[llvm] r234895 - Add raw_pwrite_stream type.
Chandler Carruth
chandlerc at google.com
Tue Apr 14 08:12:17 PDT 2015
Just wanted to say, thanks for the iterations here, I like the end result a
lot. =]
On Tue, Apr 14, 2015 at 8:08 AM Rafael Espindola <rafael.espindola at gmail.com>
wrote:
> Author: rafael
> Date: Tue Apr 14 10:00:34 2015
> New Revision: 234895
>
> URL: http://llvm.org/viewvc/llvm-project?rev=234895&view=rev
> Log:
> Add raw_pwrite_stream type.
>
> This is a raw_ostream that also supports pwrite.
> I will be used in a sec.
>
> Added:
> llvm/trunk/unittests/Support/raw_pwrite_stream_test.cpp
> Modified:
> llvm/trunk/include/llvm/Support/raw_ostream.h
> llvm/trunk/lib/Support/raw_ostream.cpp
> llvm/trunk/unittests/Support/CMakeLists.txt
>
> Modified: llvm/trunk/include/llvm/Support/raw_ostream.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/raw_ostream.h?rev=234895&r1=234894&r2=234895&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/Support/raw_ostream.h (original)
> +++ llvm/trunk/include/llvm/Support/raw_ostream.h Tue Apr 14 10:00:34 2015
> @@ -313,13 +313,22 @@ private:
> void copy_to_buffer(const char *Ptr, size_t Size);
> };
>
> +/// An abstract base class for streams implementations that also support a
> +/// pwrite operation. This is usefull for code that can mostly stream out
> data,
> +/// but needs to patch in a header that needs to know the output size.
> +class raw_pwrite_stream : public raw_ostream {
> +public:
> + using raw_ostream::raw_ostream;
> + virtual void pwrite(const char *Ptr, size_t Size, uint64_t Offset) = 0;
> +};
> +
>
> //===----------------------------------------------------------------------===//
> // File Output Streams
>
> //===----------------------------------------------------------------------===//
>
> /// A raw_ostream that writes to a file descriptor.
> ///
> -class raw_fd_ostream : public raw_ostream {
> +class raw_fd_ostream : public raw_pwrite_stream {
> int FD;
> bool ShouldClose;
>
> @@ -378,6 +387,8 @@ public:
> /// to the offset specified from the beginning of the file.
> uint64_t seek(uint64_t off);
>
> + void pwrite(const char *Ptr, size_t Size, uint64_t Offset) override;
> +
> /// Set the stream to attempt to use atomic writes for individual output
> /// routines where possible.
> ///
> @@ -460,7 +471,7 @@ public:
>
> /// A raw_ostream that writes to an SmallVector or SmallString. This is a
> /// simple adaptor class. This class does not encounter output errors.
> -class raw_svector_ostream : public raw_ostream {
> +class raw_svector_ostream : public raw_pwrite_stream {
> SmallVectorImpl<char> &OS;
>
> /// See raw_ostream::write_impl.
> @@ -469,6 +480,12 @@ class raw_svector_ostream : public raw_o
> /// Return the current position within the stream, not counting the
> bytes
> /// currently in the buffer.
> uint64_t current_pos() const override;
> +
> +protected:
> + // Like the regular constructor, but doesn't call init.
> + explicit raw_svector_ostream(SmallVectorImpl<char> &O, unsigned);
> + void init();
> +
> public:
> /// Construct a new raw_svector_ostream.
> ///
> @@ -477,6 +494,8 @@ public:
> explicit raw_svector_ostream(SmallVectorImpl<char> &O);
> ~raw_svector_ostream() override;
>
> + void pwrite(const char *Ptr, size_t Size, uint64_t Offset) override;
> +
> /// This is called when the SmallVector we're appending to is changed
> outside
> /// of the raw_svector_ostream's control. It is only safe to do this
> if the
> /// raw_svector_ostream has previously been flushed.
> @@ -488,7 +507,7 @@ public:
> };
>
> /// A raw_ostream that discards all output.
> -class raw_null_ostream : public raw_ostream {
> +class raw_null_ostream : public raw_pwrite_stream {
> /// See raw_ostream::write_impl.
> void write_impl(const char *Ptr, size_t size) override;
>
> @@ -499,6 +518,18 @@ class raw_null_ostream : public raw_ostr
> public:
> explicit raw_null_ostream() {}
> ~raw_null_ostream() override;
> + void pwrite(const char *Ptr, size_t Size, uint64_t Offset) override;
> +};
> +
> +class buffer_ostream : public raw_svector_ostream {
> + raw_ostream &OS;
> + SmallVector<char, 0> Buffer;
> +
> +public:
> + buffer_ostream(raw_ostream &OS) : raw_svector_ostream(Buffer, 0),
> OS(OS) {
> + init();
> + }
> + ~buffer_ostream() { OS << str(); }
> };
>
> } // end llvm namespace
>
> Modified: llvm/trunk/lib/Support/raw_ostream.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=234895&r1=234894&r2=234895&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Support/raw_ostream.cpp (original)
> +++ llvm/trunk/lib/Support/raw_ostream.cpp Tue Apr 14 10:00:34 2015
> @@ -516,8 +516,8 @@ raw_fd_ostream::raw_fd_ostream(StringRef
> /// FD is the file descriptor that this writes to. If ShouldClose is
> true, this
> /// closes the file when the stream is destroyed.
> raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered)
> - : raw_ostream(unbuffered), FD(fd),
> - ShouldClose(shouldClose), Error(false), UseAtomicWrites(false) {
> + : raw_pwrite_stream(unbuffered), FD(fd), ShouldClose(shouldClose),
> + Error(false), UseAtomicWrites(false) {
> if (FD < 0 ) {
> ShouldClose = false;
> return;
> @@ -630,6 +630,13 @@ uint64_t raw_fd_ostream::seek(uint64_t o
> return pos;
> }
>
> +void raw_fd_ostream::pwrite(const char *Ptr, size_t Size, uint64_t
> Offset) {
> + uint64_t Pos = tell();
> + seek(Offset);
> + write(Ptr, Size);
> + seek(Pos);
> +}
> +
> size_t raw_fd_ostream::preferred_buffer_size() const {
> #if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(__minix)
> // Windows and Minix have no st_blksize.
> @@ -753,7 +760,14 @@ void raw_string_ostream::write_impl(cons
> // capacity. This allows raw_ostream to write directly into the correct
> place,
> // and we only need to set the vector size when the data is flushed.
>
> +raw_svector_ostream::raw_svector_ostream(SmallVectorImpl<char> &O,
> unsigned)
> + : OS(O) {}
> +
> raw_svector_ostream::raw_svector_ostream(SmallVectorImpl<char> &O) :
> OS(O) {
> + init();
> +}
> +
> +void raw_svector_ostream::init() {
> // Set up the initial external buffer. We make sure that the buffer has
> at
> // least 128 bytes free; raw_ostream itself only requires 64, but we
> want to
> // make sure that we don't grow the buffer unnecessarily on destruction
> (when
> @@ -767,6 +781,17 @@ raw_svector_ostream::~raw_svector_ostrea
> flush();
> }
>
> +void raw_svector_ostream::pwrite(const char *Ptr, size_t Size,
> + uint64_t Offset) {
> + flush();
> +
> + uint64_t End = Offset + Size;
> + if (End > OS.size())
> + OS.resize(End);
> +
> + memcpy(OS.begin() + Offset, Ptr, Size);
> +}
> +
> /// resync - This is called when the SmallVector we're appending to is
> changed
> /// outside of the raw_svector_ostream's control. It is only safe to do
> this
> /// if the raw_svector_ostream has previously been flushed.
> @@ -821,3 +846,5 @@ void raw_null_ostream::write_impl(const
> uint64_t raw_null_ostream::current_pos() const {
> return 0;
> }
> +
> +void raw_null_ostream::pwrite(const char *Ptr, size_t Size, uint64_t
> Offset) {}
>
> Modified: llvm/trunk/unittests/Support/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/CMakeLists.txt?rev=234895&r1=234894&r2=234895&view=diff
>
> ==============================================================================
> --- llvm/trunk/unittests/Support/CMakeLists.txt (original)
> +++ llvm/trunk/unittests/Support/CMakeLists.txt Tue Apr 14 10:00:34 2015
> @@ -44,6 +44,7 @@ add_llvm_unittest(SupportTests
> YAMLParserTest.cpp
> formatted_raw_ostream_test.cpp
> raw_ostream_test.cpp
> + raw_pwrite_stream_test.cpp
> )
>
> # ManagedStatic.cpp uses <pthread>.
>
> Added: llvm/trunk/unittests/Support/raw_pwrite_stream_test.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/raw_pwrite_stream_test.cpp?rev=234895&view=auto
>
> ==============================================================================
> --- llvm/trunk/unittests/Support/raw_pwrite_stream_test.cpp (added)
> +++ llvm/trunk/unittests/Support/raw_pwrite_stream_test.cpp Tue Apr 14
> 10:00:34 2015
> @@ -0,0 +1,25 @@
> +//===- raw_pwrite_stream_test.cpp - raw_pwrite_stream tests
> ---------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
>
> +//===----------------------------------------------------------------------===//
> +
> +#include "gtest/gtest.h"
> +#include "llvm/ADT/SmallString.h"
> +#include "llvm/Support/raw_ostream.h"
> +
> +using namespace llvm;
> +
> +namespace {
> +
> +TEST(raw_pwrite_ostreamTest, TestSVector) {
> + SmallString<64> Buffer;
> + raw_svector_ostream OS(Buffer);
> + StringRef Test = "test";
> + OS.pwrite(Test.data(), Test.size(), 0);
> + EXPECT_EQ(Test, OS.str());
> +}
> +}
>
>
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