Add Read/WriteSizeT() functions to the pickle layer, plus one consumer.

This eliminates the need for callers to do explicit conversions, and also
ensures callers don't try to implement pickling of a size_t using a 32-bit type,
leading to truncation on 64-bit targets.  The pickle layer will ensure 64-bit
types are always used.

I'll be changing other callsites to use this in future patches.

BUG=none
TEST=none

Review URL: https://codereview.chromium.org/601563003

Cr-Commit-Position: refs/heads/master@{#297774}

base/metrics/histogram.cc

@@ -37,13 +37,13 @@ bool ReadHistogramArguments(PickleIterator* iter,
                             int* flags,
                             int* declared_min,
                             int* declared_max,
-                            uint64* bucket_count,
+                            size_t* bucket_count,
                             uint32* range_checksum) {
   if (!iter->ReadString(histogram_name) ||
       !iter->ReadInt(flags) ||
       !iter->ReadInt(declared_min) ||
       !iter->ReadInt(declared_max) ||
-      !iter->ReadUInt64(bucket_count) ||
+      !iter->ReadSizeT(bucket_count) ||
       !iter->ReadUInt32(range_checksum)) {
     DLOG(ERROR) << "Pickle error decoding Histogram: " << *histogram_name;
     return false;
@@ -297,7 +297,7 @@ bool Histogram::SerializeInfoImpl(Pickle* pickle) const {
       pickle->WriteInt(flags()) &&
       pickle->WriteInt(declared_min()) &&
       pickle->WriteInt(declared_max()) &&
-      pickle->WriteUInt64(bucket_count()) &&
+      pickle->WriteSizeT(bucket_count()) &&
       pickle->WriteUInt32(bucket_ranges()->checksum());
 }
 
@@ -347,7 +347,7 @@ HistogramBase* Histogram::DeserializeInfoImpl(PickleIterator* iter) {
   int flags;
   int declared_min;
   int declared_max;
-  uint64 bucket_count;
+  size_t bucket_count;
   uint32 range_checksum;
 
   if (!ReadHistogramArguments(iter, &histogram_name, &flags, &declared_min,
@@ -636,7 +636,7 @@ HistogramBase* LinearHistogram::DeserializeInfoImpl(PickleIterator* iter) {
   int flags;
   int declared_min;
   int declared_max;
-  uint64 bucket_count;
+  size_t bucket_count;
   uint32 range_checksum;
 
   if (!ReadHistogramArguments(iter, &histogram_name, &flags, &declared_min,
@@ -691,7 +691,7 @@ HistogramBase* BooleanHistogram::DeserializeInfoImpl(PickleIterator* iter) {
   int flags;
   int declared_min;
   int declared_max;
-  uint64 bucket_count;
+  size_t bucket_count;
   uint32 range_checksum;
 
   if (!ReadHistogramArguments(iter, &histogram_name, &flags, &declared_min,
@@ -786,7 +786,7 @@ HistogramBase* CustomHistogram::DeserializeInfoImpl(PickleIterator* iter) {
   int flags;
   int declared_min;
   int declared_max;
-  uint64 bucket_count;
+  size_t bucket_count;
   uint32 range_checksum;
 
   if (!ReadHistogramArguments(iter, &histogram_name, &flags, &declared_min,

base/pickle.cc

@@ -106,6 +106,16 @@ bool PickleIterator::ReadUInt64(uint64* result) {
   return ReadBuiltinType(result);
 }
 
+bool PickleIterator::ReadSizeT(size_t* result) {
+  // Always read size_t as a 64-bit value to ensure compatibility between 32-bit
+  // and 64-bit processes.
+  uint64 result_uint64 = 0;
+  bool success = ReadBuiltinType(&result_uint64);
+  *result = static_cast<size_t>(result_uint64);
+  // Fail if the cast above truncates the value.
+  return success && (*result == result_uint64);
+}
+
 bool PickleIterator::ReadFloat(float* result) {
   // crbug.com/315213
   // The source data may not be properly aligned, and unaligned float reads

base/pickle.h

@@ -35,6 +35,7 @@ class BASE_EXPORT PickleIterator {
   bool ReadUInt32(uint32* result) WARN_UNUSED_RESULT;
   bool ReadInt64(int64* result) WARN_UNUSED_RESULT;
   bool ReadUInt64(uint64* result) WARN_UNUSED_RESULT;
+  bool ReadSizeT(size_t* result) WARN_UNUSED_RESULT;
   bool ReadFloat(float* result) WARN_UNUSED_RESULT;
   bool ReadDouble(double* result) WARN_UNUSED_RESULT;
   bool ReadString(std::string* result) WARN_UNUSED_RESULT;
@@ -172,6 +173,10 @@ class BASE_EXPORT Pickle {
                   uint64* result) const WARN_UNUSED_RESULT {
     return iter->ReadUInt64(result);
   }
+  bool ReadSizeT(PickleIterator* iter,
+                 size_t* result) const WARN_UNUSED_RESULT {
+    return iter->ReadSizeT(result);
+  }
   bool ReadFloat(PickleIterator* iter,
                  float* result) const WARN_UNUSED_RESULT {
     return iter->ReadFloat(result);
@@ -248,6 +253,11 @@ class BASE_EXPORT Pickle {
   bool WriteUInt64(uint64 value) {
     return WritePOD(value);
   }
+  bool WriteSizeT(size_t value) {
+    // Always write size_t as a 64-bit value to ensure compatibility between
+    // 32-bit and 64-bit processes.
+    return WritePOD(static_cast<uint64>(value));
+  }
   bool WriteFloat(float value) {
     return WritePOD(value);
   }

base/pickle_unittest.cc

@@ -8,6 +8,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/pickle.h"
 #include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // Remove when this file is in the base namespace.
@@ -15,43 +16,61 @@ using base::string16;
 
 namespace {
 
-const int testint = 2093847192;
-const std::string teststr("Hello world");  // note non-aligned string length
-const std::wstring testwstr(L"Hello, world");
-const char testdata[] = "AAA\0BBB\0";
-const int testdatalen = arraysize(testdata) - 1;
 const bool testbool1 = false;
 const bool testbool2 = true;
+const int testint = 2093847192;
+const long testlong = 1093847192;
 const uint16 testuint16 = 32123;
+const uint32 testuint32 = 1593847192;
+const int64 testint64 = -0x7E8CA9253104BDFCLL;
+const uint64 testuint64 = 0xCE8CA9253104BDF7ULL;
+const size_t testsizet = 0xFEDC7654;
 const float testfloat = 3.1415926935f;
 const double testdouble = 2.71828182845904523;
+const std::string teststring("Hello world");  // note non-aligned string length
+const std::wstring testwstring(L"Hello, world");
+const base::string16 teststring16(base::ASCIIToUTF16("Hello, world"));
+const char testdata[] = "AAA\0BBB\0";
+const int testdatalen = arraysize(testdata) - 1;
 
 // checks that the result
 void VerifyResult(const Pickle& pickle) {
   PickleIterator iter(pickle);
 
-  int outint;
-  EXPECT_TRUE(pickle.ReadInt(&iter, &outint));
-  EXPECT_EQ(testint, outint);
-
-  std::string outstr;
-  EXPECT_TRUE(pickle.ReadString(&iter, &outstr));
-  EXPECT_EQ(teststr, outstr);
-
-  std::wstring outwstr;
-  EXPECT_TRUE(pickle.ReadWString(&iter, &outwstr));
-  EXPECT_EQ(testwstr, outwstr);
-
   bool outbool;
   EXPECT_TRUE(pickle.ReadBool(&iter, &outbool));
   EXPECT_FALSE(outbool);
   EXPECT_TRUE(pickle.ReadBool(&iter, &outbool));
   EXPECT_TRUE(outbool);
 
+  int outint;
+  EXPECT_TRUE(pickle.ReadInt(&iter, &outint));
+  EXPECT_EQ(testint, outint);
+
+  long outlong;
+  EXPECT_TRUE(pickle.ReadLong(&iter, &outlong));
+  EXPECT_EQ(testlong, outlong);
+
   uint16 outuint16;
   EXPECT_TRUE(pickle.ReadUInt16(&iter, &outuint16));
   EXPECT_EQ(testuint16, outuint16);
 
+  uint32 outuint32;
+  EXPECT_TRUE(pickle.ReadUInt32(&iter, &outuint32));
+  EXPECT_EQ(testuint32, outuint32);
+
+  int64 outint64;
+  EXPECT_TRUE(pickle.ReadInt64(&iter, &outint64));
+  EXPECT_EQ(testint64, outint64);
+
+  uint64 outuint64;
+  EXPECT_TRUE(pickle.ReadUInt64(&iter, &outuint64));
+  EXPECT_EQ(testuint64, outuint64);
+
+  size_t outsizet;
+  EXPECT_TRUE(pickle.ReadSizeT(&iter, &outsizet));
+  EXPECT_EQ(testsizet, outsizet);
+
   float outfloat;
   EXPECT_TRUE(pickle.ReadFloat(&iter, &outfloat));
   EXPECT_EQ(testfloat, outfloat);
@@ -60,6 +79,18 @@ void VerifyResult(const Pickle& pickle) {
   EXPECT_TRUE(pickle.ReadDouble(&iter, &outdouble));
   EXPECT_EQ(testdouble, outdouble);
 
+  std::string outstring;
+  EXPECT_TRUE(pickle.ReadString(&iter, &outstring));
+  EXPECT_EQ(teststring, outstring);
+
+  std::wstring outwstring;
+  EXPECT_TRUE(pickle.ReadWString(&iter, &outwstring));
+  EXPECT_EQ(testwstring, outwstring);
+
+  base::string16 outstring16;
+  EXPECT_TRUE(pickle.ReadString16(&iter, &outstring16));
+  EXPECT_EQ(teststring16, outstring16);
+
   const char* outdata;
   int outdatalen;
   EXPECT_TRUE(pickle.ReadData(&iter, &outdata, &outdatalen));
@@ -75,14 +106,21 @@ void VerifyResult(const Pickle& pickle) {
 TEST(PickleTest, EncodeDecode) {
   Pickle pickle;
 
-  EXPECT_TRUE(pickle.WriteInt(testint));
-  EXPECT_TRUE(pickle.WriteString(teststr));
-  EXPECT_TRUE(pickle.WriteWString(testwstr));
   EXPECT_TRUE(pickle.WriteBool(testbool1));
   EXPECT_TRUE(pickle.WriteBool(testbool2));
+  EXPECT_TRUE(pickle.WriteInt(testint));
+  EXPECT_TRUE(
+      pickle.WriteLongUsingDangerousNonPortableLessPersistableForm(testlong));
   EXPECT_TRUE(pickle.WriteUInt16(testuint16));
+  EXPECT_TRUE(pickle.WriteUInt32(testuint32));
+  EXPECT_TRUE(pickle.WriteInt64(testint64));
+  EXPECT_TRUE(pickle.WriteUInt64(testuint64));
+  EXPECT_TRUE(pickle.WriteSizeT(testsizet));
   EXPECT_TRUE(pickle.WriteFloat(testfloat));
   EXPECT_TRUE(pickle.WriteDouble(testdouble));
+  EXPECT_TRUE(pickle.WriteString(teststring));
+  EXPECT_TRUE(pickle.WriteWString(testwstring));
+  EXPECT_TRUE(pickle.WriteString16(teststring16));
   EXPECT_TRUE(pickle.WriteData(testdata, testdatalen));
   VerifyResult(pickle);
 
@@ -96,6 +134,27 @@ TEST(PickleTest, EncodeDecode) {
   VerifyResult(pickle3);
 }
 
+// Tests that reading/writing a size_t works correctly when the source process
+// is 64-bit.  We rely on having both 32- and 64-bit trybots to validate both
+// arms of the conditional in this test.
+TEST(PickleTest, SizeTFrom64Bit) {
+  Pickle pickle;
+  // Under the hood size_t is always written as a 64-bit value, so simulate a
+  // 64-bit size_t even on 32-bit architectures by explicitly writing a uint64.
+  EXPECT_TRUE(pickle.WriteUInt64(testuint64));
+
+  PickleIterator iter(pickle);
+  size_t outsizet;
+  if (sizeof(size_t) < sizeof(uint64)) {
+    // ReadSizeT() should return false when the original written value can't be
+    // represented as a size_t.
+    EXPECT_FALSE(pickle.ReadSizeT(&iter, &outsizet));
+  } else {
+    EXPECT_TRUE(pickle.ReadSizeT(&iter, &outsizet));
+    EXPECT_EQ(testuint64, outsizet);
+  }
+}
+
 // Tests that we can handle really small buffers.
 TEST(PickleTest, SmallBuffer) {
   scoped_ptr<char[]> buffer(new char[1]);