Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/mfbt/DbgMacro.h b/mfbt/DbgMacro.h
new file mode 100644
index 0000000000..3247b993c0
--- /dev/null
+++ b/mfbt/DbgMacro.h
@@ -0,0 +1,206 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_DbgMacro_h
+#define mozilla_DbgMacro_h
+
+/* a MOZ_DBG macro that outputs a wrapped value to stderr then returns it */
+
+#include "mozilla/MacroForEach.h"
+#include "mozilla/Span.h"
+
+#include <stdio.h>
+#include <sstream>
+
+template <typename T>
+class nsTSubstring;
+
+#ifdef ANDROID
+#  include <android/log.h>
+#endif
+
+namespace mozilla {
+
+namespace detail {
+
+// Predicate to check whether T can be inserted into an ostream.
+template <typename T, typename = decltype(std::declval<std::ostream&>()
+                                          << std::declval<T>())>
+std::true_type supports_os_test(const T&);
+std::false_type supports_os_test(...);
+
+template <typename T>
+using supports_os = decltype(supports_os_test(std::declval<T>()));
+
+}  // namespace detail
+
+// Helper function to write a value to an ostream.
+//
+// This handles pointer values where the type being pointed to supports being
+// inserted into an ostream, and we write out the value being pointed to in
+// addition to the pointer value.
+template <typename T>
+auto DebugValue(std::ostream& aOut, T* aValue)
+    -> std::enable_if_t<mozilla::detail::supports_os<T>::value, std::ostream&> {
+  if (aValue) {
+    aOut << *aValue << " @ " << aValue;
+  } else {
+    aOut << "null";
+  }
+  return aOut;
+}
+
+// Helper function to write a value to an ostream.
+//
+// This handles all pointer types that cannot be dereferenced and inserted into
+// an ostream.
+template <typename T>
+auto DebugValue(std::ostream& aOut, T* aValue)
+    -> std::enable_if_t<!mozilla::detail::supports_os<T>::value,
+                        std::ostream&> {
+  return aOut << aValue;
+}
+
+// Helper function to write a value to an ostream.
+//
+// This handles XPCOM string types.
+template <typename T>
+auto DebugValue(std::ostream& aOut, const T& aValue)
+    -> std::enable_if_t<std::is_base_of<nsTSubstring<char>, T>::value ||
+                            std::is_base_of<nsTSubstring<char16_t>, T>::value,
+                        std::ostream&> {
+  return aOut << '"' << aValue << '"';
+}
+
+// Helper function to write a value to an ostream.
+//
+// This handles all other types.
+template <typename T>
+auto DebugValue(std::ostream& aOut, const T& aValue)
+    -> std::enable_if_t<!std::is_base_of<nsTSubstring<char>, T>::value &&
+                            !std::is_base_of<nsTSubstring<char16_t>, T>::value,
+                        std::ostream&> {
+  return aOut << aValue;
+}
+
+namespace detail {
+
+// Helper function template for MOZ_DBG.
+template <typename T>
+auto&& MozDbg(const char* aFile, int aLine, const char* aExpression,
+              T&& aValue) {
+  std::ostringstream s;
+  s << "[MozDbg] [" << aFile << ':' << aLine << "] " << aExpression << " = ";
+  mozilla::DebugValue(s, std::forward<T>(aValue));
+  s << '\n';
+#ifdef ANDROID
+  __android_log_print(ANDROID_LOG_INFO, "Gecko", "%s", s.str().c_str());
+#else
+  fputs(s.str().c_str(), stderr);
+#endif
+  return std::forward<T>(aValue);
+}
+
+}  // namespace detail
+
+}  // namespace mozilla
+
+template <class ElementType, size_t Extent>
+std::ostream& operator<<(std::ostream& aOut,
+                         const mozilla::Span<ElementType, Extent>& aSpan) {
+  aOut << '[';
+  if (!aSpan.IsEmpty()) {
+    aOut << aSpan[0];
+    for (size_t i = 1; i < aSpan.Length(); ++i) {
+      aOut << ", " << aSpan[i];
+    }
+  }
+  return aOut << ']';
+}
+
+// Don't define this for char[], since operator<<(ostream&, char*) is already
+// defined.
+template <typename T, size_t N,
+          typename = std::enable_if_t<!std::is_same<T, char>::value>>
+std::ostream& operator<<(std::ostream& aOut, const T (&aArray)[N]) {
+  return aOut << mozilla::Span(aArray);
+}
+
+// MOZ_DBG is a macro like the Rust dbg!() macro -- it will print out the
+// expression passed to it to stderr and then return the value.  It is not
+// available in MOZILLA_OFFICIAL builds, so you shouldn't land any uses of it in
+// the tree.
+//
+// It should work for any type T that has an operator<<(std::ostream&, const T&)
+// defined for it.
+//
+// Note 1: Using MOZ_DBG may cause copies to be made of temporary values:
+//
+//   struct A {
+//     A(int);
+//     A(const A&);
+//
+//     int x;
+//   };
+//
+//   void f(A);
+//
+//   f(A{1});  // may (and, in C++17, will) elide the creation of a temporary
+//             // for A{1} and instead initialize the function argument
+//             // directly using the A(int) constructor
+//
+//   f(MOZ_DBG(A{1}));  // will create and return a temporary for A{1}, which
+//                      // then will be passed to the A(const A&) copy
+//                      // constructor to initialize f's argument
+//
+// Note 2: MOZ_DBG cannot be used to wrap a prvalue that is being used to
+// initialize an object if its type has no move constructor:
+//
+//   struct B {
+//     B() = default;
+//     B(B&&) = delete;
+//   };
+//
+//   B b1 = B();  // fine, initializes b1 directly
+//
+//   B b2 = MOZ_DBG(B());  // compile error: MOZ_DBG needs to materialize a
+//                         // temporary for B() so it can be passed to
+//                         // operator<<, but that temporary is returned from
+//                         // MOZ_DBG as an rvalue reference and so wants to
+//                         // invoke B's move constructor to initialize b2
+#ifndef MOZILLA_OFFICIAL
+#  define MOZ_DBG(...) \
+    mozilla::detail::MozDbg(__FILE__, __LINE__, #__VA_ARGS__, __VA_ARGS__)
+#endif
+
+// Helper macro for MOZ_DEFINE_DBG.
+#define MOZ_DBG_FIELD(name_) << #name_ << " = " << aValue.name_
+
+// Macro to define an operator<<(ostream&) for a struct or class that displays
+// the type name and the values of the specified member variables.  Must be
+// called inside the struct or class.
+//
+// For example:
+//
+//   struct Point {
+//     float x;
+//     float y;
+//
+//     MOZ_DEFINE_DBG(Point, x, y)
+//   };
+//
+// generates an operator<< that outputs strings like
+// "Point { x = 1.0, y = 2.0 }".
+#define MOZ_DEFINE_DBG(type_, ...)                                           \
+  friend std::ostream& operator<<(std::ostream& aOut, const type_& aValue) { \
+    return aOut << #type_                                                    \
+                << (MOZ_ARG_COUNT(__VA_ARGS__) == 0 ? "" : " { ")            \
+                       MOZ_FOR_EACH_SEPARATED(MOZ_DBG_FIELD, (<< ", "), (),  \
+                                              (__VA_ARGS__))                 \
+                << (MOZ_ARG_COUNT(__VA_ARGS__) == 0 ? "" : " }");            \
+  }
+
+#endif  // mozilla_DbgMacro_h