1 files changed, 146 insertions, 0 deletions
diff --git a/intl/lwbrk/nsUniscribeBreaker.cpp b/intl/lwbrk/nsUniscribeBreaker.cpp
new file mode 100644
index 0000000000..fcd1e282e1
--- /dev/null
+++ b/intl/lwbrk/nsUniscribeBreaker.cpp
@@ -0,0 +1,146 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsComplexBreaker.h"
+
+#include <windows.h>
+
+#include <usp10.h>
+
+#include "nsUTF8Utils.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+#if defined(MOZ_SANDBOX)
+#  include "mozilla/WindowsProcessMitigations.h"
+#  include "mozilla/SandboxSettings.h"
+#  include "mozilla/sandboxTarget.h"
+#  include "nsXULAppAPI.h"
+
+#  if defined(MOZ_DEBUG)
+#    include "mozilla/StaticPrefs_intl.h"
+#  endif
+#endif
+
+using namespace mozilla;
+
+#if defined(MOZ_SANDBOX)
+static bool UseBrokeredLineBreaking() {
+  // If win32k lockdown is enabled we can't use Uniscribe in this process. Also
+  // if the sandbox is above a certain level we can't load the required DLLs
+  // without other intervention. Given that it looks like we are likely to have
+  // win32k lockdown enabled first, using the brokered call for people testing
+  // this case also makes most sense.
+  static bool sUseBrokeredLineBreaking =
+      IsWin32kLockedDown() ||
+      (XRE_IsContentProcess() && GetEffectiveContentSandboxLevel() >= 20);
+
+  return sUseBrokeredLineBreaking;
+}
+#endif
+
+void NS_GetComplexLineBreaks(const char16_t* aText, uint32_t aLength,
+                             uint8_t* aBreakBefore) {
+  NS_ASSERTION(aText, "aText shouldn't be null");
+
+#if defined(MOZ_SANDBOX)
+  if (UseBrokeredLineBreaking()) {
+    // We can't use Uniscribe, so use a brokered call. Use of Uniscribe will be
+    // replaced in bug 1684927.
+    char16ptr_t text = aText;
+    if (!SandboxTarget::Instance()->GetComplexLineBreaks(text, aLength,
+                                                         aBreakBefore)) {
+      NS_WARNING("Brokered line break failed, breaks might be incorrect.");
+    }
+
+    return;
+  }
+#endif
+
+  int outItems = 0;
+  HRESULT result;
+  AutoTArray<SCRIPT_ITEM, 64> items;
+  char16ptr_t text = aText;
+
+  memset(aBreakBefore, false, aLength);
+
+  items.AppendElements(64);
+
+  do {
+    result = ScriptItemize(text, aLength, items.Length(), nullptr, nullptr,
+                           items.Elements(), &outItems);
+
+    if (result == E_OUTOFMEMORY) {
+      // XXX(Bug 1631371) Check if this should use a fallible operation as it
+      // pretended earlier.
+      items.AppendElements(items.Length());
+    }
+  } while (result == E_OUTOFMEMORY);
+
+  for (int iItem = 0; iItem < outItems; ++iItem) {
+    uint32_t endOffset =
+        (iItem + 1 == outItems ? aLength : items[iItem + 1].iCharPos);
+    uint32_t startOffset = items[iItem].iCharPos;
+    AutoTArray<SCRIPT_LOGATTR, 64> sla;
+
+    // XXX(Bug 1631371) Check if this should use a fallible operation as it
+    // pretended earlier.
+    sla.AppendElements(endOffset - startOffset);
+
+    if (ScriptBreak(text + startOffset, endOffset - startOffset,
+                    &items[iItem].a, sla.Elements()) < 0)
+      return;
+
+    // We don't want to set a potential break position at the start of text;
+    // that's the responsibility of a higher level.
+    for (uint32_t j = startOffset ? 0 : 1; j + startOffset < endOffset; ++j) {
+      aBreakBefore[j + startOffset] = sla[j].fSoftBreak;
+    }
+  }
+
+#if defined(MOZ_DEBUG) && defined(MOZ_SANDBOX)
+  // When tests are enabled and pref is set, we compare the line breaks returned
+  // from the Uniscribe breaker in the content process, with the ones returned
+  // from the brokered call to the parent. If they differ we crash so we can
+  // test using a crashtest.
+  if (!StaticPrefs::intl_compare_against_brokered_complex_line_breaks() ||
+      !XRE_IsContentProcess()) {
+    return;
+  }
+
+  nsTArray<uint8_t> brokeredBreaks(aLength);
+  brokeredBreaks.AppendElements(aLength);
+  if (!SandboxTarget::Instance()->GetComplexLineBreaks(
+          text, aLength, brokeredBreaks.Elements())) {
+    MOZ_CRASH("Brokered GetComplexLineBreaks failed.");
+  }
+
+  bool mismatch = false;
+  for (uint32_t i = 0; i < aLength; ++i) {
+    if (aBreakBefore[i] != brokeredBreaks[i]) {
+      mismatch = true;
+      break;
+    }
+  }
+
+  if (mismatch) {
+    // The logging here doesn't handle surrogates, but we only have tests using
+    // Thai currently, which is BMP-only.
+    printf_stderr("uniscribe: ");
+    for (uint32_t i = 0; i < aLength; ++i) {
+      if (aBreakBefore[i]) printf_stderr("#");
+      printf_stderr("%s", NS_ConvertUTF16toUTF8(aText + i, 1).get());
+    }
+    printf_stderr("\n");
+    printf_stderr("brokered : ");
+    for (uint32_t i = 0; i < aLength; ++i) {
+      if (brokeredBreaks[i]) printf_stderr("#");
+      printf_stderr("%s", NS_ConvertUTF16toUTF8(aText + i, 1).get());
+    }
+    printf_stderr("\n");
+    MOZ_CRASH("Brokered breaks did not match.");
+  }
+#endif
+}