mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 20:30:14 +01:00
Chandler Carruth
8f8ab23a77
This should clean up our top level directory and the build patterns. No non-mechanical edits here. Just injecting `toolchain/` and `TOOLCHAIN_` and then running formatting tools.
101 lines
3.3 KiB
C++
101 lines
3.3 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 TOOLCHAIN_SOURCE_SOURCEBUFFER_H_
|
|
#define TOOLCHAIN_SOURCE_SOURCEBUFFER_H_
|
|
|
|
#include <string>
|
|
#include <utility>
|
|
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include "llvm/ADT/Twine.h"
|
|
#include "llvm/Support/Error.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:
|
|
static auto CreateFromText(llvm::Twine text,
|
|
llvm::StringRef filename = "/text")
|
|
-> SourceBuffer;
|
|
static auto CreateFromFile(llvm::StringRef filename)
|
|
-> llvm::Expected<SourceBuffer>;
|
|
|
|
// Use one of the factory functions above to create a source buffer.
|
|
SourceBuffer() = delete;
|
|
|
|
// Cannot copy as there may be non-trivial owned file data, see the class
|
|
// comment for details.
|
|
SourceBuffer(const SourceBuffer& arg) = delete;
|
|
|
|
SourceBuffer(SourceBuffer&& arg) noexcept
|
|
: filename_(std::move(arg.filename_)),
|
|
text_(arg.text_),
|
|
is_string_rep_(arg.is_string_rep_) {
|
|
// The easy case in when we don't need to transfer an allocated string
|
|
// representation.
|
|
if (!arg.is_string_rep_) {
|
|
// Take ownership of a non-string representation by clearing its text.
|
|
arg.text_ = llvm::StringRef();
|
|
return;
|
|
}
|
|
|
|
// If the argument is using a string rep we need to move that storage over
|
|
// and recreate our text `StringRef` to point at our storage.
|
|
new (&string_storage_) std::string(std::move(arg.string_storage_));
|
|
text_ = string_storage_;
|
|
}
|
|
|
|
~SourceBuffer();
|
|
|
|
[[nodiscard]] auto Filename() const -> llvm::StringRef { return filename_; }
|
|
|
|
[[nodiscard]] auto Text() const -> llvm::StringRef { return text_; }
|
|
|
|
private:
|
|
std::string filename_;
|
|
|
|
llvm::StringRef text_;
|
|
|
|
bool is_string_rep_;
|
|
|
|
// We use a transparent union to avoid constructing the storage.
|
|
// FIXME: We should replace this and the boolean with an optional which would
|
|
// be much simpler.
|
|
union {
|
|
std::string string_storage_;
|
|
};
|
|
|
|
explicit SourceBuffer(llvm::StringRef fake_filename, std::string buffer_text)
|
|
: filename_(fake_filename.str()),
|
|
is_string_rep_(true),
|
|
string_storage_(std::move(buffer_text)) {
|
|
text_ = string_storage_;
|
|
}
|
|
|
|
explicit SourceBuffer(llvm::StringRef filename)
|
|
: filename_(filename.str()), text_(), is_string_rep_(false) {}
|
|
};
|
|
|
|
} // namespace Carbon
|
|
|
|
#endif // TOOLCHAIN_SOURCE_SOURCEBUFFER_H_
|