Struct DbFlags

pub struct DbFlags(/* private fields */);

A set of database flags

Implementations

impl DbFlags

pub const DbReverseKey: Self

Keys are strings to be compared in reverse order, from the end of the strings to the beginning. By default, Keys are treated as strings and compared from beginning to end.

pub const DbAllowDups: Self

Duplicate keys may be used in the database. (Or, from another perspective, keys may have multiple data items, stored in sorted order.) By default keys must be unique and may have only a single data item.

pub const DbIntKey: Self

Keys are binary integers in native byte order. Setting this option requires all keys to be the same size, typically sizeof(int) or sizeof(size_t).

pub const DbDupFixed: Self

This flag may only be used in combination with ffi::MDB_DUPSORT. This option tells the library that the data items for this database are all the same size, which allows further optimizations in storage and retrieval. When all data items are the same size, the ffi::MDB_GET_MULTIPLE and ffi::MDB_NEXT_MULTIPLE cursor operations may be used to retrieve multiple items at once.

pub const DbAllowIntDups: Self

This option specifies that duplicate data items are also integers, and should be sorted as such.

pub const DbReversedDups: Self

This option specifies that duplicate data items should be compared as strings in reverse order.

pub const DbCreate: Self

Create the named database if it doesn’t exist. This option is not allowed in a read-only transaction or a read-only environment.

impl DbFlags

pub const fn empty() -> Self

Get a flags value with all bits unset.

Examples found in repository

examples/simple.rs (line 8)

fn main() {
    let env = EnvBuilder::new().open("test-lmdb", 0o777).unwrap();

    let db_handle = env.get_default_db(DbFlags::empty()).unwrap();
    let txn = env.new_transaction().unwrap();
    {
        let db = txn.bind(&db_handle); // get a database bound to this transaction

        let pairs = vec![("Albert", "Einstein",),
                         ("Joe", "Smith",),
                         ("Jack", "Daniels")];

        for &(name, surname) in pairs.iter() {
            db.set(&surname, &name).unwrap();
        }
    }

    // Note: `commit` is choosen to be explicit as
    // in case of failure it is responsibility of
    // the client to handle the error
    match txn.commit() {
        Err(_) => panic!("failed to commit!"),
        Ok(_) => ()
    }

    let reader = env.get_reader().unwrap();
    let db = reader.bind(&db_handle);
    let name = db.get::<&str>(&"Smith").unwrap();
    println!("It's {} Smith", name);
}

pub const fn all() -> Self

Get a flags value with all known bits set.

pub const fn bits(&self) -> c_uint

Get the underlying bits value.

The returned value is exactly the bits set in this flags value.

pub const fn from_bits(bits: c_uint) -> Option<Self>

Convert from a bits value.

This method will return None if any unknown bits are set.

pub const fn from_bits_truncate(bits: c_uint) -> Self

Convert from a bits value, unsetting any unknown bits.

pub const fn from_bits_retain(bits: c_uint) -> Self

Convert from a bits value exactly.

pub fn from_name(name: &str) -> Option<Self>

Get a flags value with the bits of a flag with the given name set.

This method will return None if name is empty or doesn’t correspond to any named flag.

pub const fn is_empty(&self) -> bool

Whether all bits in this flags value are unset.

pub const fn is_all(&self) -> bool

Whether all known bits in this flags value are set.

pub const fn intersects(&self, other: Self) -> bool

Whether any set bits in a source flags value are also set in a target flags value.

pub const fn contains(&self, other: Self) -> bool

Whether all set bits in a source flags value are also set in a target flags value.

pub fn insert(&mut self, other: Self)

The bitwise or (|) of the bits in two flags values.

pub fn remove(&mut self, other: Self)

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. remove won’t truncate other, but the ! operator will.

pub fn toggle(&mut self, other: Self)

The bitwise exclusive-or (^) of the bits in two flags values.

pub fn set(&mut self, other: Self, value: bool)

Call insert when value is true or remove when value is false.

pub const fn intersection(self, other: Self) -> Self

The bitwise and (&) of the bits in two flags values.

pub const fn union(self, other: Self) -> Self

The bitwise or (|) of the bits in two flags values.

pub const fn difference(self, other: Self) -> Self

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

pub const fn symmetric_difference(self, other: Self) -> Self

The bitwise exclusive-or (^) of the bits in two flags values.

pub const fn complement(self) -> Self

The bitwise negation (!) of the bits in a flags value, truncating the result.

impl DbFlags

pub const fn iter(&self) -> Iter<DbFlags>

Yield a set of contained flags values.

Each yielded flags value will correspond to a defined named flag. Any unknown bits will be yielded together as a final flags value.

pub const fn iter_names(&self) -> IterNames<DbFlags>

Yield a set of contained named flags values.

This method is like iter, except only yields bits in contained named flags. Any unknown bits, or bits not corresponding to a contained flag will not be yielded.

Trait Implementations

impl Binary for DbFlags

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl BitAnd for DbFlags

fn bitand(self, other: Self) -> Self

The bitwise and (&) of the bits in two flags values.

type Output = DbFlags

The resulting type after applying the & operator.

impl BitAndAssign for DbFlags

fn bitand_assign(&mut self, other: Self)

The bitwise and (&) of the bits in two flags values.

impl BitOr for DbFlags

fn bitor(self, other: DbFlags) -> Self

The bitwise or (|) of the bits in two flags values.

type Output = DbFlags

The resulting type after applying the | operator.

impl BitOrAssign for DbFlags

fn bitor_assign(&mut self, other: Self)

The bitwise or (|) of the bits in two flags values.

impl BitXor for DbFlags

fn bitxor(self, other: Self) -> Self

The bitwise exclusive-or (^) of the bits in two flags values.

type Output = DbFlags

The resulting type after applying the ^ operator.

impl BitXorAssign for DbFlags

fn bitxor_assign(&mut self, other: Self)

The bitwise exclusive-or (^) of the bits in two flags values.

impl Clone for DbFlags

fn clone(&self) -> DbFlags

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DbFlags

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Extend<DbFlags> for DbFlags

fn extend<T: IntoIterator<Item = Self>>(&mut self, iterator: T)

The bitwise or (|) of the bits in each flags value.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Flags for DbFlags

const FLAGS: &'static [Flag<DbFlags>]

The set of defined flags.

type Bits = u32

The underlying bits type.

fn bits(&self) -> c_uint

Get the underlying bits value.

fn from_bits_retain(bits: c_uint) -> DbFlags

Convert from a bits value exactly.

fn empty() -> Self

Get a flags value with all bits unset.

fn all() -> Self

Get a flags value with all known bits set.

fn contains_unknown_bits(&self) -> bool

This method will return true if any unknown bits are set.

fn from_bits(bits: Self::Bits) -> Option<Self>

Convert from a bits value.

fn from_bits_truncate(bits: Self::Bits) -> Self

Convert from a bits value, unsetting any unknown bits.

fn from_name(name: &str) -> Option<Self>

Get a flags value with the bits of a flag with the given name set.

fn iter(&self) -> Iter<Self>

Yield a set of contained flags values.

fn iter_names(&self) -> IterNames<Self>

Yield a set of contained named flags values.

fn is_empty(&self) -> bool

Whether all bits in this flags value are unset.

fn is_all(&self) -> bool

Whether all known bits in this flags value are set.

fn intersects(&self, other: Self) -> bool

where Self: Sized,

Whether any set bits in a source flags value are also set in a target flags value.

fn contains(&self, other: Self) -> bool

where Self: Sized,

Whether all set bits in a source flags value are also set in a target flags value.

fn truncate(&mut self)

where Self: Sized,

Remove any unknown bits from the flags.

fn insert(&mut self, other: Self)

where Self: Sized,

The bitwise or (|) of the bits in two flags values.

fn remove(&mut self, other: Self)

where Self: Sized,

The intersection of a source flags value with the complement of a target flags value (&!).

fn toggle(&mut self, other: Self)

where Self: Sized,

The bitwise exclusive-or (^) of the bits in two flags values.

fn set(&mut self, other: Self, value: bool)

where Self: Sized,

Call Flags::insert when value is true or Flags::remove when value is false.

fn intersection(self, other: Self) -> Self

The bitwise and (&) of the bits in two flags values.

fn union(self, other: Self) -> Self

The bitwise or (|) of the bits in two flags values.

fn difference(self, other: Self) -> Self

The intersection of a source flags value with the complement of a target flags value (&!).

fn symmetric_difference(self, other: Self) -> Self

The bitwise exclusive-or (^) of the bits in two flags values.

fn complement(self) -> Self

The bitwise negation (!) of the bits in a flags value, truncating the result.

impl FromIterator<DbFlags> for DbFlags

fn from_iter<T: IntoIterator<Item = Self>>(iterator: T) -> Self

The bitwise or (|) of the bits in each flags value.

impl IntoIterator for DbFlags

type Item = DbFlags

The type of the elements being iterated over.

type IntoIter = Iter<DbFlags>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl LowerHex for DbFlags

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Not for DbFlags

fn not(self) -> Self

The bitwise negation (!) of the bits in a flags value, truncating the result.

type Output = DbFlags

The resulting type after applying the ! operator.

impl Octal for DbFlags

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PublicFlags for DbFlags

type Primitive = u32

The type of the underlying storage.

type Internal = InternalBitFlags

The type of the internal field on the generated flags type.

impl Sub for DbFlags

fn sub(self, other: Self) -> Self

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

type Output = DbFlags

The resulting type after applying the - operator.

impl SubAssign for DbFlags

fn sub_assign(&mut self, other: Self)

The intersection of a source flags value with the complement of a target flags value (&!).

This method is not equivalent to self & !other when other has unknown bits set. difference won’t truncate other, but the ! operator will.

impl UpperHex for DbFlags

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for DbFlags