skia_safe/core/
data.rs

1use std::{
2    ffi::{CStr, CString},
3    fmt, io,
4    ops::Deref,
5    path::Path,
6};
7
8use skia_bindings::{self as sb, SkData};
9
10use crate::{interop::RustStream, prelude::*};
11
12pub type Data = RCHandle<SkData>;
13unsafe_send_sync!(Data);
14require_base_type!(SkData, sb::SkNVRefCnt);
15
16impl NativeRefCounted for SkData {
17    fn _ref(&self) {
18        unsafe { sb::C_SkData_ref(self) }
19    }
20
21    fn _unref(&self) {
22        unsafe { sb::C_SkData_unref(self) }
23    }
24
25    fn unique(&self) -> bool {
26        unsafe { sb::C_SkData_unique(self) }
27    }
28}
29
30impl Deref for Data {
31    type Target = [u8];
32    fn deref(&self) -> &Self::Target {
33        self.as_bytes()
34    }
35}
36
37impl PartialEq for Data {
38    // Although there is an implementation in SkData for equality testing, we
39    // prefer to stay on the Rust side for that.
40    fn eq(&self, other: &Self) -> bool {
41        self.deref() == other.deref()
42    }
43}
44
45impl fmt::Debug for Data {
46    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
47        f.debug_struct("Data").field("size", &self.size()).finish()
48    }
49}
50
51impl Data {
52    pub fn size(&self) -> usize {
53        self.native().fSize
54    }
55
56    pub fn is_empty(&self) -> bool {
57        self.size() == 0
58    }
59
60    pub fn as_bytes(&self) -> &[u8] {
61        unsafe { safer::from_raw_parts(self.native().fPtr as _, self.size()) }
62    }
63
64    // TODO:
65    // pub unsafe fn writable_data(&mut self) -> &mut [u8]
66
67    pub fn copy_range(&self, offset: usize, buffer: &mut [u8]) -> &Self {
68        buffer.copy_from_slice(&self.as_bytes()[offset..offset + buffer.len()]);
69        self
70    }
71
72    // TODO: rename to copy_from() ? or from_bytes()?
73    pub fn new_copy(data: &[u8]) -> Self {
74        Data::from_ptr(unsafe { sb::C_SkData_MakeWithCopy(data.as_ptr() as _, data.len()) })
75            .unwrap()
76    }
77
78    /// Constructs Data from a given byte slice without copying it.
79    ///
80    /// Users must make sure that the underlying slice will outlive the lifetime of the Data.
81    #[allow(clippy::missing_safety_doc)]
82    pub unsafe fn new_bytes(data: &[u8]) -> Self {
83        Data::from_ptr(sb::C_SkData_MakeWithoutCopy(data.as_ptr() as _, data.len())).unwrap()
84    }
85
86    #[allow(clippy::missing_safety_doc)]
87    pub unsafe fn new_uninitialized(length: usize) -> Data {
88        Data::from_ptr(sb::C_SkData_MakeUninitialized(length)).unwrap()
89    }
90
91    pub fn new_zero_initialized(length: usize) -> Data {
92        Data::from_ptr(unsafe { sb::C_SkData_MakeZeroInitialized(length) }).unwrap()
93    }
94
95    // TODO: use Range as stand in for offset / length?
96    pub fn new_subset(data: &Data, offset: usize, length: usize) -> Data {
97        Data::from_ptr(unsafe { sb::C_SkData_MakeSubset(data.native(), offset, length) }).unwrap()
98    }
99
100    /// Constructs Data from a copy of a &str.
101    ///
102    /// Functions that use `Data` as a string container usually expect it to contain a c-string
103    /// including the terminating 0 byte, so this function converts the Rust `str` to a `CString`
104    /// and calls [`Self::new_cstr()`].
105    pub fn new_str(str: impl AsRef<str>) -> Data {
106        Self::new_cstr(&CString::new(str.as_ref()).unwrap())
107    }
108
109    /// Constructs Data from a &CStr by copying its contents.
110    pub fn new_cstr(cstr: &CStr) -> Data {
111        Data::from_ptr(unsafe { sb::C_SkData_MakeWithCString(cstr.as_ptr()) }).unwrap()
112    }
113
114    /// Create a new `Data` referencing the file with the specified path. If the file cannot be
115    /// opened, the path contains 0 bytes, or the path is not valid UTF-8, this returns `None`.
116    ///
117    /// This function opens the file as a memory mapped file for the lifetime of `Data` returned.
118    pub fn from_filename(path: impl AsRef<Path>) -> Option<Self> {
119        let path = CString::new(path.as_ref().to_str()?).ok()?;
120        Data::from_ptr(unsafe { sb::C_SkData_MakeFromFileName(path.as_ptr()) })
121    }
122
123    // TODO: MakeFromFile (is there a way to wrap this safely?)
124
125    /// Attempt to read size bytes into a [`Data`]. If the read succeeds, return the data,
126    /// else return `None`. Either way the stream's cursor may have been changed as a result
127    /// of calling read().
128    pub fn from_stream(mut stream: impl io::Read, size: usize) -> Option<Self> {
129        let mut stream = RustStream::new(&mut stream);
130        Data::from_ptr(unsafe { sb::C_SkData_MakeFromStream(stream.stream_mut(), size) })
131    }
132
133    pub fn new_empty() -> Self {
134        Data::from_ptr(unsafe { sb::C_SkData_MakeEmpty() }).unwrap()
135    }
136}
137
138#[cfg(test)]
139mod tests {
140    use super::*;
141
142    impl RefCount for SkData {
143        fn ref_cnt(&self) -> usize {
144            self._base.ref_cnt()
145        }
146    }
147
148    #[test]
149    fn data_supports_equals() {
150        let x: &[u8] = &[1u8, 2u8, 3u8];
151        let d1 = Data::new_copy(x);
152        let d2 = Data::new_copy(x);
153        assert!(d1 == d2)
154    }
155
156    #[test]
157    fn from_stream_empty() {
158        let data = [];
159        let cursor = io::Cursor::new(data);
160        let data = Data::from_stream(cursor, 0).unwrap();
161        assert_eq!(data.len(), 0);
162    }
163
164    #[test]
165    fn from_stream() {
166        let data = [1u8];
167        let cursor = io::Cursor::new(data);
168        let data = Data::from_stream(cursor, 1).unwrap();
169        assert_eq!(data.len(), 1);
170        assert_eq!(data[0], 1u8);
171    }
172}
skia_safe/core/data.rs

skia_safe/core/
data.rs
