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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::path::Path;
use std::ffi;
use {
rust_icu_common as common, rust_icu_sys as sys, rust_icu_sys::versioned_function,
std::convert::TryFrom, std::os::raw,
};
/// Variants of [UDataMemory].
#[derive(Debug)]
enum Rep {
/// The data memory is backed by a user-supplied buffer.
Buffer(Vec<u8>),
/// The data memory is backed by a resource file.
Resource(
// This would have been std::ptr::NonNull if we didn't have to
// implement Send and Sync.
// We only ever touch this pointer in Rust when we initialize
// Rep::Resource, and when we dealocate Rep::Resource.
*const sys::UDataMemory,
),
}
// Safety: The *const sys::UDataMemory above is only used by the underlying C++
// library.
unsafe impl Send for Rep {}
unsafe impl Sync for Rep {}
/// Sets the directory from which to load ICU data resources.
///
/// Implements `u_setDataDirectory`.
pub fn set_data_directory(dir: &Path) {
let dir_cstr = ffi::CString::new
(dir.to_str().expect("this should never be a runtime error"))
.expect("this should never be a runtim error");
unsafe {
versioned_function!(u_setDataDirectory)(dir_cstr.as_ptr())
};
}
/// The type of the ICU resource requested. Some standard resources have their
/// canned types. In case you run into one that is not captured here, use `Custom`,
/// and consider sending a pull request to add the new resource type.
pub enum Type {
/// An empty resource type. This is ostensibly allowed, but unclear when
/// it is applicable.
Empty,
/// The unpacked resource type, equivalent to "res" in ICU4C.
Res,
/// The cnv resource type, equivalent to "cnv" in ICU4C.
Cnv,
/// The "common" data type, equivalent to "dat" in ICU4C.
Dat,
/// A custom data type, in case none of the above fit your use case. It
/// is not clear whether this would ever be useful, but the ICU4C API
/// allows for it, so we must too.
Custom(String),
}
impl AsRef<str> for Type {
fn as_ref(&self) -> &str {
match self {
Type::Empty => &"",
Type::Res => &"res",
Type::Dat => &"dat",
Type::Cnv => &"cnv",
Type::Custom(ref s) => &s,
}
}
}
/// Implements `UDataMemory`.
///
/// Represents data memory backed by a borrowed memory buffer used for loading ICU data.
/// [UDataMemory] is very much not thread safe, as it affects the global state of the ICU library.
/// This suggests that the best way to use this data is to load it up in a main thread, or access
/// it through a synchronized wrapper.
#[derive(Debug)]
pub struct UDataMemory {
// The internal representation of [UDataMemory].
// May vary, depending on the way the struct is created.
//
// See: [UDataMemory::try_from] and [UDataMemory::open].
rep: Rep,
}
impl Drop for UDataMemory {
// Implements `u_cleanup`.
fn drop(&mut self) {
if let Rep::Resource(r) = self.rep {
unsafe {
// Safety: there is no other way to close the memory that the
// underlying C++ library uses but to pass it into this function.
versioned_function!(udata_close)(r as *mut sys::UDataMemory)
};
}
// Without this, resource references will remain, but memory will be gone.
unsafe {
// Safety: no other way to call this function.
versioned_function!(u_cleanup)()
};
}
}
impl TryFrom<Vec<u8>> for crate::UDataMemory {
type Error = common::Error;
/// Makes a UDataMemory out of a buffer.
///
/// Implements `udata_setCommonData`.
fn try_from(buf: Vec<u8>) -> Result<Self, Self::Error> {
let mut status = sys::UErrorCode::U_ZERO_ERROR;
// Expects that buf is a valid pointer and that it contains valid
// ICU data. If data is invalid, an error status will be set.
// No guarantees for invalid pointers.
unsafe {
versioned_function!(udata_setCommonData)(
buf.as_ptr() as *const raw::c_void,
&mut status,
);
};
common::Error::ok_or_warning(status)?;
Ok(UDataMemory { rep: Rep::Buffer(buf) })
}
}
impl crate::UDataMemory {
/// Uses the resources from the supplied resource file.
///
/// This may end up being more efficient compared to loading from a buffer,
/// as ostensibly the resources would be memory mapped to only the needed
/// parts.
///
/// - The `path` is the file path at which to find the resource file. Ostensibly
/// specifying `None` here will load from the "default" ICU_DATA path.
/// I have not been able to confirm this.
///
/// - The `a_type` is the type of the resource file. It is not clear whether
/// the resource file type is a closed or open set, so we provide for both
/// possibilities.
///
/// - The `name` is the name of the resource file. It is documented nullable
/// in the ICU documentation. Pass `None` here to pass nullptr to the
/// underlying C API.
///
/// Presumably using `UDataMemory::open(Some("/dir/too"), Type::Res, Some("filename")` would
/// attempt to load ICU data from `/dir/too/filename.res`, as well as some other
/// canonical permutations of the above. The full documentation is
/// [here][1], although I could not confirm that the documentation is actually
/// describing what the code does. Also, using `None` at appropriate places
/// seems to be intended to load data from [some "default" sites][2]. I have
/// however observed that the actual behavior diverges from that documentation.
///
/// Implements `udata_open`.
///
/// [1]: https://unicode-org.github.io/icu/userguide/icu_data/#how-data-loading-works
/// [2]: https://unicode-org.github.io/icu/userguide/icu_data/#icu-data-directory
pub fn open(path: Option<&Path>, a_type: Type, name: Option<&str>) -> Result<Self, common::Error> {
let mut status = sys::UErrorCode::U_ZERO_ERROR;
let path_cstr = path.map(|s| { ffi::CString::new(s.to_str().expect("should never be a runtime error")).unwrap()});
let name_cstr = name.map(|s| { ffi::CString::new(s).expect("should never be a runtime error") } );
let type_cstr = ffi::CString::new(a_type.as_ref()).expect("should never be a runtime errror");
let rep = Self::get_resource(
path_cstr.as_ref().map(|s| s.as_c_str()),
type_cstr.as_c_str(),
name_cstr.as_ref().map(|s| s.as_c_str()),
&mut status);
common::Error::ok_or_warning(status)?;
// Make sure that all CStrs outlive the call to Self::get_resource. It is
// all too easy to omit `path_cstr.as_ref()` above, resulting in *_cstr
// being destroyed before a call to Self::get_resource happens. Fun.
let (_a, _b, _c) = (path_cstr, name_cstr, type_cstr);
Ok(crate::UDataMemory{ rep })
}
fn get_resource(path: Option<&ffi::CStr>, a_type: &ffi::CStr, name: Option<&ffi::CStr>, status: &mut sys::UErrorCode) -> Rep {
unsafe {
// Safety: we do what we must to call the underlying unsafe C API, and only return an
// opaque enum, to ensure that no rust client code may touch the raw pointer.
assert!(common::Error::is_ok(*status));
// Would be nicer if there were examples of udata_open usage to
// verify this.
let rep: *const sys::UDataMemory = versioned_function!(udata_open)(
path.map(|s| s.as_ptr()).unwrap_or(std::ptr::null()),
a_type.as_ptr(),
name.map(|c| c.as_ptr()).unwrap_or(std::ptr::null()),
status);
// Sadly we can not use NonNull, as we can not make the resulting
// type Sync or Send.
assert!(!rep.is_null());
Rep::Resource(rep)
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::sync::{Mutex, Weak, Arc};
use std::thread;
// We don't use UDataMemory in threaded contexts, but our users do. So let's
// ensure we can do this.
#[test]
fn send_sync_impl() {
let memory: Arc<Mutex<Weak<UDataMemory>>>= Arc::new(Mutex::new(Weak::new()));
// Ensure Sync.
let _clone = memory.clone();
thread::spawn(move || {
// Ensure Send.
let _m = memory;
});
}
#[test]
fn send_impl() {
let memory: Weak<UDataMemory> = Weak::new();
let _clone = memory.clone();
thread::spawn(move || {
let _m = memory;
});
}
}