Struct mz_pgwire_common::codec::Cursor

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pub struct Cursor<'a> {
    buf: &'a [u8],
}
Expand description

Decodes data within pgwire messages.

The API provided is very similar to bytes::Buf, but operations return errors rather than panicking. This is important for safety, as we don’t want to crash if the user sends us malformed pgwire messages.

There are also some special-purpose methods, like Cursor::read_cstr, that are specific to pgwire messages.

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§buf: &'a [u8]

Implementations§

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impl<'a> Cursor<'a>

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pub fn new(buf: &'a [u8]) -> Cursor<'_>

Constructs a new Cursor from a byte slice. The cursor will begin decoding from the beginning of the slice.

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pub fn peek_byte(&self) -> Result<u8, Error>

Returns the next byte without advancing the cursor.

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pub fn read_byte(&mut self) -> Result<u8, Error>

Returns the next byte, advancing the cursor by one byte.

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pub fn read_cstr(&mut self) -> Result<&'a str, Error>

Returns the next null-terminated string. The null character is not included the returned string. The cursor is advanced past the null- terminated string.

If there is no null byte remaining in the string, returns CodecError::StringNoTerminator. If the string is not valid UTF-8, returns an io::Error with an error kind of io::ErrorKind::InvalidInput.

NOTE(benesch): it is possible that returning a string here is wrong, and we should be returning bytes, so that we can support messages that are not UTF-8 encoded. At the moment, we’ve not discovered a need for this, though, and using proper strings is convenient.

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pub fn read_i16(&mut self) -> Result<i16, Error>

Reads the next 16-bit signed integer, advancing the cursor by two bytes.

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pub fn read_i32(&mut self) -> Result<i32, Error>

Reads the next 32-bit signed integer, advancing the cursor by four bytes.

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pub fn read_u32(&mut self) -> Result<u32, Error>

Reads the next 32-bit unsigned integer, advancing the cursor by four bytes.

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pub fn read_format(&mut self) -> Result<Format, Error>

Reads the next 16-bit format code, advancing the cursor by two bytes.

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pub fn advance(&mut self, n: usize)

Advances the cursor by n bytes.

Trait Implementations§

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impl<'a> Debug for Cursor<'a>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a> Freeze for Cursor<'a>

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impl<'a> RefUnwindSafe for Cursor<'a>

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impl<'a> Send for Cursor<'a>

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impl<'a> Sync for Cursor<'a>

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impl<'a> Unpin for Cursor<'a>

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impl<'a> UnwindSafe for Cursor<'a>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, U> CastInto<U> for T
where U: CastFrom<T>,

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fn cast_into(self) -> U

Performs the cast.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FutureExt for T

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fn with_context(self, otel_cx: Context) -> WithContext<Self>

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
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fn with_current_context(self) -> WithContext<Self>

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoRequest<T> for T

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fn into_request(self) -> Request<T>

Wrap the input message T in a tonic::Request
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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type Error = Infallible

The type returned in the event of a conversion error.
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Performs the conversion.
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where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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where V: MultiLane<T>,

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fn vzip(self) -> V

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where S: Into<Dispatch>,

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