1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
// Take a look at the license at the top of the repository in the LICENSE file.

use crate::Caps;
use crate::Plugin;
use crate::Rank;
use crate::TypeFindFactory;
use crate::TypeFindProbability;

use glib::translate::*;
use std::ptr;
use std::slice;

#[repr(transparent)]
#[derive(Debug)]
pub struct TypeFind(ffi::GstTypeFind);

pub trait TypeFindImpl {
    fn peek(&mut self, offset: i64, size: u32) -> Option<&[u8]>;
    fn suggest(&mut self, probability: TypeFindProbability, caps: &Caps);
    #[doc(alias = "get_length")]
    fn length(&self) -> Option<u64> {
        None
    }
}

impl TypeFind {
    pub fn register<F>(
        plugin: Option<&Plugin>,
        name: &str,
        rank: Rank,
        extensions: Option<&str>,
        possible_caps: Option<&Caps>,
        func: F,
    ) -> Result<(), glib::error::BoolError>
    where
        F: Fn(&mut TypeFind) + Send + Sync + 'static,
    {
        assert_initialized_main_thread!();
        unsafe {
            let func: Box<F> = 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.into_glib() as u32,
                Some(type_find_trampoline::<F>),
                extensions.to_glib_none().0,
                possible_caps.to_glib_none().0,
                func as *mut _,
                Some(type_find_closure_drop::<F>),
            );

            glib::result_from_gboolean!(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.into_glib() as u32,
                caps.to_glib_none().0,
            );
        }
    }

    #[doc(alias = "get_length")]
    pub fn length(&mut self) -> Option<u64> {
        unsafe {
            let len = ffi::gst_type_find_get_length(&mut self.0);
            if len == 0 {
                None
            } else {
                Some(len)
            }
        }
    }
}

impl TypeFindFactory {
    /// Calls the `GstTypeFindFunction` associated with this factory.
    /// ## `find`
    /// a properly setup [`crate::TypeFind`] entry. The get_data
    ///  and suggest_type members must be set.
    pub fn call_function(&self, find: &mut dyn TypeFindImpl) {
        unsafe {
            let find_ptr = &find as *const &mut dyn 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<F: Fn(&mut TypeFind) + Send + Sync + 'static>(
    find: *mut ffi::GstTypeFind,
    user_data: glib::ffi::gpointer,
) {
    let func: &F = &*(user_data as *const F);
    func(&mut *(find as *mut TypeFind));
}

unsafe extern "C" fn type_find_closure_drop<F: Fn(&mut TypeFind) + Send + Sync + 'static>(
    data: glib::ffi::gpointer,
) {
    Box::<F>::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 dyn TypeFindImpl = &mut *(data as *mut &mut dyn 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 dyn TypeFindImpl = &mut *(data as *mut &mut dyn 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 dyn TypeFindImpl = &mut *(data as *mut &mut dyn TypeFindImpl);
    find.length().unwrap_or(u64::MAX)
}

#[derive(Debug)]
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> {
        assert_initialized_main_thread!();
        SliceTypeFind {
            probability: None,
            caps: None,
            data,
        }
    }

    pub fn run(&mut self) {
        let factories = TypeFindFactory::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>) {
        assert_initialized_main_thread!();
        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 length(&self) -> Option<u64> {
        Some(self.data.as_ref().len() as u64)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_typefind_call_function() {
        crate::init().unwrap();

        let xml_factory = TypeFindFactory::list()
            .iter()
            .cloned()
            .find(|f| {
                f.caps()
                    .map(|c| {
                        c.structure(0)
                            .map(|s| s.name() == "application/xml")
                            .unwrap_or(false)
                    })
                    .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() {
        crate::init().unwrap();

        TypeFind::register(
            None,
            "test_typefind",
            crate::Rank::Primary,
            None,
            Some(&Caps::new_simple("test/test", &[])),
            |typefind| {
                assert_eq!(typefind.length(), Some(8));
                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);
    }
}