stdweb/webapi/
blob.rs

1use std::ops::{RangeBounds, Bound};
2
3use webcore::value::Reference;
4use webcore::try_from::TryInto;
5use webcore::reference_type::ReferenceType;
6use webcore::number::Number;
7use webcore::optional_arg::OptionalArg;
8
9// https://w3c.github.io/FileAPI/#ref-for-dfn-slice
10fn slice_blob< T, U >( blob: &T, range: U, content_type: Option< &str > ) -> Blob
11    where T: IBlob, U: RangeBounds< u64 >
12{
13    let start: Number = match range.start_bound() {
14        Bound::Included(&n) => n,
15        Bound::Excluded(&n) => n + 1,
16        Bound::Unbounded => 0
17    }.try_into().unwrap();
18
19    let end: OptionalArg< Number > = match range.end_bound() {
20        Bound::Included(&n) => Some(n + 1),
21        Bound::Excluded(&n) => Some(n),
22        Bound::Unbounded => None
23    }.try_into().unwrap();
24
25    let content_type: OptionalArg< &str > = content_type.into();
26    let reference = blob.as_ref();
27    js! (
28        return @{reference}.slice(@{start}, @{end}, @{content_type});
29    ).try_into().unwrap()
30}
31
32/// A blob object represents a file-like object of immutable, raw data.
33/// Blobs represent data that isn't necessarily in a JavaScript-native format.
34///
35/// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob)
36// https://w3c.github.io/FileAPI/#dfn-Blob
37pub trait IBlob: ReferenceType {
38    /// The size, in bytes, of the data contained in the Blob object.
39    ///
40    /// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob/size)
41    // https://w3c.github.io/FileAPI/#ref-for-dfn-size%E2%91%A0
42    fn len( &self ) -> u64 {
43        let reference = self.as_ref();
44        let length: u64 = js!( return @{reference}.size; ).try_into().unwrap();
45        length
46    }
47
48    /// A string indicating the MIME type of the data contained in the `Blob`.
49    ///
50    /// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob/type)
51    // https://w3c.github.io/FileAPI/#ref-for-dfn-type%E2%91%A0
52    fn mime( &self ) -> Option< String > {
53        let reference = self.as_ref();
54        let mime: String = js!( return @{reference}.type; ).try_into().unwrap();
55        if mime.is_empty() {
56            None
57        } else {
58            Some( mime )
59        }
60    }
61
62    /// Create a new `Blob` object containing the data in the specified range of bytes of the
63    /// source `Blob`.
64    /// 
65    /// See also [slice_with_content_type](IBlob::slice_with_content_type).
66    /// 
67    /// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob/slice)
68    fn slice< T >( &self, range: T ) -> Blob
69        where T: RangeBounds<u64>
70    {
71        slice_blob(self, range, None)
72    }
73
74    /// [slice](IBlob::slice) `Blob` with the provided `content_type`.
75    fn slice_with_content_type< T >( &self, range: T, content_type: &str ) -> Blob
76        where T: RangeBounds<u64>
77    {
78        slice_blob(self, range, Some(content_type))
79    }
80}
81
82/// A reference to a JavaScript object which implements the [IBlob](trait.IBlob.html)
83/// interface.
84///
85/// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob)
86// https://w3c.github.io/FileAPI/#dfn-Blob
87#[derive(Clone, Debug, PartialEq, Eq, ReferenceType)]
88#[reference(instance_of = "Blob")]
89pub struct Blob( Reference );
90
91impl IBlob for Blob {}
92
93impl Blob {
94    /// Creates a new `Blob`.
95    ///
96    /// [(JavaScript docs)](https://developer.mozilla.org/en-US/docs/Web/API/Blob/Blob)
97    // https://w3c.github.io/FileAPI/#constructorBlob
98    pub fn new() -> Self {
99        js! (
100            return new Blob();
101        ).try_into().unwrap()
102    }
103}
stdweb/webapi/blob.rs

stdweb/webapi/
blob.rs
