read.hpp

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#pragma once
 
/// @file userver/fs/read.hpp
/// @brief functions for asynchronous file read operations
 
#include <memory>
#include <string>
#include <unordered_map>
 
#include <userver/engine/task/task_processor_fwd.hpp>
#include <userver/utils/flags.hpp>
 
USERVER_NAMESPACE_BEGIN
 
/// @brief filesystem support
namespace fs {
 
/// @brief Struct file with load data
struct FileInfoWithData {
    std::string data;
    std::string extension;
};
 
using FileInfoWithDataConstPtr = std::shared_ptr<const FileInfoWithData>;
using FileInfoWithDataMap = std::unordered_map<std::string, FileInfoWithDataConstPtr>;
 
enum class SettingsReadFile {
    kNone = 0,
    /// Skip hidden files,
    kSkipHidden = 1 << 0,
};
 
/// @brief Returns relative path from full path
/// @param path full path, must start with `dir`
/// @param dir directory path to get relative path
/// @note it does not access filesystem, the relative path is calculated
/// lexically.
std::string GetLexicallyRelative(std::string_view path, std::string_view dir);
 
/// @brief Returns files from recursively traversed directory
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path to directory to traverse recursively
/// @param flags settings read files
/// @returns map with relative to `path` filepaths and file info
/// @throws std::runtime_error if read fails for any reason (e.g. no such file,
/// read error, etc.),
FileInfoWithDataMap ReadRecursiveFilesInfoWithData(
    engine::TaskProcessor& async_tp,
    const std::string& path,
    utils::Flags<SettingsReadFile> flags = {SettingsReadFile::kSkipHidden}
);
 
/// @brief Reads file contents asynchronously
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file to open
/// @returns file contents
/// @throws std::runtime_error if read fails for any reason (e.g. no such file,
/// read error, etc.),
std::string ReadFileContents(engine::TaskProcessor& async_tp, const std::string& path);
 
/// @brief Checks whether the file exists asynchronously
/// @param async_tp TaskProcessor for synchronous waiting
/// @param path file path to check
/// @returns true if file exists, false if file doesn't exist
/// @throws std::runtime_error if something goes wrong (e.g. out of file
/// descriptors)
bool FileExists(engine::TaskProcessor& async_tp, const std::string& path);
 
}  // namespace fs
 
USERVER_NAMESPACE_END