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

use libc::c_int;
use std::error::Error as StdError;
use std::ffi::CStr;
use std::os::raw::c_char;
use std::{fmt, result, str};

use ffi;

/// An LMDB error kind.
#[derive(Debug, Eq, PartialEq, Copy, Clone)]
pub enum Error {
    /// key/data pair already exists.
    KeyExist,
    /// key/data pair not found (EOF).
    NotFound,
    /// Requested page not found - this usually indicates corruption.
    PageNotFound,
    /// Located page was wrong type.
    Corrupted,
    /// Update of meta page failed or environment had fatal error.
    Panic,
    /// Environment version mismatch.
    VersionMismatch,
    /// File is not a valid LMDB file.
    Invalid,
    /// Environment mapsize reached.
    MapFull,
    /// Environment maxdbs reached.
    DbsFull,
    /// Environment maxreaders reached.
    ReadersFull,
    /// Too many TLS keys in use - Windows only.
    TlsFull,
    /// Txn has too many dirty pages.
    TxnFull,
    /// Cursor stack too deep - internal error.
    CursorFull,
    /// Page has not enough space - internal error.
    PageFull,
    /// Database contents grew beyond environment mapsize.
    MapResized,
    /// MDB_Incompatible: Operation and DB incompatible, or DB flags changed.
    Incompatible,
    /// Invalid reuse of reader locktable slot.
    BadRslot,
    /// Transaction cannot recover - it must be aborted.
    BadTxn,
    /// Unsupported size of key/DB name/data, or wrong DUP_FIXED size.
    BadValSize,
    /// The specified DBI was changed unexpectedly.
    BadDbi,
    /// Other error.
    Other(c_int),
}

impl Error {

    /// Converts a raw error code to an `Error`.
    pub fn from_err_code(err_code: c_int) -> Error {
        match err_code {
            ffi::MDB_KEYEXIST         => Error::KeyExist,
            ffi::MDB_NOTFOUND         => Error::NotFound,
            ffi::MDB_PAGE_NOTFOUND    => Error::PageNotFound,
            ffi::MDB_CORRUPTED        => Error::Corrupted,
            ffi::MDB_PANIC            => Error::Panic,
            ffi::MDB_VERSION_MISMATCH => Error::VersionMismatch,
            ffi::MDB_INVALID          => Error::Invalid,
            ffi::MDB_MAP_FULL         => Error::MapFull,
            ffi::MDB_DBS_FULL         => Error::DbsFull,
            ffi::MDB_READERS_FULL     => Error::ReadersFull,
            ffi::MDB_TLS_FULL         => Error::TlsFull,
            ffi::MDB_TXN_FULL         => Error::TxnFull,
            ffi::MDB_CURSOR_FULL      => Error::CursorFull,
            ffi::MDB_PAGE_FULL        => Error::PageFull,
            ffi::MDB_MAP_RESIZED      => Error::MapResized,
            ffi::MDB_INCOMPATIBLE     => Error::Incompatible,
            ffi::MDB_BAD_RSLOT        => Error::BadRslot,
            ffi::MDB_BAD_TXN          => Error::BadTxn,
            ffi::MDB_BAD_VALSIZE      => Error::BadValSize,
            ffi::MDB_BAD_DBI          => Error::BadDbi,
            other                     => Error::Other(other),
        }
    }

    /// Converts an `Error` to the raw error code.
    pub fn to_err_code(&self) -> c_int {
        match *self {
            Error::KeyExist        => ffi::MDB_KEYEXIST,
            Error::NotFound        => ffi::MDB_NOTFOUND,
            Error::PageNotFound    => ffi::MDB_PAGE_NOTFOUND,
            Error::Corrupted       => ffi::MDB_CORRUPTED,
            Error::Panic           => ffi::MDB_PANIC,
            Error::VersionMismatch => ffi::MDB_VERSION_MISMATCH,
            Error::Invalid         => ffi::MDB_INVALID,
            Error::MapFull         => ffi::MDB_MAP_FULL,
            Error::DbsFull         => ffi::MDB_DBS_FULL,
            Error::ReadersFull     => ffi::MDB_READERS_FULL,
            Error::TlsFull         => ffi::MDB_TLS_FULL,
            Error::TxnFull         => ffi::MDB_TXN_FULL,
            Error::CursorFull      => ffi::MDB_CURSOR_FULL,
            Error::PageFull        => ffi::MDB_PAGE_FULL,
            Error::MapResized      => ffi::MDB_MAP_RESIZED,
            Error::Incompatible    => ffi::MDB_INCOMPATIBLE,
            Error::BadRslot        => ffi::MDB_BAD_RSLOT,
            Error::BadTxn          => ffi::MDB_BAD_TXN,
            Error::BadValSize      => ffi::MDB_BAD_VALSIZE,
            Error::BadDbi          => ffi::MDB_BAD_DBI,
            Error::Other(err_code) => err_code,
        }
    }
}

impl fmt::Display for Error {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        write!(fmt, "{}", self.description())
    }
}

impl StdError for Error {
    fn description(&self) -> &str {
        unsafe {
            // This is safe since the error messages returned from mdb_strerror are static.
            let err: *const c_char = ffi::mdb_strerror(self.to_err_code()) as *const c_char;
            str::from_utf8_unchecked(CStr::from_ptr(err).to_bytes())
        }
    }
}

/// An LMDB result.
pub type Result<T> = result::Result<T, Error>;

pub fn lmdb_result(err_code: c_int) -> Result<()> {
    if err_code == ffi::MDB_SUCCESS {
        Ok(())
    } else {
        Err(Error::from_err_code(err_code))
    }
}

#[cfg(test)]
mod test {

    use std::error::Error as StdError;

    use super::*;

    #[test]
    fn test_description() {
        assert_eq!("Permission denied",
                   Error::from_err_code(13).description());
        assert_eq!("MDB_NOTFOUND: No matching key/data pair found",
                   Error::NotFound.description());
    }
}