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Diffstat (limited to 'src/rust/smartlist/smartlist.rs')
-rw-r--r-- | src/rust/smartlist/smartlist.rs | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/src/rust/smartlist/smartlist.rs b/src/rust/smartlist/smartlist.rs deleted file mode 100644 index d8f8083dff..0000000000 --- a/src/rust/smartlist/smartlist.rs +++ /dev/null @@ -1,115 +0,0 @@ -// Copyright (c) 2016-2019, The Tor Project, Inc. */ -// See LICENSE for licensing information */ - -use libc::{c_char, c_int}; -use std::ffi::CStr; -use std::slice; - -/// Smartlists are a type used in C code in tor to define a collection of a -/// generic type, which has a capacity and a number used. Each Smartlist -/// defines how to extract the list of values from the underlying C structure -/// -/// Implementations are required to have a C representation, as this module -/// serves purely to translate smartlists as defined in tor to vectors in Rust. -pub trait Smartlist<T> { - fn get_list(&self) -> Vec<T>; -} - -#[repr(C)] -pub struct Stringlist { - pub list: *const *const c_char, - pub num_used: c_int, - pub capacity: c_int, -} - -impl Smartlist<String> for Stringlist { - fn get_list(&self) -> Vec<String> { - let empty: Vec<String> = Vec::new(); - let mut rust_list: Vec<String> = Vec::new(); - - if self.list.is_null() || self.num_used == 0 { - return empty; - } - - // unsafe, as we need to extract the smartlist list into a vector of - // pointers, and then transform each element into a Rust string. - let elems: &[*const c_char] = - unsafe { slice::from_raw_parts(self.list, self.num_used as usize) }; - - for elem in elems.iter() { - if elem.is_null() { - continue; - } - - // unsafe, as we need to create a cstring from the referenced - // element - let c_string = unsafe { CStr::from_ptr(*elem) }; - - let r_string = match c_string.to_str() { - Ok(n) => n, - Err(_) => return empty, - }; - - rust_list.push(String::from(r_string)); - } - - rust_list - } -} - -// TODO: CHK: this module maybe should be tested from a test in C with a -// smartlist as defined in tor. -#[cfg(test)] -mod test { - #[test] - fn test_get_list_of_strings() { - extern crate libc; - - use libc::c_char; - use std::ffi::CString; - - use super::Smartlist; - use super::Stringlist; - - { - // test to verify that null pointers are gracefully handled - use std::ptr; - - let sl = Stringlist { - list: ptr::null(), - num_used: 0, - capacity: 0, - }; - - let data = sl.get_list(); - assert_eq!(0, data.len()); - } - - { - let args = vec![String::from("a"), String::from("b")]; - - // for each string, transform it into a CString - let c_strings: Vec<_> = args - .iter() - .map(|arg| CString::new(arg.as_str()).unwrap()) - .collect(); - - // then, collect a pointer for each CString - let p_args: Vec<_> = c_strings.iter().map(|arg| arg.as_ptr()).collect(); - - let p: *const *const c_char = p_args.as_ptr(); - - // This is the representation that we expect when receiving a - // smartlist at the Rust/C FFI layer. - let sl = Stringlist { - list: p, - num_used: 2, - capacity: 2, - }; - - let data = sl.get_list(); - assert_eq!("a", &data[0]); - assert_eq!("b", &data[1]); - } - } -} |