import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

memory/replace/logalloc/FdPrintf.cpp

@@ -0,0 +1,132 @@
+/* -*- 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/. */
+
+#include <cstdarg>
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <unistd.h>
+#endif
+#include <cstring>
+#include "mozilla/Assertions.h"
+#include "mozilla/Unused.h"
+
+/* Template class allowing a limited number of increments on a value */
+template <typename T>
+class CheckedIncrement
+{
+public:
+  CheckedIncrement(T aValue, size_t aMaxIncrement)
+    : mValue(aValue), mMaxIncrement(aMaxIncrement)
+  {}
+
+  T operator ++(int)
+  {
+    if (!mMaxIncrement) {
+      MOZ_CRASH("overflow detected");
+    }
+    mMaxIncrement--;
+    return mValue++;
+  }
+
+  T& operator ++()
+  {
+    (*this)++;
+    return mValue;
+  }
+
+  operator T() { return mValue; }
+
+private:
+  T mValue;
+  size_t mMaxIncrement;
+};
+
+void
+FdPrintf(intptr_t aFd, const char* aFormat, ...)
+{
+  if (aFd == 0) {
+    return;
+  }
+  char buf[256];
+  CheckedIncrement<char*> b(buf, sizeof(buf));
+  CheckedIncrement<const char*> f(aFormat, strlen(aFormat) + 1);
+  va_list ap;
+  va_start(ap, aFormat);
+  while (true) {
+    switch (*f) {
+      case '\0':
+        goto out;
+
+      case '%':
+        switch (*++f) {
+          case 'z': {
+            if (*(++f) == 'u') {
+              size_t i = va_arg(ap, size_t);
+              size_t x = 1;
+              // Compute the number of digits.
+              while (x <= i / 10) {
+                x *= 10;
+              }
+              // Write the digits into the buffer.
+              do {
+                *(b++) = "0123456789"[(i / x) % 10];
+                x /= 10;
+              } while (x > 0);
+            } else {
+              // Write out the format specifier if it's unknown.
+              *(b++) = '%';
+              *(b++) = 'z';
+              *(b++) = *f;
+            }
+            break;
+          }
+
+          case 'p': {
+            intptr_t ptr = va_arg(ap, intptr_t);
+            *(b++) = '0';
+            *(b++) = 'x';
+            int x = sizeof(intptr_t) * 8;
+            bool wrote_msb = false;
+            do {
+              x -= 4;
+              size_t hex_digit = ptr >> x & 0xf;
+              if (hex_digit || wrote_msb) {
+                *(b++) = "0123456789abcdef"[hex_digit];
+                wrote_msb = true;
+              }
+            } while (x > 0);
+            if (!wrote_msb) {
+              *(b++) = '0';
+            }
+            break;
+          }
+
+          default:
+            // Write out the format specifier if it's unknown.
+            *(b++) = '%';
+            *(b++) = *f;
+            break;
+        }
+        break;
+
+      default:
+        *(b++) = *f;
+        break;
+    }
+    f++;
+  }
+out:
+#ifdef _WIN32
+  // See comment in FdPrintf.h as to why WriteFile is used.
+  DWORD written;
+  WriteFile(reinterpret_cast<HANDLE>(aFd), buf, b - buf, &written, nullptr);
+#else
+  MOZ_UNUSED(write(aFd, buf, b - buf));
+#endif
+  va_end(ap);
+}