Struct ProtectedStrVec 

pub struct ProtectedStrVec {
    inner: StrVec,
    len: isize,
    _protect: Option<OwnedProtect>,
}

GC-protected view over an R character vector (STRSXP).

Unlike StrVec (which is Copy and trusts the caller for GC protection), ProtectedStrVec owns an OwnedProtect guard that keeps the STRSXP alive. All borrowed data (&str, iterators) has its lifetime tied to &self, not 'static — preventing use-after-GC bugs at compile time.

When to use

• StrVec: for SEXP arguments to .Call (R protects them), or when you manage protection yourself. Lightweight, Copy.
• ProtectedStrVec: when you allocate or receive an STRSXP and need to keep it alive beyond the immediate scope. Not Copy.

Example

#[miniextendr]
pub fn count_unique(strings: ProtectedStrVec) -> i32 {
    let unique: HashSet<&str> = strings.iter()
        .filter_map(|s| s)
        .collect();
    unique.len() as i32
}

Fields

inner: StrVec

len: isize

_protect: Option<OwnedProtect>

Implementations

impl ProtectedStrVec

pub unsafe fn new(sexp: SEXP) -> Self

Create a protected view over an STRSXP.

Calls Rf_protect on the SEXP. Use from_sexp_trusted when the SEXP is already protected (e.g., .Call arguments) to avoid double-protecting.

Safety

• sexp must be a valid STRSXP.
• Must be called from the R main thread.

pub unsafe fn from_sexp_trusted(sexp: SEXP) -> Self

Create a view without adding GC protection.

Use this when the SEXP is already protected by R (e.g., a .Call argument, or in a ProtectScope). Avoids the redundant Rf_protect/Rf_unprotect pair.

The lifetime-bound &str borrows are still enforced — this only skips the protect stack push, not the safety guarantees.

Safety

• sexp must be a valid STRSXP.
• sexp must remain GC-protected for the lifetime of this struct.
• Must be called from the R main thread.

pub fn len(&self) -> isize

Number of elements.

pub fn is_empty(&self) -> bool

Whether the vector is empty.

pub fn get_str(&self, idx: isize) -> Option<&str>

Get the string at index (zero-copy, lifetime tied to &self).

Returns None for out-of-bounds or NA_character_.

pub fn get_cow(&self, idx: isize) -> Option<Cow<'_, str>>

Get the string at index as Cow<str> (encoding-safe, lifetime tied to &self).

pub fn iter(&self) -> ProtectedStrVecIter<'_>

Iterate over elements as Option<&str> (lifetime tied to &self).

pub fn iter_cow(&self) -> ProtectedStrVecCowIter<'_>

Iterate over elements as Option<Cow<str>> (encoding-safe).

pub fn as_sexp(&self) -> SEXP

Get the underlying SEXP (still protected by this handle).

pub fn as_strvec(&self) -> StrVec

Get the inner StrVec (unprotected copy — caller assumes protection responsibility).

Trait Implementations

impl Debug for ProtectedStrVec

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

Formats the value using the given formatter.

impl<'a> IntoIterator for &'a ProtectedStrVec

type Item = Option<&'a str>

The type of the elements being iterated over.

type IntoIter = ProtectedStrVecIter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl IntoR for ProtectedStrVec

type Error = Infallible

The error type for fallible conversions.

fn try_into_sexp(self) -> Result<SEXP, Self::Error>

Try to convert this value to an R SEXP.

unsafe fn try_into_sexp_unchecked(self) -> Result<SEXP, Self::Error>

Try to convert to SEXP without thread safety checks.

fn into_sexp(self) -> SEXP

Convert this value to an R SEXP, panicking on error.

unsafe fn into_sexp_unchecked(self) -> SEXP

where Self: Sized,

Convert to SEXP without thread safety checks, panicking on error.

impl TryFromSexp for ProtectedStrVec

type Error = SexpError

The error type returned when conversion fails.

fn try_from_sexp(sexp: SEXP) -> Result<Self, Self::Error>

Attempt to convert an R SEXP to this Rust type.

unsafe fn try_from_sexp_unchecked(sexp: SEXP) -> Result<Self, Self::Error>

Convert from SEXP without thread safety checks.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes