write.hpp

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#pragma once
 
/// @file userver/fs/write.hpp
/// @brief filesystem write functions
 
#include <string>
 
#include <userver/engine/task/task_processor_fwd.hpp>
#include <userver/utils/boost_filesystem_file_status.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace fs {
 
/// @{
/// @brief Create directory and all necessary parent elements. Condition when
/// path already exists and is a directory treated as "success" and no exception
/// is thrown.
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path directory to create
/// @throws std::runtime_error if there was an error while
/// creating directories
void CreateDirectories(engine::TaskProcessor& async_tp, std::string_view path, boost::filesystem::perms perms);
 
void CreateDirectories(engine::TaskProcessor& async_tp, std::string_view path);
/// @}
 
/// @brief Rewrite file contents asynchronously
/// It doesn't provide strict atomic guarantees. If you need them, use
/// `fs::RewriteFileContentsAtomically`.
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file to rewrite
/// @param contents new file contents
/// @throws std::runtime_error if failed to overwrite
void RewriteFileContents(engine::TaskProcessor& async_tp, const std::string& path, std::string_view contents);
 
/// @brief Renames existing file
/// @param async_tp TaskProcessor for synchronous waiting
/// @param source path to move from
/// @param destination path to move to
/// @throws std::runtime_error
void Rename(engine::TaskProcessor& async_tp, const std::string& source, const std::string& destination);
 
/// @brief Rewrite file contents atomically
/// Write contents to temporary file in the same directory,
/// then atomically replaces the destination file with the temporary file.
/// Effectively does write()+sync()+rename()+sync(directory).
/// It does both sync(2) for file and on the directory, so after successful
/// return the file must persist on the filesystem.
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file path to rewrite
/// @param contents new file contents
/// @param perms new file permissions
/// @throws std::runtime_error
void RewriteFileContentsAtomically(
    engine::TaskProcessor& async_tp,
    const std::string& path,
    std::string_view contents,
    boost::filesystem::perms perms
);
 
/// @brief Change file mode
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file path to chmod
/// @param perms new file permissions
/// @throws std::runtime_error
void Chmod(engine::TaskProcessor& async_tp, const std::string& path, boost::filesystem::perms perms);
 
/// @brief Remove existing file
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file path to chmod
/// @returns true if successfully removed, false if file doesn't exist
/// @throws std::runtime_error
bool RemoveSingleFile(engine::TaskProcessor& async_tp, const std::string& path);
 
}  // namespace fs
 
USERVER_NAMESPACE_END