RUST-1952 Use std::ffi::c_char instead of *const i8 (#30)

Author: abr-egn

mongocrypt/src/convert.rs

@@ -1,9 +1,11 @@
+use std::ffi::CString;
+
 use bson::{Document, RawDocument};
 use mongocrypt_sys as sys;
 
 use crate::{
     binary::BinaryBuf,
-    error::{self, Result},
+    error::{self, encoding, Result},
 };
 
 pub(crate) fn doc_binary(doc: &Document) -> Result<BinaryBuf> {
@@ -13,15 +15,20 @@ pub(crate) fn doc_binary(doc: &Document) -> Result<BinaryBuf> {
     Ok(BinaryBuf::new(bytes))
 }
 
+pub(crate) fn path_cstring(path: &std::path::Path) -> Result<CString> {
+    let bytes = path_bytes(path)?;
+    CString::new(bytes).map_err(|e| encoding!("could not convert path to cstring: {:?}", e))
+}
+
 #[cfg(unix)]
-pub(crate) fn path_bytes(path: &std::path::Path) -> Result<Vec<u8>> {
+fn path_bytes(path: &std::path::Path) -> Result<Vec<u8>> {
     use std::os::unix::prelude::OsStrExt;
 
     Ok(path.as_os_str().as_bytes().to_vec())
 }
 
 #[cfg(not(unix))]
-pub(crate) fn path_bytes(path: &std::path::Path) -> Result<Vec<u8>> {
+fn path_bytes(path: &std::path::Path) -> Result<Vec<u8>> {
     // This is correct for Windows because libmongocrypt internally converts
     // from utf8 to utf16 on that platform.
     use error::Error;
@@ -32,9 +39,9 @@ pub(crate) fn path_bytes(path: &std::path::Path) -> Result<Vec<u8>> {
     Ok(s.as_bytes().to_vec())
 }
 
-pub(crate) fn str_bytes_len(s: &str) -> Result<(*const i8, i32)> {
+pub(crate) fn str_bytes_len(s: &str) -> Result<(*const std::ffi::c_char, i32)> {
     Ok((
-        s.as_bytes().as_ptr() as *const i8,
+        s.as_bytes().as_ptr() as *const std::ffi::c_char,
         s.as_bytes().len().try_into()?,
     ))
 }

mongocrypt/src/hooks.rs

@@ -360,7 +360,8 @@ fn write_status(result: Result<()>, c_status: *mut sys::mongocrypt_status_t) ->
                 c_status,
                 sys::mongocrypt_status_type_t_MONGOCRYPT_STATUS_ERROR_CLIENT,
                 0,
-                b"Failed to record error, see logs for details\0".as_ptr() as *const i8,
+                b"Failed to record error, see logs for details\0".as_ptr()
+                    as *const std::ffi::c_char,
                 -1,
             );
         }

mongocrypt/src/lib.rs

@@ -3,7 +3,7 @@ use std::{borrow::Borrow, ffi::CStr, path::Path, ptr, sync::Mutex};
 use bson::Document;
 #[cfg(test)]
 use convert::str_bytes_len;
-use convert::{doc_binary, path_bytes};
+use convert::{doc_binary, path_cstring};
 use ctx::CtxBuilder;
 use mongocrypt_sys as sys;
 
@@ -155,12 +155,11 @@ impl CryptBuilder {
     /// `set_crypt_shared_lib_path_override`, then paths
     /// appended here will have no effect.
     pub fn append_crypt_shared_lib_search_path(self, path: &Path) -> Result<Self> {
-        let mut tmp = path_bytes(path)?;
-        tmp.push(0);
+        let tmp = path_cstring(path)?;
         unsafe {
             sys::mongocrypt_setopt_append_crypt_shared_lib_search_path(
                 *self.inner.borrow(),
-                tmp.as_ptr() as *const i8,
+                tmp.as_ptr(),
             );
         }
         Ok(self)
@@ -184,12 +183,11 @@ impl CryptBuilder {
     /// initialize a valid crypt_shared library instance for the path specified, then
     /// the initialization will fail with an error.
     pub fn set_crypt_shared_lib_path_override(self, path: &Path) -> Result<Self> {
-        let mut tmp = path_bytes(path)?;
-        tmp.push(0);
+        let tmp = path_cstring(path)?;
         unsafe {
             sys::mongocrypt_setopt_set_crypt_shared_lib_path_override(
                 *self.inner.borrow(),
-                tmp.as_ptr() as *const i8,
+                tmp.as_ptr(),
             );
         }
         Ok(self)