#[non_exhaustive]
pub enum DiskImageFormat {
Raw,
Vhd,
Vmdk,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against DiskImageFormat, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let diskimageformat = unimplemented!();
match diskimageformat {
DiskImageFormat::Raw => { /* ... */ },
DiskImageFormat::Vhd => { /* ... */ },
DiskImageFormat::Vmdk => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when diskimageformat represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant DiskImageFormat::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
DiskImageFormat::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str on it yields "NewFeature".
This match expression is forward-compatible when executed with a newer
version of SDK where the variant DiskImageFormat::NewFeature is defined.
Specifically, when diskimageformat represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on DiskImageFormat::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
Raw
Vhd
Vmdk
Unknown(UnknownVariantValue)
Unknown contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for DiskImageFormat
impl AsRef<str> for DiskImageFormat
source§impl Clone for DiskImageFormat
impl Clone for DiskImageFormat
source§fn clone(&self) -> DiskImageFormat
fn clone(&self) -> DiskImageFormat
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for DiskImageFormat
impl Debug for DiskImageFormat
source§impl From<&str> for DiskImageFormat
impl From<&str> for DiskImageFormat
source§impl FromStr for DiskImageFormat
impl FromStr for DiskImageFormat
source§impl Hash for DiskImageFormat
impl Hash for DiskImageFormat
source§impl Ord for DiskImageFormat
impl Ord for DiskImageFormat
source§fn cmp(&self, other: &DiskImageFormat) -> Ordering
fn cmp(&self, other: &DiskImageFormat) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq<DiskImageFormat> for DiskImageFormat
impl PartialEq<DiskImageFormat> for DiskImageFormat
source§fn eq(&self, other: &DiskImageFormat) -> bool
fn eq(&self, other: &DiskImageFormat) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd<DiskImageFormat> for DiskImageFormat
impl PartialOrd<DiskImageFormat> for DiskImageFormat
source§fn partial_cmp(&self, other: &DiskImageFormat) -> Option<Ordering>
fn partial_cmp(&self, other: &DiskImageFormat) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read moreimpl Eq for DiskImageFormat
impl StructuralEq for DiskImageFormat
impl StructuralPartialEq for DiskImageFormat
Auto Trait Implementations§
impl RefUnwindSafe for DiskImageFormat
impl Send for DiskImageFormat
impl Sync for DiskImageFormat
impl Unpin for DiskImageFormat
impl UnwindSafe for DiskImageFormat
Blanket Implementations§
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.