gstreamer-rs/gstreamer/src/typefind.rs

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// Copyright (C) 2017 Sebastian Dröge <sebastian@centricular.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
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use ffi;
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use Caps;
use Plugin;
use TypeFindFactory;
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use TypeFindProbability;
use glib;
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use glib::translate::*;
use glib_ffi;
use std::marker::PhantomData;
use std::mem;
use std::ptr;
use std::slice;
#[repr(C)]
pub struct TypeFind<'a>(ffi::GstTypeFind, PhantomData<&'a ()>);
pub trait TypeFindImpl {
fn peek(&mut self, offset: i64, size: u32) -> Option<&[u8]>;
fn suggest(&mut self, probability: TypeFindProbability, caps: &Caps);
fn get_length(&self) -> Option<u64> {
None
}
}
impl<'a> TypeFind<'a> {
pub fn register<
'b,
'c,
'd,
P: Into<Option<&'b Plugin>>,
R: Into<Option<&'c str>>,
S: Into<Option<&'d Caps>>,
F,
>(
plugin: P,
name: &str,
rank: u32,
extensions: R,
possible_caps: S,
func: F,
) -> Result<(), glib::error::BoolError>
where
F: Fn(&mut TypeFind) + Send + Sync + 'static,
{
let plugin = plugin.into();
let extensions = extensions.into();
let possible_caps = possible_caps.into();
unsafe {
let func: Box<Box<Fn(&mut TypeFind) + Send + Sync + 'static>> =
Box::new(Box::new(func));
let func = Box::into_raw(func);
let res = ffi::gst_type_find_register(
plugin.to_glib_none().0,
name.to_glib_none().0,
rank,
Some(type_find_trampoline),
extensions.to_glib_none().0,
possible_caps.to_glib_none().0,
func as *mut _,
Some(type_find_closure_drop),
);
glib::error::BoolError::from_glib(res, "Failed to register typefind factory")
}
}
pub fn peek(&mut self, offset: i64, size: u32) -> Option<&[u8]> {
unsafe {
let data = ffi::gst_type_find_peek(&mut self.0, offset, size);
if data.is_null() {
None
} else {
Some(slice::from_raw_parts(data, size as usize))
}
}
}
pub fn suggest(&mut self, probability: TypeFindProbability, caps: &Caps) {
unsafe {
ffi::gst_type_find_suggest(
&mut self.0,
probability.to_glib() as u32,
caps.to_glib_none().0,
);
}
}
}
unsafe impl<'a> Send for TypeFind<'a> {}
impl TypeFindFactory {
pub fn call_function(&self, find: &mut TypeFindImpl) {
unsafe {
let find_ptr = &find as *const &mut TypeFindImpl as glib_ffi::gpointer;
let mut find = ffi::GstTypeFind {
peek: Some(type_find_peek),
suggest: Some(type_find_suggest),
data: find_ptr,
get_length: Some(type_find_get_length),
_gst_reserved: [ptr::null_mut(); 4],
};
ffi::gst_type_find_factory_call_function(self.to_glib_none().0, &mut find)
}
}
}
unsafe extern "C" fn type_find_trampoline(
find: *mut ffi::GstTypeFind,
user_data: glib_ffi::gpointer,
) {
#[cfg_attr(feature = "cargo-clippy", allow(transmute_ptr_to_ref))]
let func: &&(Fn(&mut TypeFind) + Send + Sync + 'static) = mem::transmute(user_data);
func(&mut *(find as *mut TypeFind));
}
unsafe extern "C" fn type_find_closure_drop(data: glib_ffi::gpointer) {
Box::<Box<Fn(&mut TypeFind) + Send + Sync + 'static>>::from_raw(data as *mut _);
}
unsafe extern "C" fn type_find_peek(data: glib_ffi::gpointer, offset: i64, size: u32) -> *const u8 {
let find: &mut &mut TypeFindImpl = &mut *(data as *mut &mut TypeFindImpl);
match find.peek(offset, size) {
None => ptr::null(),
Some(data) => data.as_ptr(),
}
}
unsafe extern "C" fn type_find_suggest(
data: glib_ffi::gpointer,
probability: u32,
caps: *mut ffi::GstCaps,
) {
let find: &mut &mut TypeFindImpl = &mut *(data as *mut &mut TypeFindImpl);
find.suggest(from_glib(probability as i32), &from_glib_borrow(caps));
}
unsafe extern "C" fn type_find_get_length(data: glib_ffi::gpointer) -> u64 {
use std::u64;
let find: &mut &mut TypeFindImpl = &mut *(data as *mut &mut TypeFindImpl);
find.get_length().unwrap_or(u64::MAX)
}
pub struct SliceTypeFind<T: AsRef<[u8]>> {
pub probability: Option<TypeFindProbability>,
pub caps: Option<Caps>,
data: T,
}
impl<T: AsRef<[u8]>> SliceTypeFind<T> {
pub fn new(data: T) -> SliceTypeFind<T> {
SliceTypeFind {
probability: None,
caps: None,
data,
}
}
pub fn run(&mut self) {
let factories = TypeFindFactory::get_list();
for factory in factories {
factory.call_function(self);
if let Some(prob) = self.probability {
if prob >= TypeFindProbability::Maximum {
break;
}
}
}
}
pub fn type_find(data: T) -> (TypeFindProbability, Option<Caps>) {
let mut t = SliceTypeFind {
probability: None,
caps: None,
data,
};
t.run();
(t.probability.unwrap_or(TypeFindProbability::None), t.caps)
}
}
impl<T: AsRef<[u8]>> TypeFindImpl for SliceTypeFind<T> {
fn peek(&mut self, offset: i64, size: u32) -> Option<&[u8]> {
let data = self.data.as_ref();
let len = data.len();
let offset = if offset >= 0 {
offset as usize
} else {
if len < offset.abs() as usize {
return None;
}
len - (offset.abs() as usize)
};
let size = size as usize;
if offset + size <= len {
Some(&data[offset..(offset + size)])
} else {
None
}
}
fn suggest(&mut self, probability: TypeFindProbability, caps: &Caps) {
match self.probability {
None => {
self.probability = Some(probability);
self.caps = Some(caps.clone());
}
Some(old_probability) if old_probability < probability => {
self.probability = Some(probability);
self.caps = Some(caps.clone());
}
_ => (),
}
}
fn get_length(&self) -> Option<u64> {
Some(self.data.as_ref().len() as u64)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_typefind_call_function() {
::init().unwrap();
let xml_factory = TypeFindFactory::get_list()
.iter()
.cloned()
.find(|f| {
f.get_caps()
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.map(|c| {
c.get_structure(0)
.map(|s| s.get_name() == "application/xml")
.unwrap_or(false)
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})
.unwrap_or(false)
})
.unwrap();
let data = b"<?xml version=\"1.0\"?><test>test</test>";
let data = &data[..];
let mut typefind = SliceTypeFind::new(&data);
xml_factory.call_function(&mut typefind);
assert_eq!(
typefind.caps,
Some(Caps::new_simple("application/xml", &[]))
);
assert_eq!(typefind.probability, Some(TypeFindProbability::Minimum));
}
#[test]
fn test_typefind_register() {
::init().unwrap();
TypeFind::register(
None,
"test_typefind",
::Rank::Primary.to_glib() as u32,
None,
&Caps::new_simple("test/test", &[]),
|typefind| {
let mut found = false;
if let Some(data) = typefind.peek(0, 8) {
if data == b"abcdefgh" {
found = true;
}
}
if found {
typefind.suggest(
TypeFindProbability::Likely,
&Caps::new_simple("test/test", &[]),
);
}
},
)
.unwrap();
let data = b"abcdefgh";
let data = &data[..];
let (probability, caps) = SliceTypeFind::type_find(&data);
assert_eq!(caps, Some(Caps::new_simple("test/test", &[])));
assert_eq!(probability, TypeFindProbability::Likely);
}
}