refactor: project structure, enhance basic traits

[AsakuraMizu]

This is the first stage of refactoring, extracted from #4.

Changes

• Improve the project structure and organize traits by module
• Upgrade to 2024 edition
• Add more information to README.md, update crate description and documentation
• Add following methods to traits:
  • Read::read_buf/Read::read_buf_exact/Read::by_ref
  • BufRead::skip_until/BufRead::split/BufRead::lines
  • Seek::stream_len/Seek::seek_relative
• Add more trait implementations
• Use memchr to optimize BufRead::read_until (also used in BufRead::skip_until)
• Update axerrno to 0.2

[Copilot]

Pull request overview

This PR implements the first stage of refactoring for the axio crate, reorganizing the project structure and expanding functionality to better align with std::io.

Key Changes:

• Reorganized code by splitting traits into separate modules (read, write, seek) with dedicated implementation files
• Added new trait methods including Read::read_buf, Read::read_buf_exact, BufRead::skip_until, BufRead::split, BufRead::lines, Seek::stream_len, and Seek::seek_relative
• Integrated memchr crate for optimized byte searching in BufRead::read_until and BufRead::skip_until

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Cargo.toml	Updated edition to 2024, bumped axerrno dependency to 0.2, added memchr dependency
README.md	Enhanced documentation with feature descriptions, differences from std::io, limitations, and license information
src/lib.rs	Refactored to use module-based organization, added DEFAULT_BUF_SIZE constant, re-exported types from axerrno
src/prelude.rs	Updated documentation example and import path to use crate:: instead of super::
src/write/mod.rs	New module defining Write trait with write, flush, write_all, write_fmt, and by_ref methods
src/write/impls.rs	Implementations of Write trait for references, Box, byte slices, Vec, VecDeque, and BorrowedCursor
src/seek/mod.rs	New module defining Seek trait and SeekFrom enum with additional methods stream_len and seek_relative
src/seek/impls.rs	Forwarding implementations of Seek trait for references and Box
src/read/mod.rs	New module defining Read and BufRead traits with expanded functionality, including Split and Lines iterators
src/read/impls.rs	Comprehensive implementations of Read and BufRead for various types including slices, Box, VecDeque
src/error.rs	Deleted - functionality moved to lib.rs via re-exports from axerrno
src/impls.rs	Deleted - implementations reorganized into module-specific impls.rs files

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[Copilot]

Pull request overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated 2 comments.

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[AsakuraMizu]

The value of DEFAULT_BUF_SIZE needs to be discussed.

In std it is configured as follows:

// Bare metal platforms usually have very small amounts of RAM
// (in the order of hundreds of KB)
pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };

512 seems a bit small for us, while 8 * 1024 is a bit large. I've currently chosen 2 * 1024, which is right in between.

[Azure-stars]

The value of DEFAULT_BUF_SIZE needs to be discussed.

In std it is configured as follows:

// Bare metal platforms usually have very small amounts of RAM
// (in the order of hundreds of KB)
pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };

512 seems a bit small for us, while 8 * 1024 is a bit large. I've currently chosen 2 * 1024, which is right in between.

Can we support different size via feature like https://github.com/arceos-org/arceos/blob/main/modules/axalloc/Cargo.toml#L17-L18?

Because we may be used at different platforms.

[AsakuraMizu]

Can we support different size via feature like arceos-org/arceos@main/modules/axalloc/Cargo.toml#L17-L18?

Because we may be used at different platforms.

That sounds reasonable. But now we need to select a suitable set of default buffer sizes.

[AsakuraMizu]

Oh, now there's a problem. Should we silently ignore Error::Interrupted like std? I hadn't thought much about it before, but now it seems like we shouldn't; all errors should be reported. @Azure-stars