[llvm] 0ece51c - Add raw_fd_stream that supports reading/seeking/writing
Jianzhou Zhao via llvm-commits
llvm-commits at lists.llvm.org
Sat Sep 12 00:35:41 PDT 2020
Author: Jianzhou Zhao
Date: 2020-09-12T07:34:19Z
New Revision: 0ece51c60c51f0d4c285dbda3b6cff794041bdd7
URL: https://github.com/llvm/llvm-project/commit/0ece51c60c51f0d4c285dbda3b6cff794041bdd7
DIFF: https://github.com/llvm/llvm-project/commit/0ece51c60c51f0d4c285dbda3b6cff794041bdd7.diff
LOG: Add raw_fd_stream that supports reading/seeking/writing
This is used by https://reviews.llvm.org/D86905 to support bitcode
writer's incremental flush.
Added:
llvm/unittests/Support/raw_fd_stream_test.cpp
Modified:
llvm/include/llvm/Support/raw_ostream.h
llvm/lib/Support/raw_ostream.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/Support/raw_ostream.h b/llvm/include/llvm/Support/raw_ostream.h
index cae57430baff..5e68390bdc8f 100644
--- a/llvm/include/llvm/Support/raw_ostream.h
+++ b/llvm/include/llvm/Support/raw_ostream.h
@@ -47,7 +47,16 @@ class FileLocker;
/// buffered disciplines etc. It is a simple buffer that outputs
/// a chunk at a time.
class raw_ostream {
+public:
+ // Class kinds to support LLVM-style RTTI.
+ enum class OStreamKind {
+ OK_OStream,
+ OK_FDStream,
+ };
+
private:
+ OStreamKind Kind;
+
/// The buffer is handled in such a way that the buffer is
/// uninitialized, unbuffered, or out of space when OutBufCur >=
/// OutBufEnd. Thus a single comparison suffices to determine if we
@@ -105,9 +114,10 @@ class raw_ostream {
static constexpr Colors SAVEDCOLOR = Colors::SAVEDCOLOR;
static constexpr Colors RESET = Colors::RESET;
- explicit raw_ostream(bool unbuffered = false)
- : BufferMode(unbuffered ? BufferKind::Unbuffered
- : BufferKind::InternalBuffer) {
+ explicit raw_ostream(bool unbuffered = false,
+ OStreamKind K = OStreamKind::OK_OStream)
+ : Kind(K), BufferMode(unbuffered ? BufferKind::Unbuffered
+ : BufferKind::InternalBuffer) {
// Start out ready to flush.
OutBufStart = OutBufEnd = OutBufCur = nullptr;
}
@@ -120,6 +130,8 @@ class raw_ostream {
/// tell - Return the current offset with the file.
uint64_t tell() const { return current_pos() + GetNumBytesInBuffer(); }
+ OStreamKind get_kind() const { return Kind; }
+
//===--------------------------------------------------------------------===//
// Configuration Interface
//===--------------------------------------------------------------------===//
@@ -388,8 +400,9 @@ class raw_pwrite_stream : public raw_ostream {
void anchor() override;
public:
- explicit raw_pwrite_stream(bool Unbuffered = false)
- : raw_ostream(Unbuffered) {}
+ explicit raw_pwrite_stream(bool Unbuffered = false,
+ OStreamKind K = OStreamKind::OK_OStream)
+ : raw_ostream(Unbuffered, K) {}
void pwrite(const char *Ptr, size_t Size, uint64_t Offset) {
#ifndef NDEBUG
uint64_t Pos = tell();
@@ -436,10 +449,17 @@ class raw_fd_ostream : public raw_pwrite_stream {
/// Determine an efficient buffer size.
size_t preferred_buffer_size() const override;
+ void anchor() override;
+
+protected:
/// Set the flag indicating that an output error has been encountered.
void error_detected(std::error_code EC) { this->EC = EC; }
- void anchor() override;
+ /// Return the file descriptor.
+ int get_fd() const { return FD; }
+
+ // Update the file position by increasing \p Delta.
+ void inc_pos(uint64_t Delta) { pos += Delta; }
public:
/// Open the specified file for writing. If an error occurs, information
@@ -464,7 +484,8 @@ class raw_fd_ostream : public raw_pwrite_stream {
/// FD is the file descriptor that this writes to. If ShouldClose is true,
/// this closes the file when the stream is destroyed. If FD is for stdout or
/// stderr, it will not be closed.
- raw_fd_ostream(int fd, bool shouldClose, bool unbuffered=false);
+ raw_fd_ostream(int fd, bool shouldClose, bool unbuffered = false,
+ OStreamKind K = OStreamKind::OK_OStream);
~raw_fd_ostream() override;
@@ -548,6 +569,34 @@ raw_fd_ostream &errs();
/// This returns a reference to a raw_ostream which simply discards output.
raw_ostream &nulls();
+//===----------------------------------------------------------------------===//
+// File Streams
+//===----------------------------------------------------------------------===//
+
+/// A raw_ostream of a file for reading/writing/seeking.
+///
+class raw_fd_stream : public raw_fd_ostream {
+public:
+ /// Open the specified file for reading/writing/seeking. If an error occurs,
+ /// information about the error is put into EC, and the stream should be
+ /// immediately destroyed.
+ raw_fd_stream(StringRef Filename, std::error_code &EC);
+
+ /// This reads the \p Size bytes into a buffer pointed by \p Ptr.
+ ///
+ /// \param Ptr The start of the buffer to hold data to be read.
+ ///
+ /// \param Size The number of bytes to be read.
+ ///
+ /// On success, the number of bytes read is returned, and the file position is
+ /// advanced by this number. On error, -1 is returned, use error() to get the
+ /// error code.
+ ssize_t read(char *Ptr, size_t Size);
+
+ /// Check if \p OS is a pointer of type raw_fd_stream*.
+ static bool classof(const raw_ostream *OS);
+};
+
//===----------------------------------------------------------------------===//
// Output Stream Adaptors
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index 83050c8574d9..c803724eb1cf 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -620,8 +620,9 @@ raw_fd_ostream::raw_fd_ostream(StringRef Filename, std::error_code &EC,
/// 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_pwrite_stream(unbuffered), FD(fd), ShouldClose(shouldClose) {
+raw_fd_ostream::raw_fd_ostream(int fd, bool shouldClose, bool unbuffered,
+ OStreamKind K)
+ : raw_pwrite_stream(unbuffered, K), FD(fd), ShouldClose(shouldClose) {
if (FD < 0 ) {
ShouldClose = false;
return;
@@ -904,6 +905,37 @@ raw_ostream &llvm::nulls() {
return S;
}
+//===----------------------------------------------------------------------===//
+// File Streams
+//===----------------------------------------------------------------------===//
+
+raw_fd_stream::raw_fd_stream(StringRef Filename, std::error_code &EC)
+ : raw_fd_ostream(getFD(Filename, EC, sys::fs::CD_CreateAlways,
+ sys::fs::FA_Write | sys::fs::FA_Read,
+ sys::fs::OF_None),
+ true, false, OStreamKind::OK_FDStream) {
+ if (EC)
+ return;
+
+ // Do not support non-seekable files.
+ if (!supportsSeeking())
+ EC = std::make_error_code(std::errc::invalid_argument);
+}
+
+ssize_t raw_fd_stream::read(char *Ptr, size_t Size) {
+ assert(get_fd() >= 0 && "File already closed.");
+ ssize_t Ret = ::read(get_fd(), (void *)Ptr, Size);
+ if (Ret >= 0)
+ inc_pos(Ret);
+ else
+ error_detected(std::error_code(errno, std::generic_category()));
+ return Ret;
+}
+
+bool raw_fd_stream::classof(const raw_ostream *OS) {
+ return OS->get_kind() == OStreamKind::OK_FDStream;
+}
+
//===----------------------------------------------------------------------===//
// raw_string_ostream
//===----------------------------------------------------------------------===//
diff --git a/llvm/unittests/Support/raw_fd_stream_test.cpp b/llvm/unittests/Support/raw_fd_stream_test.cpp
new file mode 100644
index 000000000000..00d834da3210
--- /dev/null
+++ b/llvm/unittests/Support/raw_fd_stream_test.cpp
@@ -0,0 +1,67 @@
+//===- llvm/unittest/Support/raw_fd_stream_test.cpp - raw_fd_stream tests -===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(raw_fd_streamTest, ReadAfterWrite) {
+ SmallString<64> Path;
+ int FD;
+ ASSERT_FALSE(sys::fs::createTemporaryFile("foo", "bar", FD, Path));
+ FileRemover Cleanup(Path);
+ std::error_code EC;
+ raw_fd_stream OS(Path, EC);
+ EXPECT_TRUE(!EC);
+
+ char Bytes[8];
+
+ OS.write("01234567", 8);
+
+ OS.seek(3);
+ EXPECT_EQ(OS.read(Bytes, 2), 2);
+ EXPECT_EQ(Bytes[0], '3');
+ EXPECT_EQ(Bytes[1], '4');
+
+ OS.seek(4);
+ OS.write("xyz", 3);
+
+ OS.seek(0);
+ EXPECT_EQ(OS.read(Bytes, 8), 8);
+ EXPECT_EQ(Bytes[0], '0');
+ EXPECT_EQ(Bytes[1], '1');
+ EXPECT_EQ(Bytes[2], '2');
+ EXPECT_EQ(Bytes[3], '3');
+ EXPECT_EQ(Bytes[4], 'x');
+ EXPECT_EQ(Bytes[5], 'y');
+ EXPECT_EQ(Bytes[6], 'z');
+ EXPECT_EQ(Bytes[7], '7');
+}
+
+TEST(raw_fd_streamTest, DynCast) {
+ {
+ std::error_code EC;
+ raw_fd_stream OS("-", EC);
+ EXPECT_TRUE(dyn_cast<raw_fd_stream>(&OS));
+ }
+ {
+ std::error_code EC;
+ raw_fd_ostream OS("-", EC);
+ EXPECT_FALSE(dyn_cast<raw_fd_stream>(&OS));
+ }
+}
+
+} // namespace
More information about the llvm-commits
mailing list