From 43a97878ce14b72f0981164f87f2e35e14151312 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 11:22:09 +0200 Subject: Adding upstream version 110.0.1. Signed-off-by: Daniel Baumann --- .../baseprofiler/public/BaseProfileJSONWriter.h | 600 +++++++++++++++++++++ 1 file changed, 600 insertions(+) create mode 100644 mozglue/baseprofiler/public/BaseProfileJSONWriter.h (limited to 'mozglue/baseprofiler/public/BaseProfileJSONWriter.h') diff --git a/mozglue/baseprofiler/public/BaseProfileJSONWriter.h b/mozglue/baseprofiler/public/BaseProfileJSONWriter.h new file mode 100644 index 0000000000..00a2926366 --- /dev/null +++ b/mozglue/baseprofiler/public/BaseProfileJSONWriter.h @@ -0,0 +1,600 @@ +/* -*- 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/. */ + +#ifndef BASEPROFILEJSONWRITER_H +#define BASEPROFILEJSONWRITER_H + +#include "mozilla/FailureLatch.h" +#include "mozilla/HashFunctions.h" +#include "mozilla/HashTable.h" +#include "mozilla/JSONWriter.h" +#include "mozilla/Maybe.h" +#include "mozilla/NotNull.h" +#include "mozilla/ProgressLogger.h" +#include "mozilla/TimeStamp.h" +#include "mozilla/UniquePtrExtensions.h" + +#include +#include +#include + +namespace mozilla { +namespace baseprofiler { + +class SpliceableJSONWriter; + +// On average, profile JSONs are large enough such that we want to avoid +// reallocating its buffer when expanding. Additionally, the contents of the +// profile are not accessed until the profile is entirely written. For these +// reasons we use a chunked writer that keeps an array of chunks, which is +// concatenated together after writing is finished. +class ChunkedJSONWriteFunc final : public JSONWriteFunc, public FailureLatch { + public: + friend class SpliceableJSONWriter; + + explicit ChunkedJSONWriteFunc(FailureLatch& aFailureLatch) + : mFailureLatch(WrapNotNullUnchecked(&aFailureLatch)) { + (void)AllocChunk(kChunkSize); + } + + [[nodiscard]] bool IsEmpty() const { + MOZ_ASSERT_IF(!mChunkPtr, !mChunkEnd && mChunkList.length() == 0 && + mChunkLengths.length() == 0); + return !mChunkPtr; + } + + // Length of data written so far, excluding null terminator. + [[nodiscard]] size_t Length() const { + MOZ_ASSERT(mChunkLengths.length() == mChunkList.length()); + size_t totalLen = 0; + for (size_t i = 0; i < mChunkLengths.length(); i++) { + MOZ_ASSERT(strlen(mChunkList[i].get()) == mChunkLengths[i]); + totalLen += mChunkLengths[i]; + } + return totalLen; + } + + void Write(const Span& aStr) final { + if (Failed()) { + return; + } + + MOZ_ASSERT(mChunkPtr >= mChunkList.back().get() && mChunkPtr <= mChunkEnd); + MOZ_ASSERT(mChunkEnd >= mChunkList.back().get() + mChunkLengths.back()); + MOZ_ASSERT(*mChunkPtr == '\0'); + + // Most strings to be written are small, but subprocess profiles (e.g., + // from the content process in e10s) may be huge. If the string is larger + // than a chunk, allocate its own chunk. + char* newPtr; + if (aStr.size() >= kChunkSize) { + if (!AllocChunk(aStr.size() + 1)) { + return; + } + newPtr = mChunkPtr + aStr.size(); + } else { + newPtr = mChunkPtr + aStr.size(); + if (newPtr >= mChunkEnd) { + if (!AllocChunk(kChunkSize)) { + return; + } + newPtr = mChunkPtr + aStr.size(); + } + } + + memcpy(mChunkPtr, aStr.data(), aStr.size()); + *newPtr = '\0'; + mChunkPtr = newPtr; + mChunkLengths.back() += aStr.size(); + } + + [[nodiscard]] bool CopyDataIntoLazilyAllocatedBuffer( + const std::function& aAllocator) const { + // Request a buffer for the full content plus a null terminator. + if (Failed()) { + return false; + } + + char* ptr = aAllocator(Length() + 1); + + if (!ptr) { + // Failed to allocate memory. + return false; + } + + for (size_t i = 0; i < mChunkList.length(); i++) { + size_t len = mChunkLengths[i]; + memcpy(ptr, mChunkList[i].get(), len); + ptr += len; + } + *ptr = '\0'; + return true; + } + + [[nodiscard]] UniquePtr CopyData() const { + UniquePtr c; + if (!CopyDataIntoLazilyAllocatedBuffer([&](size_t allocationSize) { + c = MakeUnique(allocationSize); + return c.get(); + })) { + // Something went wrong, make sure the returned pointer is null even if + // the allocation happened. + c = nullptr; + } + return c; + } + + void Take(ChunkedJSONWriteFunc&& aOther) { + SetFailureFrom(aOther); + if (Failed()) { + return; + } + + for (size_t i = 0; i < aOther.mChunkList.length(); i++) { + MOZ_ALWAYS_TRUE(mChunkLengths.append(aOther.mChunkLengths[i])); + MOZ_ALWAYS_TRUE(mChunkList.append(std::move(aOther.mChunkList[i]))); + } + mChunkPtr = mChunkList.back().get() + mChunkLengths.back(); + mChunkEnd = mChunkPtr; + aOther.Clear(); + } + + FAILURELATCH_IMPL_PROXY(*mFailureLatch) + + // Change the failure latch to be used here, and if the previous latch was + // already in failure state, set that failure in the new latch. + // This allows using this WriteFunc in isolation, before attempting to bring + // it into another operation group with its own FailureLatch. + void ChangeFailureLatchAndForwardState(FailureLatch& aFailureLatch) { + aFailureLatch.SetFailureFrom(*this); + mFailureLatch = WrapNotNullUnchecked(&aFailureLatch); + } + + private: + void Clear() { + mChunkPtr = nullptr; + mChunkEnd = nullptr; + mChunkList.clear(); + mChunkLengths.clear(); + } + + void ClearAndSetFailure(std::string aFailure) { + Clear(); + SetFailure(std::move(aFailure)); + } + + [[nodiscard]] bool ClearAndSetFailureAndFalse(std::string aFailure) { + ClearAndSetFailure(std::move(aFailure)); + return false; + } + + [[nodiscard]] bool AllocChunk(size_t aChunkSize) { + if (Failed()) { + if (mChunkPtr) { + // FailureLatch is in failed state, but chunks have not been cleared yet + // (error must have happened elsewhere). + Clear(); + } + return false; + } + + MOZ_ASSERT(mChunkLengths.length() == mChunkList.length()); + UniquePtr newChunk = MakeUniqueFallible(aChunkSize); + if (!newChunk) { + return ClearAndSetFailureAndFalse( + "OOM in ChunkedJSONWriteFunc::AllocChunk allocating new chunk"); + } + mChunkPtr = newChunk.get(); + mChunkEnd = mChunkPtr + aChunkSize; + *mChunkPtr = '\0'; + if (!mChunkLengths.append(0)) { + return ClearAndSetFailureAndFalse( + "OOM in ChunkedJSONWriteFunc::AllocChunk appending length"); + } + if (!mChunkList.append(std::move(newChunk))) { + return ClearAndSetFailureAndFalse( + "OOM in ChunkedJSONWriteFunc::AllocChunk appending new chunk"); + } + return true; + } + + static const size_t kChunkSize = 4096 * 512; + + // Pointer for writing inside the current chunk. + // + // The current chunk is always at the back of mChunkList, i.e., + // mChunkList.back() <= mChunkPtr <= mChunkEnd. + char* mChunkPtr = nullptr; + + // Pointer to the end of the current chunk. + // + // The current chunk is always at the back of mChunkList, i.e., + // mChunkEnd >= mChunkList.back() + mChunkLengths.back(). + char* mChunkEnd = nullptr; + + // List of chunks and their lengths. + // + // For all i, the length of the string in mChunkList[i] is + // mChunkLengths[i]. + Vector> mChunkList; + Vector mChunkLengths; + + NotNull mFailureLatch; +}; + +struct OStreamJSONWriteFunc final : public JSONWriteFunc { + explicit OStreamJSONWriteFunc(std::ostream& aStream) : mStream(aStream) {} + + void Write(const Span& aStr) final { + std::string_view sv(aStr.data(), aStr.size()); + mStream << sv; + } + + std::ostream& mStream; +}; + +class UniqueJSONStrings; + +class SpliceableJSONWriter : public JSONWriter, public FailureLatch { + public: + SpliceableJSONWriter(JSONWriteFunc& aWriter, FailureLatch& aFailureLatch) + : JSONWriter(aWriter, JSONWriter::SingleLineStyle), + mFailureLatch(WrapNotNullUnchecked(&aFailureLatch)) {} + + SpliceableJSONWriter(UniquePtr aWriter, + FailureLatch& aFailureLatch) + : JSONWriter(std::move(aWriter), JSONWriter::SingleLineStyle), + mFailureLatch(WrapNotNullUnchecked(&aFailureLatch)) {} + + void StartBareList() { StartCollection(scEmptyString, scEmptyString); } + + void EndBareList() { EndCollection(scEmptyString); } + + // Output a time (int64_t given in nanoseconds) in milliseconds. trim zeroes. + // E.g.: 1'234'567'890 -> "1234.56789" + void TimeI64NsProperty(const Span& aMaybePropertyName, + int64_t aTime_ns) { + if (aTime_ns == 0) { + Scalar(aMaybePropertyName, MakeStringSpan("0")); + return; + } + + static constexpr int64_t million = 1'000'000; + const int64_t absNanos = std::abs(aTime_ns); + const int64_t integerMilliseconds = absNanos / million; + auto remainderNanoseconds = static_cast(absNanos % million); + + // Plenty enough to fit INT64_MIN (-9223372036854775808). + static constexpr size_t DIGITS_MAX = 23; + char buf[DIGITS_MAX + 1]; + int len = + snprintf(buf, DIGITS_MAX, (aTime_ns >= 0) ? "%" PRIu64 : "-%" PRIu64, + integerMilliseconds); + if (remainderNanoseconds != 0) { + buf[len++] = '.'; + // Output up to 6 fractional digits. Exit early if the rest would + // be trailing zeros. + uint32_t powerOfTen = static_cast(million / 10); + for (;;) { + auto digit = remainderNanoseconds / powerOfTen; + buf[len++] = '0' + static_cast(digit); + remainderNanoseconds %= powerOfTen; + if (remainderNanoseconds == 0) { + break; + } + powerOfTen /= 10; + if (powerOfTen == 0) { + break; + } + } + } + + Scalar(aMaybePropertyName, Span(buf, len)); + } + + // Output a (double) time in milliseconds, with at best nanosecond precision. + void TimeDoubleMsProperty(const Span& aMaybePropertyName, + double aTime_ms) { + const double dTime_ns = aTime_ms * 1'000'000.0; + // Make sure it's well within int64_t range. + // 2^63 nanoseconds is almost 300 years; these times are relative to + // firefox startup, this should be enough for most uses. + if (dTime_ns >= 0.0) { + MOZ_RELEASE_ASSERT(dTime_ns < double(INT64_MAX - 1)); + } else { + MOZ_RELEASE_ASSERT(dTime_ns > double(INT64_MIN + 2)); + } + // Round to nearest integer nanosecond. The conversion to integer truncates + // the fractional part, so first we need to push it 0.5 away from zero. + const int64_t iTime_ns = + (dTime_ns >= 0.0) ? int64_t(dTime_ns + 0.5) : int64_t(dTime_ns - 0.5); + TimeI64NsProperty(aMaybePropertyName, iTime_ns); + } + + // Output a (double) time in milliseconds, with at best nanosecond precision. + void TimeDoubleMsElement(double aTime_ms) { + TimeDoubleMsProperty(nullptr, aTime_ms); + } + + // This function must be used to correctly stream timestamps in profiles. + // Null timestamps don't output anything. + void TimeProperty(const Span& aMaybePropertyName, + const TimeStamp& aTime) { + if (!aTime.IsNull()) { + TimeDoubleMsProperty( + aMaybePropertyName, + (aTime - TimeStamp::ProcessCreation()).ToMilliseconds()); + } + } + + void NullElements(uint32_t aCount) { + for (uint32_t i = 0; i < aCount; i++) { + NullElement(); + } + } + + void Splice(const Span& aStr) { + Separator(); + WriteFunc().Write(aStr); + mNeedComma[mDepth] = true; + } + + void Splice(const char* aStr, size_t aLen) { + Separator(); + WriteFunc().Write(Span(aStr, aLen)); + mNeedComma[mDepth] = true; + } + + // Splice the given JSON directly in, without quoting. + void SplicedJSONProperty(const Span& aMaybePropertyName, + const Span& aJsonValue) { + Scalar(aMaybePropertyName, aJsonValue); + } + + void CopyAndSplice(const ChunkedJSONWriteFunc& aFunc) { + Separator(); + for (size_t i = 0; i < aFunc.mChunkList.length(); i++) { + WriteFunc().Write( + Span(aFunc.mChunkList[i].get(), aFunc.mChunkLengths[i])); + } + mNeedComma[mDepth] = true; + } + + // Takes the chunks from aFunc and write them. If move is not possible + // (e.g., using OStreamJSONWriteFunc), aFunc's chunks are copied and its + // storage cleared. + virtual void TakeAndSplice(ChunkedJSONWriteFunc&& aFunc) { + Separator(); + for (size_t i = 0; i < aFunc.mChunkList.length(); i++) { + WriteFunc().Write( + Span(aFunc.mChunkList[i].get(), aFunc.mChunkLengths[i])); + } + aFunc.mChunkPtr = nullptr; + aFunc.mChunkEnd = nullptr; + aFunc.mChunkList.clear(); + aFunc.mChunkLengths.clear(); + mNeedComma[mDepth] = true; + } + + // Set (or reset) the pointer to a UniqueJSONStrings. + void SetUniqueStrings(UniqueJSONStrings& aUniqueStrings) { + MOZ_RELEASE_ASSERT(!mUniqueStrings); + mUniqueStrings = &aUniqueStrings; + } + + // Set (or reset) the pointer to a UniqueJSONStrings. + void ResetUniqueStrings() { + MOZ_RELEASE_ASSERT(mUniqueStrings); + mUniqueStrings = nullptr; + } + + // Add `aStr` to the unique-strings list (if not already there), and write its + // index as a named object property. + inline void UniqueStringProperty(const Span& aName, + const Span& aStr); + + // Add `aStr` to the unique-strings list (if not already there), and write its + // index as an array element. + inline void UniqueStringElement(const Span& aStr); + + // THe following functions override JSONWriter functions non-virtually. The + // goal is to try and prevent calls that specify a style, which would be + // ignored anyway because the whole thing is single-lined. It's fine if some + // calls still make it through a `JSONWriter&`, no big deal. + void Start() { JSONWriter::Start(); } + void StartArrayProperty(const Span& aName) { + JSONWriter::StartArrayProperty(aName); + } + template + void StartArrayProperty(const char (&aName)[N]) { + JSONWriter::StartArrayProperty(Span(aName, N)); + } + void StartArrayElement() { JSONWriter::StartArrayElement(); } + void StartObjectProperty(const Span& aName) { + JSONWriter::StartObjectProperty(aName); + } + template + void StartObjectProperty(const char (&aName)[N]) { + JSONWriter::StartObjectProperty(Span(aName, N)); + } + void StartObjectElement() { JSONWriter::StartObjectElement(); } + + FAILURELATCH_IMPL_PROXY(*mFailureLatch) + + protected: + NotNull mFailureLatch; + + private: + UniqueJSONStrings* mUniqueStrings = nullptr; +}; + +class SpliceableChunkedJSONWriter final : public SpliceableJSONWriter { + public: + explicit SpliceableChunkedJSONWriter(FailureLatch& aFailureLatch) + : SpliceableJSONWriter(MakeUnique(aFailureLatch), + aFailureLatch) {} + + // Access the ChunkedJSONWriteFunc as reference-to-const, usually to copy data + // out. + const ChunkedJSONWriteFunc& ChunkedWriteFunc() const { + return ChunkedWriteFuncRef(); + } + + // Access the ChunkedJSONWriteFunc as rvalue-reference, usually to take its + // data out. This writer shouldn't be used anymore after this. + ChunkedJSONWriteFunc&& TakeChunkedWriteFunc() { + ChunkedJSONWriteFunc& ref = ChunkedWriteFuncRef(); +#ifdef DEBUG + mTaken = true; +#endif // + return std::move(ref); + } + + // Adopts the chunks from aFunc without copying. + void TakeAndSplice(ChunkedJSONWriteFunc&& aFunc) override { + MOZ_ASSERT(!mTaken); + Separator(); + ChunkedWriteFuncRef().Take(std::move(aFunc)); + mNeedComma[mDepth] = true; + } + + void ChangeFailureLatchAndForwardState(FailureLatch& aFailureLatch) { + mFailureLatch = WrapNotNullUnchecked(&aFailureLatch); + return ChunkedWriteFuncRef().ChangeFailureLatchAndForwardState( + aFailureLatch); + } + + private: + const ChunkedJSONWriteFunc& ChunkedWriteFuncRef() const { + MOZ_ASSERT(!mTaken); + // The WriteFunc was non-fallibly allocated as a ChunkedJSONWriteFunc in the + // only constructor above, so it's safe to cast to ChunkedJSONWriteFunc&. + return static_cast(WriteFunc()); + } + + ChunkedJSONWriteFunc& ChunkedWriteFuncRef() { + MOZ_ASSERT(!mTaken); + // The WriteFunc was non-fallibly allocated as a ChunkedJSONWriteFunc in the + // only constructor above, so it's safe to cast to ChunkedJSONWriteFunc&. + return static_cast(WriteFunc()); + } + +#ifdef DEBUG + bool mTaken = false; +#endif +}; + +class JSONSchemaWriter { + JSONWriter& mWriter; + uint32_t mIndex; + + public: + explicit JSONSchemaWriter(JSONWriter& aWriter) : mWriter(aWriter), mIndex(0) { + aWriter.StartObjectProperty("schema", + SpliceableJSONWriter::SingleLineStyle); + } + + void WriteField(const Span& aName) { + mWriter.IntProperty(aName, mIndex++); + } + + template + void WriteField(const char (&aName)[Np1]) { + WriteField(Span(aName, Np1 - 1)); + } + + ~JSONSchemaWriter() { mWriter.EndObject(); } +}; + +// This class helps create an indexed list of unique strings, and inserts the +// index as a JSON value. The collected list of unique strings can later be +// inserted as a JSON array. +// This can be useful for elements/properties with many repeated strings. +// +// With only JSONWriter w, +// `w.WriteElement("a"); w.WriteElement("b"); w.WriteElement("a");` +// when done inside a JSON array, will generate: +// `["a", "b", "c"]` +// +// With UniqueStrings u, +// `u.WriteElement(w, "a"); u.WriteElement(w, "b"); u.WriteElement(w, "a");` +// when done inside a JSON array, will generate: +// `[0, 1, 0]` +// and later, `u.SpliceStringTableElements(w)` (inside a JSON array), will +// output the corresponding indexed list of unique strings: +// `["a", "b"]` +class UniqueJSONStrings final : public FailureLatch { + public: + // Start an empty list of unique strings. + MFBT_API explicit UniqueJSONStrings(FailureLatch& aFailureLatch); + + // Start with a copy of the strings from another list. + MFBT_API UniqueJSONStrings(FailureLatch& aFailureLatch, + const UniqueJSONStrings& aOther, + ProgressLogger aProgressLogger); + + MFBT_API ~UniqueJSONStrings(); + + // Add `aStr` to the list (if not already there), and write its index as a + // named object property. + void WriteProperty(SpliceableJSONWriter& aWriter, + const Span& aName, + const Span& aStr) { + if (const Maybe maybeIndex = GetOrAddIndex(aStr); maybeIndex) { + aWriter.IntProperty(aName, *maybeIndex); + } else { + aWriter.SetFailureFrom(*this); + } + } + + // Add `aStr` to the list (if not already there), and write its index as an + // array element. + void WriteElement(SpliceableJSONWriter& aWriter, + const Span& aStr) { + if (const Maybe maybeIndex = GetOrAddIndex(aStr); maybeIndex) { + aWriter.IntElement(*maybeIndex); + } else if (!aWriter.Failed()) { + aWriter.SetFailureFrom(*this); + } + } + + // Splice all collected unique strings into an array. This should only be done + // once, and then this UniqueStrings shouldn't be used anymore. + MFBT_API void SpliceStringTableElements(SpliceableJSONWriter& aWriter); + + FAILURELATCH_IMPL_PROXY(mStringTableWriter) + + void ChangeFailureLatchAndForwardState(FailureLatch& aFailureLatch) { + mStringTableWriter.ChangeFailureLatchAndForwardState(aFailureLatch); + } + + private: + MFBT_API void ClearAndSetFailure(std::string aFailure); + + // If `aStr` is already listed, return its index. + // Otherwise add it to the list and return the new index. + MFBT_API Maybe GetOrAddIndex(const Span& aStr); + + SpliceableChunkedJSONWriter mStringTableWriter; + HashMap mStringHashToIndexMap; +}; + +void SpliceableJSONWriter::UniqueStringProperty(const Span& aName, + const Span& aStr) { + MOZ_RELEASE_ASSERT(mUniqueStrings); + mUniqueStrings->WriteProperty(*this, aName, aStr); +} + +// Add `aStr` to the list (if not already there), and write its index as an +// array element. +void SpliceableJSONWriter::UniqueStringElement(const Span& aStr) { + MOZ_RELEASE_ASSERT(mUniqueStrings); + mUniqueStrings->WriteElement(*this, aStr); +} + +} // namespace baseprofiler +} // namespace mozilla + +#endif // BASEPROFILEJSONWRITER_H -- cgit v1.2.3