Initial commit

vendor/github.com/cockroachdb/pebble/internal/manual/manual.go

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+// Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
+package manual
+
+// #include <stdlib.h>
+import "C"
+import "unsafe"
+
+// The go:linkname directives provides backdoor access to private functions in
+// the runtime. Below we're accessing the throw function.
+
+//go:linkname throw runtime.throw
+func throw(s string)
+
+// TODO(peter): Rather than relying an C malloc/free, we could fork the Go
+// runtime page allocator and allocate large chunks of memory using mmap or
+// similar.
+
+// New allocates a slice of size n. The returned slice is from manually managed
+// memory and MUST be released by calling Free. Failure to do so will result in
+// a memory leak.
+func New(n int) []byte {
+	if n == 0 {
+		return make([]byte, 0)
+	}
+	// We need to be conscious of the Cgo pointer passing rules:
+	//
+	//   https://golang.org/cmd/cgo/#hdr-Passing_pointers
+	//
+	//   ...
+	//   Note: the current implementation has a bug. While Go code is permitted
+	//   to write nil or a C pointer (but not a Go pointer) to C memory, the
+	//   current implementation may sometimes cause a runtime error if the
+	//   contents of the C memory appear to be a Go pointer. Therefore, avoid
+	//   passing uninitialized C memory to Go code if the Go code is going to
+	//   store pointer values in it. Zero out the memory in C before passing it
+	//   to Go.
+	ptr := C.calloc(C.size_t(n), 1)
+	if ptr == nil {
+		// NB: throw is like panic, except it guarantees the process will be
+		// terminated. The call below is exactly what the Go runtime invokes when
+		// it cannot allocate memory.
+		throw("out of memory")
+	}
+	// Interpret the C pointer as a pointer to a Go array, then slice.
+	return (*[MaxArrayLen]byte)(unsafe.Pointer(ptr))[:n:n]
+}
+
+// Free frees the specified slice.
+func Free(b []byte) {
+	if cap(b) != 0 {
+		if len(b) == 0 {
+			b = b[:cap(b)]
+		}
+		ptr := unsafe.Pointer(&b[0])
+		C.free(ptr)
+	}
+}

vendor/github.com/cockroachdb/pebble/internal/manual/manual_32bit.go

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+// Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
+//go:build 386 || amd64p32 || arm || armbe || mips || mipsle || mips64p32 || mips64p32le || ppc || sparc
+// +build 386 amd64p32 arm armbe mips mipsle mips64p32 mips64p32le ppc sparc
+
+package manual
+
+const (
+	// MaxArrayLen is a safe maximum length for slices on this architecture.
+	MaxArrayLen = 1<<31 - 1
+)

vendor/github.com/cockroachdb/pebble/internal/manual/manual_64bit.go

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+// Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
+//go:build amd64 || arm64 || arm64be || ppc64 || ppc64le || mips64 || mips64le || s390x || sparc64
+// +build amd64 arm64 arm64be ppc64 ppc64le mips64 mips64le s390x sparc64
+
+package manual
+
+const (
+	// MaxArrayLen is a safe maximum length for slices on this architecture.
+	MaxArrayLen = 1<<50 - 1
+)

vendor/github.com/cockroachdb/pebble/internal/manual/manual_nocgo.go

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+// Copyright 2020 The LevelDB-Go and Pebble Authors. All rights reserved. Use
+// of this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+
+//go:build !cgo
+// +build !cgo
+
+package manual
+
+// Provides versions of New and Free when cgo is not available (e.g. cross
+// compilation).
+
+// New allocates a slice of size n.
+func New(n int) []byte {
+	return make([]byte, n)
+}
+
+// Free frees the specified slice.
+func Free(b []byte) {
+}