension Parser {
+    consuming func finish(source: String) -> TOMLDocument {
+        var tables: [InternalTOMLTable] = []
+        var arrays: [InternalTOMLArray] = []
+        var keyTables: [KeyTablePair] = []
+        var keyArrays: [KeyArrayPair] = []
+        var keyValues: [KeyValuePair] = []
+
+        swap(&tables, &self.tables)
+        swap(&arrays, &self.arrays)
+        swap(&keyTables, &self.keyTables)
+        swap(&keyArrays, &self.keyArrays)
+        swap(&keyValues, &self.keyValues)
+
+        return TOMLDocument(
+            source: source,
+            tables: tables,
+            arrays: arrays,
+            keyTables: keyTables,
+            keyArrays: keyArrays,
+            keyValues: keyValues
+        )
+    }
+}

Sources/TOMLDecoder/Parsing/Parser.swift

@@ -1,4 +1,4 @@
-struct Parser {
+struct Parser: ~Copyable {
     var token = Token.empty
     var cursor = 0
     var currentLineNumber = 1

Sources/TOMLDecoder/Parsing/TOMLDocument.swift

@@ -9,6 +9,22 @@ struct TOMLDocument: Equatable, @unchecked Sendable {
 
     let source: String
 
+    init(
+        source: String,
+        tables: [InternalTOMLTable],
+        arrays: [InternalTOMLArray],
+        keyTables: [KeyTablePair],
+        keyArrays: [KeyArrayPair],
+        keyValues: [KeyValuePair]
+    ) {
+        self.source = source
+        self.tables = tables
+        self.arrays = arrays
+        self.keyTables = keyTables
+        self.keyArrays = keyArrays
+        self.keyValues = keyValues
+    }
+
     init(source: String, keyTransform: (@Sendable (String) -> String)?) throws(TOMLError) {
         var hasContinousStorage = false
         var parser = Parser(keyTransform: keyTransform)
@@ -31,12 +47,7 @@ struct TOMLDocument: Equatable, @unchecked Sendable {
             }
         }
 
-        self.source = source
-        tables = parser.tables
-        arrays = parser.arrays
-        keyValues = parser.keyValues
-        keyTables = parser.keyTables
-        keyArrays = parser.keyArrays
+        self = parser.finish(source: source)
     }
 }