1 files changed, 202 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/testExternalStrings.cpp b/js/src/jsapi-tests/testExternalStrings.cpp
new file mode 100644
index 0000000000..7b615f39c6
--- /dev/null
+++ b/js/src/jsapi-tests/testExternalStrings.cpp
@@ -0,0 +1,202 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "js/CharacterEncoding.h"  // JS::FindSmallestEncoding, JS::SmallestEncoding
+#include "js/GCAPI.h"  // JSExternalStringCallbacks, JS_NewExternalUCString, JS_NewExternalStringLatin1, JS_NewMaybeExternalStringUTF8, JS::AutoRequireNoGC
+#include "js/String.h"  // JS::IsExternalStringLatin1
+#include "jsapi-tests/tests.h"
+#include "util/Text.h"
+
+static const char16_t arr[] = u"hi, don't delete me";
+static const size_t arrlen = js_strlen(arr);
+
+static const char arr2[] = "hi, don't delete me";
+static const size_t arrlen2 = js_strlen(arr2);
+
+static int finalized1 = 0;
+static int finalized2 = 0;
+static int finalized3 = 0;
+static int finalized4 = 0;
+
+struct ExternalStringCallbacks : public JSExternalStringCallbacks {
+  int* finalizedCount = nullptr;
+  bool isTwoBytes = false;
+
+  explicit ExternalStringCallbacks(int* finalizedCount, bool isTwoBytes)
+      : finalizedCount(finalizedCount), isTwoBytes(isTwoBytes) {}
+
+  void finalize(JS::Latin1Char* chars) const override {
+    MOZ_ASSERT(!isTwoBytes);
+    MOZ_ASSERT(chars == (JS::Latin1Char*)arr2);
+    (*finalizedCount)++;
+  }
+
+  void finalize(char16_t* chars) const override {
+    MOZ_ASSERT(isTwoBytes);
+    MOZ_ASSERT(chars == arr);
+    (*finalizedCount)++;
+  }
+
+  size_t sizeOfBuffer(const JS::Latin1Char* chars,
+                      mozilla::MallocSizeOf mallocSizeOf) const override {
+    MOZ_CRASH("Unexpected call");
+  }
+
+  size_t sizeOfBuffer(const char16_t* chars,
+                      mozilla::MallocSizeOf mallocSizeOf) const override {
+    MOZ_CRASH("Unexpected call");
+  }
+};
+
+static const ExternalStringCallbacks callbacks1(&finalized1, true);
+static const ExternalStringCallbacks callbacks2(&finalized2, true);
+static const ExternalStringCallbacks callbacks3(&finalized3, false);
+static const ExternalStringCallbacks callbacks4(&finalized4, false);
+
+BEGIN_TEST(testExternalStrings) {
+  const unsigned N = 1000;
+
+  for (unsigned i = 0; i < N; ++i) {
+    CHECK(JS_NewExternalUCString(cx, arr, arrlen, &callbacks1));
+    CHECK(JS_NewExternalUCString(cx, arr, arrlen, &callbacks2));
+    CHECK(JS_NewExternalStringLatin1(cx, (JS::Latin1Char*)arr2, arrlen2,
+                                     &callbacks3));
+    CHECK(JS_NewExternalStringLatin1(cx, (JS::Latin1Char*)arr2, arrlen2,
+                                     &callbacks4));
+  }
+
+  JS_GC(cx);
+
+  CHECK((N - finalized1) == 0);
+  CHECK((N - finalized2) == 0);
+  CHECK((N - finalized3) == 0);
+  CHECK((N - finalized4) == 0);
+
+  return true;
+}
+END_TEST(testExternalStrings)
+
+struct SimpleExternalStringCallbacks : public JSExternalStringCallbacks {
+  SimpleExternalStringCallbacks() = default;
+
+  void finalize(JS::Latin1Char* chars) const override {}
+
+  void finalize(char16_t* chars) const override {
+    MOZ_CRASH("Unexpected call");
+  }
+
+  size_t sizeOfBuffer(const JS::Latin1Char* chars,
+                      mozilla::MallocSizeOf mallocSizeOf) const override {
+    MOZ_CRASH("Unexpected call");
+  }
+
+  size_t sizeOfBuffer(const char16_t* chars,
+                      mozilla::MallocSizeOf mallocSizeOf) const override {
+    MOZ_CRASH("Unexpected call");
+  }
+};
+
+static const SimpleExternalStringCallbacks simpleCallback;
+
+static const char utf8ASCII[] = "hi, I'm UTF-8 string";
+static const size_t utf8ASCIILen = js_strlen(utf8ASCII);
+
+static const char utf8Latin1[] = "hi, I'm \xC3\x9CTF-8 string";
+static const size_t utf8Latin1Len = js_strlen(utf8Latin1);
+
+static const char latin1[] = "hi, I'm \xDCTF-8 string";
+static const size_t latin1Len = js_strlen(latin1);
+
+static const char utf8UTF16[] = "hi, I'm UTF-\xEF\xBC\x98 string";
+static const size_t utf8UTF16Len = js_strlen(utf8UTF16);
+
+static const char16_t utf16[] = u"hi, I'm UTF-８ string";
+static const size_t utf16Len = js_strlen(utf16);
+
+BEGIN_TEST(testExternalStringsUTF8) {
+  // UTF-8 chars with ASCII range content should be converted into external
+  // string.
+  {
+    JS::UTF8Chars utf8Chars(utf8ASCII, utf8ASCIILen);
+    CHECK(JS::FindSmallestEncoding(utf8Chars) == JS::SmallestEncoding::ASCII);
+    bool allocatedExternal = false;
+    JS::Rooted<JSString*> str(
+        cx, JS_NewMaybeExternalStringUTF8(cx, utf8Chars, &simpleCallback,
+                                          &allocatedExternal));
+    CHECK(str);
+    CHECK(allocatedExternal);
+
+    const JSExternalStringCallbacks* callbacks = nullptr;
+    const JS::Latin1Char* chars = nullptr;
+    CHECK(JS::IsExternalStringLatin1(str, &callbacks, &chars));
+    CHECK(callbacks == &simpleCallback);
+    CHECK((void*)chars == (void*)utf8ASCII);
+
+    CHECK(StringHasLatin1Chars(str));
+
+    JS::AutoAssertNoGC nogc(cx);
+    size_t length;
+    chars = JS_GetLatin1StringCharsAndLength(cx, nogc, str, &length);
+    CHECK(length == utf8ASCIILen);
+    CHECK(memcmp(chars, utf8ASCII, length) == 0);
+  }
+
+  // UTF-8 chars with latin-1 range content shouldn't be converted into external
+  // string, but regular latin-1 string.
+  {
+    JS::UTF8Chars utf8Chars(utf8Latin1, utf8Latin1Len);
+    CHECK(JS::FindSmallestEncoding(utf8Chars) == JS::SmallestEncoding::Latin1);
+    bool allocatedExternal = false;
+    JS::Rooted<JSString*> str(
+        cx, JS_NewMaybeExternalStringUTF8(cx, utf8Chars, &simpleCallback,
+                                          &allocatedExternal));
+    CHECK(str);
+    CHECK(!allocatedExternal);
+
+    const JSExternalStringCallbacks* callbacks = nullptr;
+    const JS::Latin1Char* chars = nullptr;
+    CHECK(!JS::IsExternalStringLatin1(str, &callbacks, &chars));
+    CHECK(!callbacks);
+    CHECK(!chars);
+
+    CHECK(StringHasLatin1Chars(str));
+
+    JS::AutoAssertNoGC nogc(cx);
+    size_t length;
+    chars = JS_GetLatin1StringCharsAndLength(cx, nogc, str, &length);
+    CHECK(length == latin1Len);
+    CHECK(memcmp(chars, latin1, length) == 0);
+  }
+
+  // UTF-8 chars with UTF-16 range content shouldn't be converted into external
+  // string, but regular TwoBytes string.
+  {
+    JS::UTF8Chars utf8Chars(utf8UTF16, utf8UTF16Len);
+    CHECK(JS::FindSmallestEncoding(utf8Chars) == JS::SmallestEncoding::UTF16);
+    bool allocatedExternal = false;
+    JS::Rooted<JSString*> str(
+        cx, JS_NewMaybeExternalStringUTF8(cx, utf8Chars, &simpleCallback,
+                                          &allocatedExternal));
+    CHECK(str);
+    CHECK(!allocatedExternal);
+
+    const JSExternalStringCallbacks* callbacks = nullptr;
+    const JS::Latin1Char* chars = nullptr;
+    CHECK(!JS::IsExternalStringLatin1(str, &callbacks, &chars));
+    CHECK(!callbacks);
+    CHECK(!chars);
+
+    CHECK(!StringHasLatin1Chars(str));
+
+    JS::AutoAssertNoGC nogc(cx);
+    size_t length;
+    const char16_t* chars16 = nullptr;
+    chars16 = JS_GetTwoByteStringCharsAndLength(cx, nogc, str, &length);
+    CHECK(length == utf16Len);
+    CHECK(memcmp(chars16, utf16, length * sizeof(char16_t)) == 0);
+  }
+
+  return true;
+}
+END_TEST(testExternalStringsUTF8)