mlt-core 0.9.2

MapLibre Tile library code
Documentation 
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

use std::convert::Infallible;
use std::num::TryFromIntError;

use num_enum::TryFromPrimitiveError;

use crate::decoder::{
    GeometryType, LogicalEncoding, LogicalTechnique, PhysicalEncoding, StreamType,
};
use crate::utils::AsUsize;

pub type MltResult<T> = Result<T, MltError>;
pub(crate) type MltRefResult<'a, T> = Result<(&'a [u8], T), MltError>;

#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum MltError {
    #[error("cannot decode {0} as {1}")]
    DataWidthMismatch(&'static str, &'static str),
    #[error("dictionary index {0} out of bounds (len={1})")]
    DictIndexOutOfBounds(u32, usize),
    #[error("duplicate value found where unique required")]
    DuplicateValue,
    #[error("Integer overflow")]
    IntegerOverflow,
    #[error("missing geometry column in feature table")]
    MissingGeometry,
    #[error("missing string stream: {0}")]
    MissingStringStream(&'static str),
    #[error("multiple geometry columns found (only one allowed)")]
    MultipleGeometryColumns,
    #[error("multiple ID columns found (only one allowed)")]
    MultipleIdColumns,
    #[error("varint uses more bytes than necessary (non-canonical encoding)")]
    NonCanonicalVarInt,
    #[error("{0} is not decoded")]
    NotDecoded(&'static str),
    #[error("decoded data is not in encoded form")]
    NotEncoded,
    #[error("error parsing column type: code={0}")]
    ParsingColumnType(u8),
    #[error("error parsing logical technique: code={0}")]
    ParsingLogicalTechnique(u8),
    #[error("error parsing physical encoding: code={0}")]
    ParsingPhysicalEncoding(u8),
    #[error("error parsing stream type: code={0}")]
    ParsingStreamType(u8),
    #[error("found {0} bytes after the expected end of layer")]
    TrailingLayerData(usize),
    #[error("unexpected end of input (unable to take {0} bytes)")]
    UnableToTake(u32),
    #[error("unexpected stream type {0:?}")]
    UnexpectedStreamType(StreamType),
    #[error("unexpected stream type {0:?}, expected {1} for {2}")]
    UnexpectedStreamType2(StreamType, &'static str, &'static str),
    #[error("unsupported logical encoding {0:?} for {1}")]
    UnsupportedLogicalEncoding(LogicalEncoding, &'static str),
    #[error("invalid combination of logical encodings: {0:?} + {1:?}")]
    InvalidLogicalEncodings(LogicalTechnique, LogicalTechnique),
    #[error("layer has zero size")]
    ZeroLayerSize,
    #[error("The encoder used to optimise data is incompatible")]
    BadEncoderDataCombination,
    #[error("StagedLayer::encode_explicit requires Encoder.explicit to be Some(_)")]
    MissingExplicitEncoder,

    // Wire/codec decoding (bytes → primitives)
    #[error("buffer underflow: needed {0} bytes, but only {1} remain")]
    BufferUnderflow(u32, usize),
    #[error("FastPFor decode failed: expected={0} got={1}")]
    FastPforDecode(u32, usize),
    #[error("invalid RLE run length (cannot convert to usize): value={0}")]
    RleRunLenInvalid(i128),

    // Structural constraints (lengths, counts, shapes)
    #[error("geometry requires at least 1 stream, got 0")]
    GeometryWithoutStreams,
    #[error("FastPFor data byte length expected multiple of 4, got {0}")]
    InvalidFastPforByteLength(usize),
    #[error("vec2 delta stream size expected to be non-empty and multiple of 2, got {0}")]
    InvalidPairStreamSize(usize),
    #[error("decodable stream size expected {1}, got {0}")]
    InvalidDecodingStreamSize(usize, usize),
    #[error("IDs missing for encoding (expected Some IDs, got None)")]
    IdsMissingForEncoding,
    #[error("missing struct encoder for struct")]
    MissingStructEncoderForStruct,
    #[error("previous decode/parsing attempt failed")]
    PriorParseFailure,
    #[error("presence stream has {0} bits set but {1} values provided")]
    PresenceValueCountMismatch(usize, usize),
    #[error("need to encode before being able to write")]
    NeedsEncodingBeforeWriting,
    #[error("memory limit exceeded: limit={limit}, used={used}, requested={requested}")]
    MemoryLimitExceeded {
        limit: u32,
        used: u32,
        requested: u32,
    },
    #[error("not implemented: {0}")]
    NotImplemented(&'static str),
    #[error("unsupported property value and encoder combination: {0:?} + {1:?}")]
    UnsupportedPropertyEncoderCombination(&'static str, &'static str),
    #[error("mixed property types are not allowed in column {0} ({1})")]
    MixedPropertyTypes(usize, String),
    #[error("shared dictionary requires at least 2 streams, got {0}")]
    SharedDictRequiresStreams(usize),
    #[error("unsupported string stream count (expected between 2 and 5): {0}")]
    UnsupportedStringStreamCount(usize),
    #[error("Structs are not allowed to be optional")]
    TriedToEncodeOptionalStruct,
    #[error(
        "encoding instruction count mismatch: expected {input_len} instructions for {input_len} properties, got {config_len}"
    )]
    EncodingInstructionCountMismatch { input_len: usize, config_len: usize },
    #[error("struct child data streams expected exactly 1 value, got {0}")]
    UnexpectedStructChildCount(u32),
    // Note that {expected}+1 is allowed for the legacy Java encoder bug
    #[error("SharedDict stream count is {actual}, expected {expected}")]
    InvalidSharedDictStreamCount { actual: u32, expected: u32 },
    #[error("unsupported physical encoding: {0}")]
    UnsupportedPhysicalEncoding(&'static str),
    #[error("unsupported physical encoding: {0:?} for {1}")]
    UnsupportedPhysicalEncodingForType(PhysicalEncoding, &'static str),
    #[error(
        "Extent {extent} cannot be encoded to morton due to morton allowing max. 16 bits, but {required_bits} would be required"
    )]
    VertexMortonNotCompatibleWithExtent { extent: u32, required_bits: u32 },
    #[error("Morton stream uses {0} bits, but at most 16 bits are supported")]
    InvalidMortonBits(u32),

    // Geometry decode errors (field = variable name, geom_type for context)
    #[error("MVT error: {0}")]
    BadMvtGeometry(&'static str),
    #[error("geometry[{0}]: index out of bounds")]
    GeometryIndexOutOfBounds(usize),
    #[error("geometry[{index}]: {field}[{idx}] out of bounds (len={len})")]
    GeometryOutOfBounds {
        index: usize,
        field: &'static str,
        idx: usize,
        len: usize,
    },
    #[error("geometry[{index}]: vertex {vertex} out of bounds (count={count})")]
    GeometryVertexOutOfBounds {
        index: usize,
        vertex: usize,
        count: usize,
    },
    #[error("geometry[{0}]: {1} requires geometry_offsets")]
    NoGeometryOffsets(usize, GeometryType),
    #[error("geometry[{0}]: {1} requires part_offsets")]
    NoPartOffsets(usize, GeometryType),
    #[error("geometry[{0}]: {1} requires ring_offsets")]
    NoRingOffsets(usize, GeometryType),
    #[error("geometry[{0}]: unexpected offset combination for {1}")]
    UnexpectedOffsetCombination(usize, GeometryType),

    #[error("FastPFor error: {0}")]
    FastPfor(#[from] fastpfor::FastPForError),
    #[error(transparent)]
    Io(#[from] std::io::Error),
    #[error("Serde JSON error: {0}")]
    SerdeJsonError(#[from] serde_json::Error),
    #[error("integer conversion error: {0}")]
    TryFromIntError(#[from] TryFromIntError),
    #[error("num_enum conversion error: {0}")]
    TryFromPrimitive(#[from] TryFromPrimitiveError<GeometryType>),
    #[error("UTF-8 decode error: {0}")]
    Utf8(#[from] std::str::Utf8Error),
    #[error("UTF-8 decode error: {0}")]
    FromUtf8(#[from] std::string::FromUtf8Error),
    #[error("MVT parse error: {0}")]
    MvtParse(String),
    #[error("MVT write error: {0}")]
    MvtWrite(#[from] mvt::Error),
}

impl From<Infallible> for MltError {
    fn from(_: Infallible) -> Self {
        unreachable!()
    }
}

// `mvt_reader::error::ParserError` carries `Box<dyn Error>` (no `Send + Sync`),
// which would make `MltError` non-Send/Sync via `#[from]`. Stringify at the
// boundary so the rest of `MltError` stays auto-trait-clean.
impl From<mvt_reader::error::ParserError> for MltError {
    fn from(e: mvt_reader::error::ParserError) -> Self {
        Self::MvtParse(e.to_string())
    }
}

impl From<MltError> for std::io::Error {
    fn from(value: MltError) -> Self {
        match value {
            MltError::Io(e) => e,
            other => Self::other(other),
        }
    }
}

pub(crate) trait AsMltError<T> {
    fn or_overflow(&self) -> MltResult<T>;
}

impl<T: Copy> AsMltError<T> for Option<T> {
    #[inline]
    fn or_overflow(&self) -> MltResult<T> {
        self.ok_or(MltError::IntegerOverflow)
    }
}

impl AsMltError<u32> for Result<u32, TryFromIntError> {
    #[inline]
    fn or_overflow(&self) -> MltResult<u32> {
        self.map_err(|_| MltError::IntegerOverflow)
    }
}

#[inline]
pub(crate) fn fail_if_invalid_stream_size<T: AsUsize>(actual: T, expected: T) -> MltResult<()> {
    if actual == expected {
        Ok(())
    } else {
        Err(MltError::InvalidDecodingStreamSize(
            actual.as_usize(),
            expected.as_usize(),
        ))
    }
}