[vlc-devel] [PATCH 1/2] libvlc: Add Rust API for writing modules in rust
Alexandre Janniaux
ajanni at videolabs.io
Sun Sep 20 12:33:13 CEST 2020
Hi,
What is the integration plan when we integrate meson?
Do we remove cargo support completly and ony use the
meson rust support?
Regards,
--
Alexandre Janniaux
Videolabs
On Sun, Sep 20, 2020 at 02:39:33AM +0530, Kartik Ohri wrote:
> The API is written in two layers. vlccore-sys
> crate contains one to one bindings of libvlc
> functions. vlccore-rs crate wraps vlccore-sys and
> exposes a Rust idiomatic API for writing modules
> in rust. As of now, the API exposes only a subset
> of the vlc_stream API. More functionality can be
> added to Rust API as required in the future.
> ---
> .gitignore | 2 +-
> configure.ac | 13 ++++
> modules/common.am | 7 ++
> src/Cargo.toml | 2 +
> src/vlccore-rs/Cargo.toml | 10 +++
> src/vlccore-rs/src/lib.rs | 2 +
> src/vlccore-rs/src/stream.rs | 126 ++++++++++++++++++++++++++++++++++
> src/vlccore-rs/src/utils.rs | 19 +++++
> src/vlccore-sys/Cargo.toml | 10 +++
> src/vlccore-sys/src/lib.rs | 3 +
> src/vlccore-sys/src/stream.rs | 46 +++++++++++++
> 11 files changed, 239 insertions(+), 1 deletion(-)
> create mode 100644 src/Cargo.toml
> create mode 100644 src/vlccore-rs/Cargo.toml
> create mode 100644 src/vlccore-rs/src/lib.rs
> create mode 100644 src/vlccore-rs/src/stream.rs
> create mode 100644 src/vlccore-rs/src/utils.rs
> create mode 100644 src/vlccore-sys/Cargo.toml
> create mode 100644 src/vlccore-sys/src/lib.rs
> create mode 100644 src/vlccore-sys/src/stream.rs
>
> diff --git a/.gitignore b/.gitignore
> index fc368212c8..6c049a80b1 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -46,7 +46,7 @@ wxvlc
> vlc_install_dir/*
> plugins.dat
> patches/*
> -
> +**/Cargo.lock
> include/vlc/libvlc_version.h
>
> # Ignore build dirs
> diff --git a/configure.ac b/configure.ac
> index 99e4669942..53d56a725c 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1896,6 +1896,19 @@ AS_IF([test "${enable_sout}" != "no"], [
> ])
> AM_CONDITIONAL([ENABLE_SOUT], [test "${enable_sout}" != "no"])
>
> +dnl Rust Modules
> +AC_ARG_ENABLE([rust],
> + AS_HELP_STRING([--enable-rust], [enable building Rust modules (default disabled)]))
> +AS_IF([test "${enable_rust}" = "yes"],
> + [AC_DEFINE(ENABLE_RUST, 1, [Define to 1 for building rust modules.])])
> +AM_CONDITIONAL([BUILD_RUST], [test "${enable_rust}" = "yes"])
> +if test "${enable_rust}" = "yes"
> +then
> + AC_CHECK_PROG(CARGO, [cargo], [yes], [no])
> + AS_IF([test "x$CARGO" = "xno"],
> + AC_MSG_ERROR([cargo not found. cargo is required to build rust modules]))
> +fi
> +
> dnl Lua modules
> AC_ARG_ENABLE([lua],
> AS_HELP_STRING([--disable-lua],
> diff --git a/modules/common.am b/modules/common.am
> index b991f6ce2f..5edc14ea26 100644
> --- a/modules/common.am
> +++ b/modules/common.am
> @@ -39,6 +39,13 @@ endif
> AM_YFLAGS = -d -Wno-yacc
>
> SUFFIXES = .l .y .asm
> +RUST_API = ../src/vlccore-sys/src/lib.rs \
> + ../src/vlccore-sys/src/stream.rs \
> + ../src/vlccore-sys/Cargo.toml \
> + ../src/vlccore-rs/src/lib.rs \
> + ../src/vlccore-rs/src/stream.rs \
> + ../src/vlccore-rs/Cargo.toml \
> + ../src/Cargo.toml
>
> .asm.lo:
> $(LIBTOOL) --mode=compile --tag=ASM $(X86ASM) $(X86ASMFLAGS) $(X86ASMDEFS) -I$(top_srcdir)/extras/include/x86/ $< -o $@
> diff --git a/src/Cargo.toml b/src/Cargo.toml
> new file mode 100644
> index 0000000000..4b6346fc23
> --- /dev/null
> +++ b/src/Cargo.toml
> @@ -0,0 +1,2 @@
> +[workspace]
> +members = ["vlccore-sys", "vlccore-rs"]
> \ No newline at end of file
> diff --git a/src/vlccore-rs/Cargo.toml b/src/vlccore-rs/Cargo.toml
> new file mode 100644
> index 0000000000..108c849f80
> --- /dev/null
> +++ b/src/vlccore-rs/Cargo.toml
> @@ -0,0 +1,10 @@
> +[package]
> +name = "vlccore-rs"
> +version = "0.1.0"
> +authors = ["Kartik Ohri <kartikohri13 at gmail.com>"]
> +edition = "2018"
> +license = "LGPL-2.1-or-later"
> +
> +[dependencies]
> +libc = "0.2"
> +vlccore-sys = {path="../vlccore-sys"}
> \ No newline at end of file
> diff --git a/src/vlccore-rs/src/lib.rs b/src/vlccore-rs/src/lib.rs
> new file mode 100644
> index 0000000000..9fffcbc8b5
> --- /dev/null
> +++ b/src/vlccore-rs/src/lib.rs
> @@ -0,0 +1,2 @@
> +pub mod stream;
> +pub mod utils;
> diff --git a/src/vlccore-rs/src/stream.rs b/src/vlccore-rs/src/stream.rs
> new file mode 100644
> index 0000000000..afa622b4f1
> --- /dev/null
> +++ b/src/vlccore-rs/src/stream.rs
> @@ -0,0 +1,126 @@
> +use libc::{c_char, c_void};
> +use std::ffi::{CStr, CString};
> +use std::io::{Error, ErrorKind, Read, Result, Seek, SeekFrom};
> +use std::ptr::null_mut;
> +use vlccore_sys::stream as ffi;
> +
> +pub struct Stream {
> + stream: *mut ffi::stream_t,
> +}
> +
> +impl Read for Stream {
> + fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
> + let bytes_read: isize = unsafe {
> + ffi::vlc_stream_Read(self.stream, buf.as_mut_ptr() as *mut c_void, buf.len())
> + };
> + if bytes_read < 0 {
> + Err(Error::new(
> + ErrorKind::Other,
> + "Error while reading from stream",
> + ))
> + } else {
> + Ok(bytes_read as usize)
> + }
> + }
> +}
> +
> +impl Seek for Stream {
> + fn seek(&mut self, pos: SeekFrom) -> Result<u64> {
> + let offset = match pos {
> + SeekFrom::Start(n) => n,
> + SeekFrom::Current(n) => {
> + let len = self.position();
> + if n >= 0 {
> + len.checked_add(n as u64)
> + } else {
> + len.checked_sub(n.wrapping_neg() as u64)
> + }
> + .ok_or(Error::new(ErrorKind::Other, "Position Overflow"))?
> + }
> + SeekFrom::End(n) => self.len().and_then(|position| {
> + if n >= 0 {
> + position.checked_add(n as u64)
> + } else {
> + position.checked_sub(n.wrapping_neg() as u64)
> + }
> + .ok_or(Error::new(ErrorKind::Other, "Position Overflow"))
> + })?,
> + };
> +
> + let result = unsafe { ffi::vlc_stream_Seek(self.stream, offset) };
> + if result != 0 {
> + return Err(Error::new(ErrorKind::Other, "Could not seek stream"));
> + }
> + Ok(offset)
> + }
> +}
> +
> +impl Drop for Stream {
> + fn drop(&mut self) {
> + unsafe { ffi::vlc_stream_Delete(self.stream) }
> + }
> +}
> +
> +impl From<*mut ffi::stream_t> for Stream {
> + fn from(stream: *mut ffi::stream_t) -> Self {
> + Stream { stream }
> + }
> +}
> +
> +impl Stream {
> + pub fn len(&self) -> std::result::Result<u64, Error> {
> + let size: u64 = 0;
> + let result = unsafe {
> + ffi::vlc_stream_Control(
> + self.stream,
> + ffi::stream_query_e_STREAM_GET_SIZE as i32,
> + &size,
> + )
> + };
> + if result != 0 {
> + return Err(Error::new(
> + ErrorKind::Other,
> + "Could not determine stream size",
> + ));
> + }
> + Ok(size)
> + }
> +
> + pub fn position(&self) -> u64 {
> + unsafe { ffi::vlc_stream_Tell(self.stream) }
> + }
> +
> + pub fn eof(&self) -> Result<bool> {
> + Ok(unsafe { ffi::vlc_stream_Eof(self.stream) })
> + }
> +
> + pub fn mimetype(&self) -> Option<String> {
> + let content_type = self.contenttype()?;
> + let index = content_type.chars().position(|c| c == ';')?;
> + Some(content_type[..index].to_owned())
> + }
> +
> + pub fn contenttype(&self) -> Option<String> {
> + let result: *mut c_char = null_mut();
> + unsafe {
> + if ffi::vlc_stream_Control(
> + self.stream,
> + ffi::stream_query_e_STREAM_GET_CONTENT_TYPE as i32,
> + result,
> + ) != 0
> + {
> + return None;
> + } else if result.is_null() {
> + return None;
> + }
> + // FIXME: Free the C pointer received but retain copy of data in Rust
> + CStr::from_ptr(result).to_str().map(|s| s.to_string()).ok()
> + }
> + }
> +
> + pub fn new_with_url(&mut self, url: &str) -> Self {
> + let c_url = CString::new(url).unwrap().as_ptr();
> + let stream = unsafe { ffi::vlc_stream_NewURL(self.stream, c_url) };
> + Stream { stream }
> + }
> +}
> diff --git a/src/vlccore-rs/src/utils.rs b/src/vlccore-rs/src/utils.rs
> new file mode 100644
> index 0000000000..3d9e25ac31
> --- /dev/null
> +++ b/src/vlccore-rs/src/utils.rs
> @@ -0,0 +1,19 @@
> +use libc::{c_char, malloc};
> +use std::ffi::CString;
> +use std::ptr::null_mut;
> +use std::slice::from_raw_parts_mut;
> +
> +pub unsafe fn convert_string_to_ptr(string: String) -> *mut c_char {
> + if string.is_empty() {
> + return std::ptr::null_mut();
> + }
> + let size = string.len() + 1;
> + CString::new(string)
> + .map(|ptr| {
> + let c_ptr = malloc(size * std::mem::size_of::<u8>()) as *mut u8;
> + let slice = from_raw_parts_mut(c_ptr, size);
> + slice[..size].copy_from_slice(ptr.as_bytes_with_nul());
> + c_ptr as *mut c_char
> + })
> + .unwrap_or(null_mut())
> +}
> diff --git a/src/vlccore-sys/Cargo.toml b/src/vlccore-sys/Cargo.toml
> new file mode 100644
> index 0000000000..0dde7b2e7d
> --- /dev/null
> +++ b/src/vlccore-sys/Cargo.toml
> @@ -0,0 +1,10 @@
> +[package]
> +name = "vlccore-sys"
> +version = "0.1.0"
> +authors = ["Kartik Ohri <kartikohri13 at gmail.com>"]
> +edition = "2018"
> +license = "LGPL-2.1-or-later"
> +
> +[dependencies]
> +libc = "0.2"
> +
> diff --git a/src/vlccore-sys/src/lib.rs b/src/vlccore-sys/src/lib.rs
> new file mode 100644
> index 0000000000..08201d88ba
> --- /dev/null
> +++ b/src/vlccore-sys/src/lib.rs
> @@ -0,0 +1,3 @@
> +#![allow(non_camel_case_types)]
> +#![allow(non_upper_case_globals)]
> +pub mod stream;
> diff --git a/src/vlccore-sys/src/stream.rs b/src/vlccore-sys/src/stream.rs
> new file mode 100644
> index 0000000000..e9df363998
> --- /dev/null
> +++ b/src/vlccore-sys/src/stream.rs
> @@ -0,0 +1,46 @@
> +use libc::{c_char, c_int, c_void, size_t, ssize_t};
> +
> +#[repr(C)]
> +pub struct stream_t {
> + _private: [u8; 0],
> +}
> +
> +pub const stream_query_e_STREAM_CAN_SEEK: stream_query_e = 0;
> +pub const stream_query_e_STREAM_CAN_FASTSEEK: stream_query_e = 1;
> +pub const stream_query_e_STREAM_CAN_PAUSE: stream_query_e = 2;
> +pub const stream_query_e_STREAM_CAN_CONTROL_PACE: stream_query_e = 3;
> +pub const stream_query_e_STREAM_GET_SIZE: stream_query_e = 6;
> +pub const stream_query_e_STREAM_GET_PTS_DELAY: stream_query_e = 257;
> +pub const stream_query_e_STREAM_GET_TITLE_INFO: stream_query_e = 258;
> +pub const stream_query_e_STREAM_GET_TITLE: stream_query_e = 259;
> +pub const stream_query_e_STREAM_GET_SEEKPOINT: stream_query_e = 260;
> +pub const stream_query_e_STREAM_GET_META: stream_query_e = 261;
> +pub const stream_query_e_STREAM_GET_CONTENT_TYPE: stream_query_e = 262;
> +pub const stream_query_e_STREAM_GET_SIGNAL: stream_query_e = 263;
> +pub const stream_query_e_STREAM_GET_TAGS: stream_query_e = 264;
> +pub const stream_query_e_STREAM_SET_PAUSE_STATE: stream_query_e = 512;
> +pub const stream_query_e_STREAM_SET_TITLE: stream_query_e = 513;
> +pub const stream_query_e_STREAM_SET_SEEKPOINT: stream_query_e = 514;
> +pub const stream_query_e_STREAM_SET_RECORD_STATE: stream_query_e = 515;
> +pub const stream_query_e_STREAM_SET_PRIVATE_ID_STATE: stream_query_e = 4096;
> +pub const stream_query_e_STREAM_SET_PRIVATE_ID_CA: stream_query_e = 4097;
> +pub const stream_query_e_STREAM_GET_PRIVATE_ID_STATE: stream_query_e = 4098;
> +pub type stream_query_e = ::std::os::raw::c_uint;
> +
> +pub type vlc_object_t = stream_t;
> +
> +extern "C" {
> + pub fn vlc_stream_Read(s: *mut stream_t, buf: *mut c_void, len: size_t) -> ssize_t;
> +
> + pub fn vlc_stream_Tell(s: *const stream_t) -> u64;
> +
> + pub fn vlc_stream_Eof(s: *const stream_t) -> bool;
> +
> + pub fn vlc_stream_Seek(s: *mut stream_t, offset: u64) -> c_int;
> +
> + pub fn vlc_stream_Control(s: *mut stream_t, query: c_int, ...) -> c_int;
> +
> + pub fn vlc_stream_Delete(s: *mut stream_t);
> +
> + pub fn vlc_stream_NewURL(obj: *mut vlc_object_t, url: *const c_char) -> *mut stream_t;
> +}
> --
> 2.25.1
>
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