Merge pull request #22168 from benrimmington/sr-6127

[stdlib] Fix memory leaks in readLine()

Author: milseman

stdlib/public/SwiftShims/LibcShims.h

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -57,7 +57,7 @@ __swift_size_t _swift_stdlib_fwrite_stdout(const void *ptr, __swift_size_t size,
 
 // General utilities <stdlib.h>
 // Memory management functions
-static inline void _swift_stdlib_free(void *ptr) {
+static inline void _swift_stdlib_free(void *_Nullable ptr) {
   extern void free(void *);
   free(ptr);
 }

stdlib/public/core/InputStream.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -27,45 +27,18 @@ import SwiftShims
 /// - Returns: The string of characters read from standard input. If EOF has
 ///   already been reached when `readLine()` is called, the result is `nil`.
 public func readLine(strippingNewline: Bool = true) -> String? {
-  var linePtrVar: UnsafeMutablePointer<UInt8>?
-  var readBytes = swift_stdlib_readLine_stdin(&linePtrVar)
-  if readBytes == -1 {
-    return nil
+  var utf8Start: UnsafeMutablePointer<UInt8>?
+  let utf8Count = swift_stdlib_readLine_stdin(&utf8Start)
+  defer {
+    _swift_stdlib_free(utf8Start)
   }
-  _internalInvariant(readBytes >= 0,
-    "unexpected return value from swift_stdlib_readLine_stdin")
-  if readBytes == 0 {
-    return ""
+  guard utf8Count > 0 else {
+    return nil
   }
-
-  let linePtr = linePtrVar!
-  if strippingNewline {
-    // FIXME: Unicode conformance.  To fix this, we need to reimplement the
-    // code we call above to get a line, since it will only stop on LF.
-    //
-    // <rdar://problem/20013999> Recognize Unicode newlines in readLine()
-    //
-    // Recognize only LF and CR+LF combinations for now.
-    let cr = UInt8(ascii: "\r")
-    let lf = UInt8(ascii: "\n")
-    if readBytes == 1 && linePtr[0] == lf {
-      return ""
-    }
-    if readBytes >= 2 {
-      switch (linePtr[readBytes - 2], linePtr[readBytes - 1]) {
-      case (cr, lf):
-        readBytes -= 2
-        break
-      case (_, lf):
-        readBytes -= 1
-        break
-      default:
-        ()
-      }
-    }
+  let utf8Buffer = UnsafeBufferPointer(start: utf8Start, count: utf8Count)
+  var result = String._fromUTF8Repairing(utf8Buffer).result
+  if strippingNewline, result.last == "\n" || result.last == "\r\n" {
+    _ = result.removeLast()
   }
-  let result = String._fromUTF8Repairing(
-    UnsafeBufferPointer(start: linePtr, count: readBytes)).0
-  _swift_stdlib_free(linePtr)
   return result
 }

stdlib/public/stubs/Stubs.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -276,7 +276,7 @@ uint64_t swift_float80ToString(char *Buffer, size_t BufferLength,
 
 /// \param[out] LinePtr Replaced with the pointer to the malloc()-allocated
 /// line.  Can be NULL if no characters were read. This buffer should be
-/// freed by the caller if this function returns a positive value.
+/// freed by the caller.
 ///
 /// \returns Size of character data returned in \c LinePtr, or -1
 /// if an error occurred, or EOF was reached.