gstreamer-rs/gstreamer/src/iterator.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;
use glib::translate::*;
use glib_ffi;
use glib_ffi::{gconstpointer, gpointer};
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use gobject_ffi;
use std::mem;
use std::ptr;
use glib;
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use glib::Value;
use glib::StaticType;
use glib::value::{FromValueOptional, ToValue};
use std::sync::Arc;
use std::ffi::CString;
use std::marker::PhantomData;
use std::iter::Iterator as StdIterator;
use std::fmt;
use std::error::Error;
#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
pub enum IteratorError {
Resync,
Error,
}
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impl fmt::Display for IteratorError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
IteratorError::Resync => write!(f, "Resync"),
IteratorError::Error => write!(f, "Error"),
}
}
}
impl Error for IteratorError {
fn description(&self) -> &str {
match *self {
IteratorError::Resync => "Resync",
IteratorError::Error => "Error",
}
}
}
// Implemented manually so that we can use generics for the item
pub struct Iterator<T> {
iter: *mut ffi::GstIterator,
borrowed: bool,
phantom: PhantomData<T>,
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}
impl<T> Iterator<T>
where
for<'a> T: FromValueOptional<'a> + 'static,
{
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pub fn resync(&mut self) {
unsafe {
ffi::gst_iterator_resync(self.to_glib_none_mut().0);
}
}
pub fn filter<F>(self, func: F) -> Self
where
F: Fn(T) -> bool + Send + Sync + 'static,
{
unsafe {
let it = self.to_glib_none().0;
mem::forget(self);
let func_box: Box<Fn(T) -> bool + Send + Sync + 'static> = Box::new(func);
// FIXME: Use Value::from_type once we depend on new enough GLib
let mut closure_value = glib::Value::uninitialized();
gobject_ffi::g_value_init(
closure_value.to_glib_none_mut().0,
filter_boxed_get_type::<T>(),
);
gobject_ffi::g_value_set_boxed(
closure_value.to_glib_none_mut().0,
Arc::into_raw(Arc::new(func_box)) as gpointer,
);
let it = from_glib_full(ffi::gst_iterator_filter(
it as *mut _,
Some(filter_trampoline::<T>),
closure_value.to_glib_none().0,
));
it
}
}
pub fn find_simple<F>(&mut self, func: F) -> Option<T>
where
F: FnMut(T) -> bool,
{
unsafe {
let mut elem = glib::Value::uninitialized();
let mut func = func;
let func_obj: &mut (FnMut(T) -> bool) = &mut func;
let func_ptr = &func_obj as *const &mut (FnMut(T) -> bool) as gpointer;
let res = from_glib(ffi::gst_iterator_find_custom(
self.to_glib_none_mut().0,
Some(find_trampoline::<T>),
elem.to_glib_none_mut().0,
func_ptr,
));
if res {
Some(elem.get::<T>().unwrap())
} else {
None
}
}
}
pub fn foreach<F>(&mut self, func: F) -> Result<(), IteratorError>
where
F: FnMut(T),
{
unsafe {
let mut func = func;
let func_obj: &mut (FnMut(T)) = &mut func;
let func_ptr = &func_obj as *const &mut (FnMut(T)) as gpointer;
let res = ffi::gst_iterator_foreach(
self.to_glib_none_mut().0,
Some(foreach_trampoline::<T>),
func_ptr,
);
match res {
ffi::GST_ITERATOR_OK | ffi::GST_ITERATOR_DONE => Ok(()),
ffi::GST_ITERATOR_RESYNC => Err(IteratorError::Resync),
ffi::GST_ITERATOR_ERROR | _ => Err(IteratorError::Error),
}
}
}
pub fn fold_with_early_exit<F, U>(&mut self, init: U, func: F) -> Result<U, IteratorError>
where
F: FnMut(U, T) -> Result<U, U>,
{
unsafe {
let mut func = func;
let func_obj: &mut (FnMut(U, T) -> Result<U, U>) = &mut func;
let func_ptr = &func_obj as *const &mut (FnMut(U, T) -> Result<U, U>) as gpointer;
let mut accum = Some(init);
// FIXME: Use Value::from_type once we depend on new enough GLib
let mut ret = glib::Value::uninitialized();
gobject_ffi::g_value_init(ret.to_glib_none_mut().0, gobject_ffi::G_TYPE_POINTER);
gobject_ffi::g_value_set_pointer(
ret.to_glib_none_mut().0,
&mut accum as *mut _ as gpointer,
);
let res = ffi::gst_iterator_fold(
self.to_glib_none_mut().0,
Some(fold_trampoline::<T, U>),
ret.to_glib_none_mut().0,
func_ptr,
);
match res {
ffi::GST_ITERATOR_OK | ffi::GST_ITERATOR_DONE => Ok(accum.unwrap()),
ffi::GST_ITERATOR_RESYNC => Err(IteratorError::Resync),
ffi::GST_ITERATOR_ERROR | _ => Err(IteratorError::Error),
}
}
}
}
impl<T> Iterator<T>
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
pub fn new<I: IteratorImpl<T>>(imp: I) -> Self {
static DUMMY_COOKIE: u32 = 0;
unsafe {
let it = ffi::gst_iterator_new(
mem::size_of::<RsIterator<T, I>>() as u32,
T::static_type().to_glib(),
ptr::null_mut(),
&DUMMY_COOKIE as *const _ as *mut _,
Some(rs_iterator_copy::<T, I>),
Some(rs_iterator_next::<T, I>),
None,
Some(rs_iterator_resync::<T, I>),
Some(rs_iterator_free::<T, I>),
);
{
let it = it as *mut RsIterator<T, I>;
(*it).imp = Some(imp);
}
from_glib_full(it)
}
}
}
impl<T> Iterator<T>
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Clone + Send + 'static,
{
pub fn from_vec(items: Vec<T>) -> Self {
Self::new(VecIteratorImpl::new(items))
}
}
impl<T> StdIterator for Iterator<T>
where
for<'a> T: FromValueOptional<'a> + 'static,
{
type Item = Result<T, IteratorError>;
fn next(&mut self) -> Option<Result<T, IteratorError>> {
unsafe {
let mut value = Value::uninitialized();
let res = ffi::gst_iterator_next(self.to_glib_none_mut().0, value.to_glib_none_mut().0);
match res {
ffi::GST_ITERATOR_OK => match value.get::<T>() {
Some(value) => Some(Ok(value)),
None => Some(Err(IteratorError::Error)),
},
ffi::GST_ITERATOR_DONE => None,
ffi::GST_ITERATOR_RESYNC => Some(Err(IteratorError::Resync)),
ffi::GST_ITERATOR_ERROR | _ => Some(Err(IteratorError::Error)),
}
}
}
}
#[repr(C)]
struct RsIterator<T, I: IteratorImpl<T>>
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
iter: ffi::GstIterator,
imp: Option<I>,
phantom: PhantomData<T>,
}
pub trait IteratorImpl<T>: Clone + Send + 'static
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
fn next(&mut self) -> Option<Result<T, IteratorError>>;
fn resync(&mut self);
}
unsafe extern "C" fn rs_iterator_copy<T, I: IteratorImpl<T>>(
it: *const ffi::GstIterator,
copy: *mut ffi::GstIterator,
) where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
callback_guard!();
let it = it as *const RsIterator<T, I>;
let copy = copy as *mut RsIterator<T, I>;
ptr::write(&mut (*copy).imp, (*it).imp.clone());
}
unsafe extern "C" fn rs_iterator_free<T, I: IteratorImpl<T>>(it: *mut ffi::GstIterator)
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
callback_guard!();
let it = it as *mut RsIterator<T, I>;
let _ = (*it).imp.take();
}
unsafe extern "C" fn rs_iterator_next<T, I: IteratorImpl<T>>(
it: *mut ffi::GstIterator,
result: *mut gobject_ffi::GValue,
) -> ffi::GstIteratorResult
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
callback_guard!();
let it = it as *mut RsIterator<T, I>;
match (*it).imp.as_mut().map(|imp| imp.next()).unwrap() {
Some(Ok(value)) => {
let value = value.to_value();
ptr::write(result, ptr::read(value.to_glib_none().0));
mem::forget(value);
ffi::GST_ITERATOR_OK
}
None => ffi::GST_ITERATOR_DONE,
Some(Err(res)) => match res {
IteratorError::Resync => ffi::GST_ITERATOR_RESYNC,
IteratorError::Error => ffi::GST_ITERATOR_ERROR,
},
}
}
unsafe extern "C" fn rs_iterator_resync<T, I: IteratorImpl<T>>(it: *mut ffi::GstIterator)
where
for<'a> T: FromValueOptional<'a> + StaticType + ToValue + Send + 'static,
{
callback_guard!();
let it = it as *mut RsIterator<T, I>;
(*it).imp.as_mut().map(|imp| imp.resync()).unwrap();
}
#[derive(Clone)]
struct VecIteratorImpl<T> {
pos: usize,
items: Vec<T>,
}
impl<T> VecIteratorImpl<T>
where
for<'a> T: StaticType + ToValue + FromValueOptional<'a> + Clone + Send + 'static,
{
fn new(items: Vec<T>) -> Self {
Self {
pos: 0,
items: items,
}
}
}
impl<T> IteratorImpl<T> for VecIteratorImpl<T>
where
for<'a> T: StaticType + ToValue + FromValueOptional<'a> + Clone + Send + 'static,
{
fn next(&mut self) -> Option<Result<T, IteratorError>> {
if self.pos < self.items.len() {
let res = Ok(self.items[self.pos].clone());
self.pos += 1;
return Some(res);
}
None
}
fn resync(&mut self) {
self.pos = 0;
}
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}
unsafe impl<T> Send for Iterator<T> {}
unsafe extern "C" fn filter_trampoline<T>(value: gconstpointer, func: gconstpointer) -> i32
where
for<'a> T: FromValueOptional<'a> + 'static,
{
callback_guard!();
let value = value as *const gobject_ffi::GValue;
let func = func as *const gobject_ffi::GValue;
let func = gobject_ffi::g_value_get_boxed(func);
#[cfg_attr(feature = "cargo-clippy", allow(transmute_ptr_to_ref))]
let func: &&(Fn(T) -> bool + Send + Sync + 'static) = mem::transmute(func);
let value = &*(value as *const glib::Value);
let value = value.get::<T>().unwrap();
if func(value) {
0
} else {
-1
}
}
unsafe extern "C" fn filter_boxed_ref<T: 'static>(boxed: gpointer) -> gpointer {
callback_guard!();
let boxed = Arc::from_raw(boxed as *const (Box<Fn(T) -> bool + Send + Sync + 'static>));
let copy = Arc::clone(&boxed);
// Forget it and keep it alive, we will still need it later
let _ = Arc::into_raw(boxed);
Arc::into_raw(copy) as gpointer
}
unsafe extern "C" fn filter_boxed_unref<T: 'static>(boxed: gpointer) {
callback_guard!();
let _ = Arc::from_raw(boxed as *const (Box<Fn(T) -> bool + Send + Sync + 'static>));
}
unsafe extern "C" fn filter_boxed_get_type<T: StaticType + 'static>() -> glib_ffi::GType {
use std::sync::{Once, ONCE_INIT};
callback_guard!();
static mut TYPE: glib_ffi::GType = gobject_ffi::G_TYPE_INVALID;
static ONCE: Once = ONCE_INIT;
ONCE.call_once(|| {
let type_name = {
let mut idx = 0;
loop {
let type_name = CString::new(format!(
"GstRsIteratorFilterBoxed-{}-{}",
T::static_type().name(),
idx
)).unwrap();
if gobject_ffi::g_type_from_name(type_name.as_ptr()) == gobject_ffi::G_TYPE_INVALID
{
break type_name;
}
idx += 1;
}
};
TYPE = gobject_ffi::g_boxed_type_register_static(
type_name.as_ptr(),
Some(filter_boxed_ref::<T>),
Some(filter_boxed_unref::<T>),
);
});
TYPE
}
unsafe extern "C" fn find_trampoline<T>(value: gconstpointer, func: gconstpointer) -> i32
where
for<'a> T: FromValueOptional<'a> + 'static,
{
callback_guard!();
let value = value as *const gobject_ffi::GValue;
let func = func as *const &mut (FnMut(T) -> bool);
let value = &*(value as *const glib::Value);
let value = value.get::<T>().unwrap();
if (*func)(value) {
0
} else {
-1
}
}
unsafe extern "C" fn foreach_trampoline<T>(value: *const gobject_ffi::GValue, func: gpointer)
where
for<'a> T: FromValueOptional<'a> + 'static,
{
callback_guard!();
let func = func as *const &mut (FnMut(T));
let value = &*(value as *const glib::Value);
let value = value.get::<T>().unwrap();
(*func)(value);
}
unsafe extern "C" fn fold_trampoline<T, U>(
value: *const gobject_ffi::GValue,
ret: *mut gobject_ffi::GValue,
func: gpointer,
) -> glib_ffi::gboolean
where
for<'a> T: FromValueOptional<'a> + 'static,
{
callback_guard!();
let func = func as *const &mut (FnMut(U, T) -> Result<U, U>);
let value = &*(value as *const glib::Value);
let value = value.get::<T>().unwrap();
let accum = &mut *(gobject_ffi::g_value_get_pointer(ret) as *mut Option<U>);
match (*func)(accum.take().unwrap(), value) {
Ok(next_accum) => {
*accum = Some(next_accum);
glib_ffi::GTRUE
}
Err(next_accum) => {
*accum = Some(next_accum);
glib_ffi::GFALSE
}
}
}
impl<T: StaticType + 'static> Clone for Iterator<T> {
fn clone(&self) -> Self {
unsafe { from_glib_full(ffi::gst_iterator_copy(self.to_glib_none().0)) }
}
}
impl<T> Drop for Iterator<T> {
fn drop(&mut self) {
if !self.borrowed {
unsafe {
ffi::gst_iterator_free(self.iter);
}
}
}
}
impl<T> glib::types::StaticType for Iterator<T> {
fn static_type() -> glib::types::Type {
unsafe { glib::translate::from_glib(ffi::gst_iterator_get_type()) }
}
}
#[doc(hidden)]
impl<'a, T: StaticType> glib::value::FromValueOptional<'a> for Iterator<T> {
unsafe fn from_value_optional(value: &glib::Value) -> Option<Self> {
Option::<Iterator<T>>::from_glib_none(
gobject_ffi::g_value_get_boxed(value.to_glib_none().0) as *mut ffi::GstIterator,
)
}
}
#[doc(hidden)]
impl<T: 'static> glib::value::SetValue for Iterator<T> {
unsafe fn set_value(value: &mut glib::Value, this: &Self) {
gobject_ffi::g_value_set_boxed(
value.to_glib_none_mut().0,
glib::translate::ToGlibPtr::<*const ffi::GstIterator>::to_glib_none(this).0
as glib_ffi::gpointer,
)
}
}
#[doc(hidden)]
impl<T: 'static> glib::value::SetValueOptional for Iterator<T> {
unsafe fn set_value_optional(value: &mut glib::Value, this: Option<&Self>) {
gobject_ffi::g_value_set_boxed(
value.to_glib_none_mut().0,
glib::translate::ToGlibPtr::<*const ffi::GstIterator>::to_glib_none(&this).0
as glib_ffi::gpointer,
)
}
}
#[doc(hidden)]
impl<T> glib::translate::GlibPtrDefault for Iterator<T> {
type GlibType = *mut ffi::GstIterator;
}
#[doc(hidden)]
impl<'a, T: 'static> glib::translate::ToGlibPtr<'a, *const ffi::GstIterator> for Iterator<T> {
type Storage = &'a Iterator<T>;
fn to_glib_none(&'a self) -> glib::translate::Stash<'a, *const ffi::GstIterator, Self> {
glib::translate::Stash(self.iter, self)
}
fn to_glib_full(&self) -> *const ffi::GstIterator {
unimplemented!()
}
}
#[doc(hidden)]
impl<'a, T: 'static> glib::translate::ToGlibPtrMut<'a, *mut ffi::GstIterator> for Iterator<T> {
type Storage = &'a mut Iterator<T>;
#[inline]
fn to_glib_none_mut(
&'a mut self,
) -> glib::translate::StashMut<'a, *mut ffi::GstIterator, Self> {
glib::translate::StashMut(self.iter, self)
}
}
#[doc(hidden)]
impl<T: StaticType> glib::translate::FromGlibPtrNone<*const ffi::GstIterator> for Iterator<T> {
#[inline]
unsafe fn from_glib_none(ptr: *const ffi::GstIterator) -> Self {
assert_ne!(
gobject_ffi::g_type_is_a((*ptr).type_, T::static_type().to_glib()),
glib_ffi::GFALSE
);
from_glib_full(ffi::gst_iterator_copy(ptr))
}
}
#[doc(hidden)]
impl<T: StaticType> glib::translate::FromGlibPtrNone<*mut ffi::GstIterator> for Iterator<T> {
#[inline]
unsafe fn from_glib_none(ptr: *mut ffi::GstIterator) -> Self {
assert_ne!(
gobject_ffi::g_type_is_a((*ptr).type_, T::static_type().to_glib()),
glib_ffi::GFALSE
);
from_glib_full(ffi::gst_iterator_copy(ptr))
}
}
#[doc(hidden)]
impl<T: StaticType> glib::translate::FromGlibPtrBorrow<*mut ffi::GstIterator> for Iterator<T> {
#[inline]
unsafe fn from_glib_borrow(ptr: *mut ffi::GstIterator) -> Self {
assert_ne!(
gobject_ffi::g_type_is_a((*ptr).type_, T::static_type().to_glib()),
glib_ffi::GFALSE
);
Self {
iter: ptr,
borrowed: true,
phantom: PhantomData,
}
}
}
#[doc(hidden)]
impl<T: StaticType> glib::translate::FromGlibPtrFull<*mut ffi::GstIterator> for Iterator<T> {
#[inline]
unsafe fn from_glib_full(ptr: *mut ffi::GstIterator) -> Self {
assert_ne!(
gobject_ffi::g_type_is_a((*ptr).type_, T::static_type().to_glib()),
glib_ffi::GFALSE
);
Self {
iter: ptr,
borrowed: false,
phantom: PhantomData,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_vec() {
::init().unwrap();
let vec = vec![1i32, 2, 3];
let mut it = Iterator::from_vec(vec);
let val = it.next().unwrap();
assert_eq!(val, Ok(1));
let val = it.next().unwrap();
assert_eq!(val, Ok(2));
let val = it.next().unwrap();
assert_eq!(val, Ok(3));
assert!(it.next().is_none());
let vec = vec![1i32, 2, 3];
let it = Iterator::from_vec(vec);
let vals: Vec<_> = it.map(|v| v.unwrap()).collect();
assert_eq!(vals, [1, 2, 3]);
let vec = vec![1i32, 2, 3];
let mut it = Iterator::from_vec(vec);
let mut vals = Vec::new();
while let Some(res) = it.next() {
match res {
Ok(v) => vals.push(v),
_ => unreachable!(),
}
}
assert_eq!(vals, [1, 2, 3]);
let vec = vec![1i32, 2, 3];
let it = Iterator::from_vec(vec);
let mut vals = Vec::new();
for v in it {
vals.push(v.unwrap());
}
assert_eq!(vals, [1, 2, 3]);
}
#[test]
fn test_filter() {
::init().unwrap();
let vec = vec![1i32, 2, 3];
let it = Iterator::from_vec(vec).filter(|val| val % 2 == 1);
let vals: Vec<_> = it.map(|v| v.unwrap()).collect();
assert_eq!(vals, [1, 3]);
}
#[test]
fn test_find() {
::init().unwrap();
// Our find
let vec = vec![1i32, 2, 3];
let val = Iterator::from_vec(vec).find_simple(|val| val == 2);
assert_eq!(val.unwrap(), 2);
// Find from std::iter::Iterator
let vec = vec![1i32, 2, 3];
let val = Iterator::from_vec(vec).find(|val| val.unwrap() == 2);
assert_eq!(val.unwrap(), Ok(2));
}
#[test]
fn test_foreach() {
::init().unwrap();
let vec = vec![1i32, 2, 3];
let mut sum = 0;
let res = Iterator::from_vec(vec).foreach(|val| sum += val);
assert_eq!(res, Ok(()));
assert_eq!(sum, 6);
}
#[test]
fn test_fold() {
::init().unwrap();
// Our fold
let vec = vec![1i32, 2, 3];
let res = Iterator::from_vec(vec).fold_with_early_exit(0, |mut sum, val| {
sum += val;
Ok(sum)
});
assert_eq!(res.unwrap(), 6);
// Fold from std::iter::Iterator
let vec = vec![1i32, 2, 3];
let res = Iterator::from_vec(vec).fold(0, |mut sum, val| {
sum += val.unwrap();
sum
});
assert_eq!(res, 6);
}
}