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

use crate::{
    PartitionBuffer, PartitionEntry, PartitionError, PartitionReaderState, PartitionTable,
    PartitionWriterState,
};
use core::{mem::MaybeUninit, ops::Deref};
use embedded_storage::{ReadStorage, Storage};

/// Error type for embedded storage operations
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum StorageOpError<S: ReadStorage> {
    /// Partition specific error
    PartitionError(PartitionError),
    /// Storage specific error
    StorageError(S::Error),
}

impl<S: ReadStorage> From<PartitionError> for StorageOpError<S> {
    fn from(error: PartitionError) -> Self {
        Self::PartitionError(error)
    }
}

impl PartitionTable {
    /// Get iterator over partitions from table
    ///
    /// If `md5` feature isn't enabled `calc_md5` argument will be ignored.
    pub fn iter_storage<'s, S>(
        &self,
        storage: &'s mut S,
        calc_md5: bool,
    ) -> PartitionStorageIter<'s, S>
    where
        S: ReadStorage,
    {
        PartitionStorageIter {
            storage,
            state: PartitionReaderState::new(self.addr, self.size, calc_md5),
            buffer: MaybeUninit::uninit(),
        }
    }

    /// Read partitions from table
    ///
    /// The `check_md5` argument means following:
    /// - None - ignore MD5 checksum
    /// - Some(false) - check MD5 when found (optional MD5)
    /// - Some(true) - MD5 checksum is mandatory
    ///
    /// If `md5` feature isn't enabled `check_md5` argument will be ignored.
    #[cfg(feature = "embedded-storage")]
    pub fn read_storage<S, T>(
        &self,
        storage: &mut S,
        check_md5: Option<bool>,
    ) -> Result<T, StorageOpError<S>>
    where
        S: ReadStorage,
        T: FromIterator<PartitionEntry>,
    {
        let mut iter = self.iter_storage(storage, check_md5.is_some());
        let result = (&mut iter).collect::<Result<_, _>>()?;

        #[cfg(feature = "md5")]
        if let Some(mandatory_md5) = check_md5 {
            if !iter.check_md5().unwrap_or(!mandatory_md5) {
                return Err(PartitionError::InvalidMd5.into());
            }
        }

        Ok(result)
    }

    /// Write partitions into table
    ///
    /// If `md5` feature isn't enabled `write_md5` argument will be ignored.
    #[cfg(feature = "embedded-storage")]
    pub fn write_storage<S>(
        &self,
        storage: &mut S,
        partitions: impl IntoIterator<Item = impl AsRef<PartitionEntry>>,
        write_md5: bool,
    ) -> Result<usize, StorageOpError<S>>
    where
        S: Storage,
    {
        let mut data = MaybeUninit::<PartitionBuffer>::uninit();
        let mut state = PartitionWriterState::new(self.addr, self.size, write_md5);

        for partition in partitions {
            if state.is_done() {
                return Err(PartitionError::TooManyData.into());
            }

            state.write(unsafe { data.assume_init_mut() }, partition)?;

            storage
                .write(state.offset(), unsafe { data.assume_init_ref() })
                .map_err(StorageOpError::StorageError)?;
        }

        #[cfg(feature = "md5")]
        if write_md5 {
            if state.is_done() {
                return Err(PartitionError::TooManyData.into());
            }

            state.write_md5(unsafe { data.assume_init_mut() })?;

            storage
                .write(state.offset(), unsafe { data.assume_init_ref() })
                .map_err(StorageOpError::StorageError)?;
        }

        Ok((state.offset() - self.addr) as usize)
    }
}

/// Iterator over embedded partition table
pub struct PartitionStorageIter<'s, S> {
    storage: &'s mut S,
    state: PartitionReaderState,
    buffer: MaybeUninit<PartitionBuffer>,
}

impl<'s, S> PartitionStorageIter<'s, S> {
    /// Read next partition entry
    pub fn next_partition(&mut self) -> Result<PartitionEntry, StorageOpError<S>>
    where
        S: ReadStorage,
    {
        if self.state.is_done() {
            return Err(StorageOpError::PartitionError(
                PartitionError::NotEnoughData,
            ));
        }

        if let Err(error) = self.storage.read(self.state.offset(), unsafe {
            self.buffer.assume_init_mut()
        }) {
            return Err(StorageOpError::StorageError(error));
        }

        self.state
            .read(unsafe { self.buffer.assume_init_ref() })
            .map_err(From::from)
    }
}

impl<'s, S> Deref for PartitionStorageIter<'s, S> {
    type Target = PartitionReaderState;

    fn deref(&self) -> &Self::Target {
        &self.state
    }
}

impl<'s, S> Iterator for PartitionStorageIter<'s, S>
where
    S: ReadStorage,
{
    type Item = Result<PartitionEntry, StorageOpError<S>>;

    fn next(&mut self) -> Option<Self::Item> {
        self.next_partition()
            .map(Some)
            .or_else(|error| {
                if matches!(
                    error,
                    StorageOpError::PartitionError(PartitionError::NotEnoughData)
                ) {
                    Ok(None)
                } else {
                    Err(error)
                }
            })
            .transpose()
    }
}