Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

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

1 files changed, 457 insertions, 0 deletions

diff --git a/js/src/vm/Xdr.h b/js/src/vm/Xdr.h
new file mode 100644
index 0000000000..c37d94627a
--- /dev/null
+++ b/js/src/vm/Xdr.h
@@ -0,0 +1,457 @@
+/* -*- 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 vm_Xdr_h
+#define vm_Xdr_h
+
+#include "mozilla/Assertions.h"  // MOZ_ASSERT, MOZ_CRASH
+#include "mozilla/MaybeOneOf.h"  // mozilla::MaybeOneOf
+#include "mozilla/Result.h"      // mozilla::{Result, Ok, Err}, MOZ_TRY
+#include "mozilla/Utf8.h"        // mozilla::Utf8Unit
+
+#include <stddef.h>     // size_t
+#include <stdint.h>     // uint8_t, uint16_t, uint32_t, uint64_t
+#include <string.h>     // memcpy
+#include <type_traits>  // std::enable_if_t
+
+#include "js/AllocPolicy.h"  // ReportOutOfMemory
+#include "js/Transcoding.h"  // JS::TranscodeResult, JS::TranscodeBuffer, JS::TranscodeRange, IsTranscodingBytecodeAligned, IsTranscodingBytecodeOffsetAligned
+#include "js/TypeDecls.h"    // JS::Latin1Char
+#include "js/UniquePtr.h"    // UniquePtr
+#include "js/Utility.h"      // JS::FreePolicy
+
+struct JSContext;
+
+namespace js {
+
+enum XDRMode { XDR_ENCODE, XDR_DECODE };
+
+template <typename T>
+using XDRResultT = mozilla::Result<T, JS::TranscodeResult>;
+using XDRResult = XDRResultT<mozilla::Ok>;
+
+class XDRBufferBase {
+ public:
+  explicit XDRBufferBase(FrontendContext* fc, size_t cursor = 0)
+      : fc_(fc), cursor_(cursor) {}
+
+  FrontendContext* fc() const { return fc_; }
+
+  size_t cursor() const { return cursor_; }
+
+ protected:
+  FrontendContext* const fc_;
+  size_t cursor_;
+};
+
+template <XDRMode mode>
+class XDRBuffer;
+
+template <>
+class XDRBuffer<XDR_ENCODE> : public XDRBufferBase {
+ public:
+  XDRBuffer(FrontendContext* fc, JS::TranscodeBuffer& buffer, size_t cursor = 0)
+      : XDRBufferBase(fc, cursor), buffer_(buffer) {}
+
+  uint8_t* write(size_t n) {
+    MOZ_ASSERT(n != 0);
+    if (!buffer_.growByUninitialized(n)) {
+      ReportOutOfMemory(fc());
+      return nullptr;
+    }
+    uint8_t* ptr = &buffer_[cursor_];
+    cursor_ += n;
+    return ptr;
+  }
+
+  bool align32() {
+    size_t extra = cursor_ % 4;
+    if (extra) {
+      size_t padding = 4 - extra;
+      if (!buffer_.appendN(0, padding)) {
+        ReportOutOfMemory(fc());
+        return false;
+      }
+      cursor_ += padding;
+    }
+    return true;
+  }
+
+  bool isAligned32() { return cursor_ % 4 == 0; }
+
+  const uint8_t* read(size_t n) {
+    MOZ_CRASH("Should never read in encode mode");
+    return nullptr;
+  }
+
+  const uint8_t* peek(size_t n) {
+    MOZ_CRASH("Should never read in encode mode");
+    return nullptr;
+  }
+
+  uint8_t* bufferAt(size_t cursor) {
+    MOZ_ASSERT(cursor < buffer_.length());
+    return &buffer_[cursor];
+  }
+
+ private:
+  JS::TranscodeBuffer& buffer_;
+};
+
+template <>
+class XDRBuffer<XDR_DECODE> : public XDRBufferBase {
+ public:
+  XDRBuffer(FrontendContext* fc, const JS::TranscodeRange& range)
+      : XDRBufferBase(fc), buffer_(range) {}
+
+  // This isn't used by XDRStencilDecoder.
+  // Defined just for XDRState, shared with XDRStencilEncoder.
+  XDRBuffer(FrontendContext* fc, JS::TranscodeBuffer& buffer, size_t cursor = 0)
+      : XDRBufferBase(fc, cursor), buffer_(buffer.begin(), buffer.length()) {}
+
+  bool align32() {
+    size_t extra = cursor_ % 4;
+    if (extra) {
+      size_t padding = 4 - extra;
+      cursor_ += padding;
+
+      // Don't let buggy code read past our buffer
+      if (cursor_ > buffer_.length()) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  bool isAligned32() { return cursor_ % 4 == 0; }
+
+  const uint8_t* read(size_t n) {
+    MOZ_ASSERT(cursor_ < buffer_.length());
+    const uint8_t* ptr = &buffer_[cursor_];
+    cursor_ += n;
+
+    // Don't let buggy code read past our buffer
+    if (cursor_ > buffer_.length()) {
+      return nullptr;
+    }
+
+    return ptr;
+  }
+
+  const uint8_t* peek(size_t n) {
+    MOZ_ASSERT(cursor_ < buffer_.length());
+    const uint8_t* ptr = &buffer_[cursor_];
+
+    // Don't let buggy code read past our buffer
+    if (cursor_ + n > buffer_.length()) {
+      return nullptr;
+    }
+
+    return ptr;
+  }
+
+  uint8_t* write(size_t n) {
+    MOZ_CRASH("Should never write in decode mode");
+    return nullptr;
+  }
+
+ private:
+  const JS::TranscodeRange buffer_;
+};
+
+template <typename CharT>
+using XDRTranscodeString =
+    mozilla::MaybeOneOf<const CharT*, js::UniquePtr<CharT[], JS::FreePolicy>>;
+
+class XDRCoderBase {
+ private:
+#ifdef DEBUG
+  JS::TranscodeResult resultCode_;
+#endif
+
+ protected:
+  XDRCoderBase()
+#ifdef DEBUG
+      : resultCode_(JS::TranscodeResult::Ok)
+#endif
+  {
+  }
+
+ public:
+#ifdef DEBUG
+  // Record logical failures of XDR.
+  JS::TranscodeResult resultCode() const { return resultCode_; }
+  void setResultCode(JS::TranscodeResult code) {
+    MOZ_ASSERT(resultCode() == JS::TranscodeResult::Ok);
+    resultCode_ = code;
+  }
+  bool validateResultCode(FrontendContext* fc, JS::TranscodeResult code) const;
+#endif
+};
+
+/*
+ * XDR serialization state.  All data is encoded in native endian, except
+ * bytecode.
+ */
+template <XDRMode mode>
+class XDRState : public XDRCoderBase {
+ protected:
+  XDRBuffer<mode> mainBuf;
+  XDRBuffer<mode>* buf;
+
+ public:
+  XDRState(FrontendContext* fc, JS::TranscodeBuffer& buffer, size_t cursor = 0)
+      : mainBuf(fc, buffer, cursor), buf(&mainBuf) {}
+
+  template <typename RangeType>
+  XDRState(FrontendContext* fc, const RangeType& range)
+      : mainBuf(fc, range), buf(&mainBuf) {}
+
+  // No default copy constructor or copying assignment, because |buf|
+  // is an internal pointer.
+  XDRState(const XDRState&) = delete;
+  XDRState& operator=(const XDRState&) = delete;
+
+  ~XDRState() = default;
+
+  FrontendContext* fc() const { return mainBuf.fc(); }
+
+  template <typename T = mozilla::Ok>
+  XDRResultT<T> fail(JS::TranscodeResult code) {
+#ifdef DEBUG
+    MOZ_ASSERT(code != JS::TranscodeResult::Ok);
+    MOZ_ASSERT(validateResultCode(fc(), code));
+    setResultCode(code);
+#endif
+    return mozilla::Err(code);
+  }
+
+  XDRResult align32() {
+    if (!buf->align32()) {
+      return fail(JS::TranscodeResult::Throw);
+    }
+    return mozilla::Ok();
+  }
+
+  bool isAligned32() { return buf->isAligned32(); }
+
+  XDRResult readData(const uint8_t** pptr, size_t length) {
+    const uint8_t* ptr = buf->read(length);
+    if (!ptr) {
+      return fail(JS::TranscodeResult::Failure_BadDecode);
+    }
+    *pptr = ptr;
+    return mozilla::Ok();
+  }
+
+  // Peek the `sizeof(T)` bytes and return the pointer to `*pptr`.
+  // The caller is responsible for aligning the buffer by calling `align32`.
+  template <typename T>
+  XDRResult peekData(const T** pptr) {
+    static_assert(alignof(T) <= 4);
+    MOZ_ASSERT(isAligned32());
+    const uint8_t* ptr = buf->peek(sizeof(T));
+    if (!ptr) {
+      return fail(JS::TranscodeResult::Failure_BadDecode);
+    }
+    *pptr = reinterpret_cast<const T*>(ptr);
+    return mozilla::Ok();
+  }
+
+  // Peek uint32_t data.
+  XDRResult peekUint32(uint32_t* n) {
+    MOZ_ASSERT(mode == XDR_DECODE);
+    const uint8_t* ptr = buf->peek(sizeof(*n));
+    if (!ptr) {
+      return fail(JS::TranscodeResult::Failure_BadDecode);
+    }
+    *n = *reinterpret_cast<const uint32_t*>(ptr);
+    return mozilla::Ok();
+  }
+
+  XDRResult codeUint8(uint8_t* n) {
+    if (mode == XDR_ENCODE) {
+      uint8_t* ptr = buf->write(sizeof(*n));
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Throw);
+      }
+      *ptr = *n;
+    } else {
+      const uint8_t* ptr = buf->read(sizeof(*n));
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Failure_BadDecode);
+      }
+      *n = *ptr;
+    }
+    return mozilla::Ok();
+  }
+
+ private:
+  template <typename T>
+  XDRResult codeUintImpl(T* n) {
+    if (mode == XDR_ENCODE) {
+      uint8_t* ptr = buf->write(sizeof(T));
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Throw);
+      }
+      memcpy(ptr, n, sizeof(T));
+    } else {
+      const uint8_t* ptr = buf->read(sizeof(T));
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Failure_BadDecode);
+      }
+      memcpy(n, ptr, sizeof(T));
+    }
+    return mozilla::Ok();
+  }
+
+ public:
+  XDRResult codeUint16(uint16_t* n) { return codeUintImpl(n); }
+
+  XDRResult codeUint32(uint32_t* n) { return codeUintImpl(n); }
+
+  XDRResult codeUint64(uint64_t* n) { return codeUintImpl(n); }
+
+  void codeUint32At(uint32_t* n, size_t cursor) {
+    if constexpr (mode == XDR_ENCODE) {
+      uint8_t* ptr = buf->bufferAt(cursor);
+      memcpy(ptr, n, sizeof(uint32_t));
+    } else {
+      MOZ_CRASH("not supported.");
+    }
+  }
+
+  const uint8_t* bufferAt(size_t cursor) const {
+    if constexpr (mode == XDR_ENCODE) {
+      return buf->bufferAt(cursor);
+    }
+
+    MOZ_CRASH("not supported.");
+  }
+
+  XDRResult peekArray(size_t n, const uint8_t** p) {
+    if constexpr (mode == XDR_DECODE) {
+      const uint8_t* ptr = buf->peek(n);
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Failure_BadDecode);
+      }
+
+      *p = ptr;
+
+      return mozilla::Ok();
+    }
+
+    MOZ_CRASH("not supported.");
+  }
+
+  /*
+   * Use SFINAE to refuse any specialization which is not an enum.  Uses of
+   * this function do not have to specialize the type of the enumerated field
+   * as C++ will extract the parameterized from the argument list.
+   */
+  template <typename T>
+  XDRResult codeEnum32(T* val, std::enable_if_t<std::is_enum_v<T>>* = nullptr) {
+    // Mix the enumeration value with a random magic number, such that a
+    // corruption with a low-ranged value (like 0) is less likely to cause a
+    // miss-interpretation of the XDR content and instead cause a failure.
+    const uint32_t MAGIC = 0x21AB218C;
+    uint32_t tmp;
+    if (mode == XDR_ENCODE) {
+      tmp = uint32_t(*val) ^ MAGIC;
+    }
+    MOZ_TRY(codeUint32(&tmp));
+    if (mode == XDR_DECODE) {
+      *val = T(tmp ^ MAGIC);
+    }
+    return mozilla::Ok();
+  }
+
+  XDRResult codeDouble(double* dp) {
+    union DoublePun {
+      double d;
+      uint64_t u;
+    } pun;
+    if (mode == XDR_ENCODE) {
+      pun.d = *dp;
+    }
+    MOZ_TRY(codeUint64(&pun.u));
+    if (mode == XDR_DECODE) {
+      *dp = pun.d;
+    }
+    return mozilla::Ok();
+  }
+
+  XDRResult codeMarker(uint32_t magic) {
+    uint32_t actual = magic;
+    MOZ_TRY(codeUint32(&actual));
+    if (actual != magic) {
+      // Fail in debug, but only soft-fail in release
+      MOZ_ASSERT(false, "Bad XDR marker");
+      return fail(JS::TranscodeResult::Failure_BadDecode);
+    }
+    return mozilla::Ok();
+  }
+
+  XDRResult codeBytes(void* bytes, size_t len) {
+    if (len == 0) {
+      return mozilla::Ok();
+    }
+    if (mode == XDR_ENCODE) {
+      uint8_t* ptr = buf->write(len);
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Throw);
+      }
+      memcpy(ptr, bytes, len);
+    } else {
+      const uint8_t* ptr = buf->read(len);
+      if (!ptr) {
+        return fail(JS::TranscodeResult::Failure_BadDecode);
+      }
+      memcpy(bytes, ptr, len);
+    }
+    return mozilla::Ok();
+  }
+
+  // While encoding, code the given data to the buffer.
+  // While decoding, borrow the buffer and return it to `*data`.
+  //
+  // The data can have extra bytes after `sizeof(T)`, and the caller should
+  // provide the entire data length as `length`.
+  //
+  // The caller is responsible for aligning the buffer by calling `align32`.
+  template <typename T>
+  XDRResult borrowedData(T** data, uint32_t length) {
+    static_assert(alignof(T) <= 4);
+    MOZ_ASSERT(isAligned32());
+
+    if (mode == XDR_ENCODE) {
+      MOZ_TRY(codeBytes(*data, length));
+    } else {
+      const uint8_t* cursor = nullptr;
+      MOZ_TRY(readData(&cursor, length));
+      *data = reinterpret_cast<T*>(const_cast<uint8_t*>(cursor));
+    }
+    return mozilla::Ok();
+  }
+
+  // Prefer using a variant below that is encoding aware.
+  XDRResult codeChars(char* chars, size_t nchars);
+
+  XDRResult codeChars(JS::Latin1Char* chars, size_t nchars);
+  XDRResult codeChars(mozilla::Utf8Unit* units, size_t nchars);
+  XDRResult codeChars(char16_t* chars, size_t nchars);
+
+  // Transcode null-terminated strings. When decoding, a new buffer is
+  // allocated and ownership is returned to caller.
+  //
+  // NOTE: Throws if string longer than JSString::MAX_LENGTH.
+  XDRResult codeCharsZ(XDRTranscodeString<char>& buffer);
+  XDRResult codeCharsZ(XDRTranscodeString<char16_t>& buffer);
+};
+
+} /* namespace js */
+
+#endif /* vm_Xdr_h */