Files
carbon-lang/toolchain/source/source_buffer.h
T
Richard SmithandChandler Carruth 9154c6410e Support for reading source code from stdin and other unusual places. (#3416)
- Treat an input of `-` as meaning stdin.

- Fix building of an llvm::MemoryBuffer from a non-regular file.

- Do not enforce filename restrictions on non-regular files.

- Do not invent an output file name based on the name of a non-regular
file.

---------

Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
2023-11-22 03:48:10 +00:00

88 lines
3.2 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef CARBON_TOOLCHAIN_SOURCE_SOURCE_BUFFER_H_
#define CARBON_TOOLCHAIN_SOURCE_SOURCE_BUFFER_H_
#include <memory>
#include <string>
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "toolchain/diagnostics/diagnostic_emitter.h"
namespace Carbon {
// A buffer of Carbon source code.
//
// This class holds a buffer of Carbon source code as text and makes it
// available for use in the rest of the Carbon compiler. It owns the memory for
// the underlying source code text and ensures it lives as long as the buffer
// objects.
//
// Every buffer of source code text is notionally loaded from a Carbon source
// file, even if provided directly when constructing the buffer. The name that
// should be used for that Carbon source file is also retained and made
// available.
//
// Because the underlying memory for the source code text may have been read
// from a file, and we may want to use facilities like `mmap` to simply map that
// file into memory, the buffer itself is not copyable to avoid needing to
// define copy semantics for a mapped file. We can relax this restriction with
// some implementation complexity in the future if needed.
class SourceBuffer {
public:
// Opens and reads the contents of stdin. Returns a SourceBuffer on success.
// Prints an error and returns nullopt on failure.
static auto CreateFromStdin(DiagnosticConsumer& consumer)
-> std::optional<SourceBuffer>;
// Opens the requested file. Returns a SourceBuffer on success. Prints an
// error and returns nullopt on failure.
static auto CreateFromFile(llvm::vfs::FileSystem& fs,
llvm::StringRef filename,
DiagnosticConsumer& consumer)
-> std::optional<SourceBuffer>;
// Use one of the factory functions above to create a source buffer.
SourceBuffer() = delete;
[[nodiscard]] auto filename() const -> llvm::StringRef { return filename_; }
[[nodiscard]] auto text() const -> llvm::StringRef {
return text_->getBuffer();
}
[[nodiscard]] auto is_regular_file() const -> bool {
return is_regular_file_;
}
private:
// Creates a `SourceBuffer` from the given `llvm::MemoryBuffer`. Prints an
// error and returns nullopt on failure.
static auto CreateFromMemoryBuffer(
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> buffer,
llvm::StringRef filename, bool is_regular_file,
DiagnosticConsumer& consumer) -> std::optional<SourceBuffer>;
explicit SourceBuffer(std::string filename,
std::unique_ptr<llvm::MemoryBuffer> text,
bool is_regular_file)
: filename_(std::move(filename)),
text_(std::move(text)),
is_regular_file_(is_regular_file) {}
std::string filename_;
std::unique_ptr<llvm::MemoryBuffer> text_;
// Whether this buffer is a regular file, rather than stdin or a named pipe or
// similar.
bool is_regular_file_;
};
} // namespace Carbon
#endif // CARBON_TOOLCHAIN_SOURCE_SOURCE_BUFFER_H_