Add env_preferences crate (#5081)

Cargo.toml

@@ -71,6 +71,7 @@ members = [
     "utils/pattern",
     "utils/preferences",
     "utils/resb",
+    "utils/env_preferences",
     "utils/tinystr",
     "utils/tzif",
     "utils/writeable",

utils/env_preferences/Cargo.toml

@@ -0,0 +1,35 @@
+# This file is part of ICU4X. For terms of use, please see the file
+# called LICENSE at the top level of the ICU4X source tree
+# (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+[package]
+name = "env_preferences"
+version.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+edition.workspace = true
+repository.workspace = true
+homepage.workspace = true
+license.workspace = true
+categories.workspace = true
+include.workspace = true
+
+[dependencies]
+core-foundation-sys = "0.8.6"
+libc = "0.2.155"
+
+[dependencies.windows]
+version = "0.56.0"
+features = [
+    "System",
+    "Foundation",
+    "System_UserProfile",
+    "Foundation_Collections",
+    "Globalization",
+    "Globalization_DateTimeFormatting",
+    "Win32",
+    "Win32_Globalization"
+]
+
+[dev-dependencies]
+icu_locale = { path = "../../components/locale" }

utils/env_preferences/LICENSE

@@ -0,0 +1,46 @@
+UNICODE LICENSE V3
+
+COPYRIGHT AND PERMISSION NOTICE
+
+Copyright © 2020-2024 Unicode, Inc.
+
+NOTICE TO USER: Carefully read the following legal agreement. BY
+DOWNLOADING, INSTALLING, COPYING OR OTHERWISE USING DATA FILES, AND/OR
+SOFTWARE, YOU UNEQUIVOCALLY ACCEPT, AND AGREE TO BE BOUND BY, ALL OF THE
+TERMS AND CONDITIONS OF THIS AGREEMENT. IF YOU DO NOT AGREE, DO NOT
+DOWNLOAD, INSTALL, COPY, DISTRIBUTE OR USE THE DATA FILES OR SOFTWARE.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of data files and any associated documentation (the "Data Files") or
+software and any associated documentation (the "Software") to deal in the
+Data Files or Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, and/or sell
+copies of the Data Files or Software, and to permit persons to whom the
+Data Files or Software are furnished to do so, provided that either (a)
+this copyright and permission notice appear with all copies of the Data
+Files or Software, or (b) this copyright and permission notice appear in
+associated Documentation.
+
+THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+THIRD PARTY RIGHTS.
+
+IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
+BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE DATA
+FILES OR SOFTWARE.
+
+Except as contained in this notice, the name of a copyright holder shall
+not be used in advertising or otherwise to promote the sale, use or other
+dealings in these Data Files or Software without prior written
+authorization of the copyright holder.
+
+SPDX-License-Identifier: Unicode-3.0
+
+—
+
+Portions of ICU4X may have been adapted from ICU4C and/or ICU4J.
+ICU 1.8.1 to ICU 57.1 © 1995-2016 International Business Machines Corporation and others.

utils/env_preferences/src/apple.rs

@@ -0,0 +1,164 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use core_foundation_sys::{
+    array::{CFArrayGetCount, CFArrayGetValueAtIndex},
+    base::{CFIndex, CFRelease, CFRetain},
+    calendar::{CFCalendarCopyCurrent, CFCalendarCopyLocale, CFCalendarGetIdentifier},
+    locale::{CFLocaleCopyPreferredLanguages, CFLocaleGetIdentifier},
+    string::{
+        kCFStringEncodingUTF8, CFStringGetCString, CFStringGetCStringPtr, CFStringGetLength,
+        CFStringRef,
+    },
+    timezone,
+};
+use libc::c_char;
+use std::ffi::{CStr, CString};
+
+use crate::RetrievalError;
+
+/// Helps to get string, it tries to get the string directly from the pointer itself, in case it is unable to retrieve
+/// the string (c_str_ptr is NULL) a buffer is created of size `length + 1` and we perform manual allocations to get
+/// the string
+fn get_string(ptr: CFStringRef) -> Result<String, RetrievalError> {
+    // SAFETY: The call to `CFStringGetCStringPtr` because the reference of string we are accessing is not `NULL`
+    // Returns pointer in O(1) without any memory allocation. This can return NULL so we are handling it by directly
+    // copying it using `CFStringGetCString`
+    let c_str_ptr: *const c_char = unsafe { CFStringGetCStringPtr(ptr, kCFStringEncodingUTF8) };
+
+    if !c_str_ptr.is_null() {
+        // SAFETY: A valid `NULL` terminator is present which is a requirement of `from_ptr`
+        let lang_rust_str = unsafe { CStr::from_ptr(c_str_ptr) }.to_str()?;
+        Ok(lang_rust_str.to_string())
+    } else {
+        // `c_str_ptr` is null, i.e. `CFStringGetCStringPtr` couldn't give desired output, trying with
+        // manual allocations
+        // SAFETY: It returns length of the string, from above conditional statement we ensure
+        // that the `lang_ptr` is not NULL thus making it safe to call
+        let length = unsafe { CFStringGetLength(ptr) as usize };
+
+        let mut c_str_buf: Vec<u8> = vec![0; length + 1];
+
+        // SAFETY: Safety is ensured by following points
+        // 1. `lang_ptr` is not NULL, checked through conditional statement
+        // 2. `c_str_buf` is large enough and in scope after this call
+        unsafe {
+            CFStringGetCString(
+                ptr,
+                c_str_buf.as_mut_ptr() as *mut c_char,
+                c_str_buf.len() as CFIndex,
+                kCFStringEncodingUTF8,
+            );
+        }
+
+        let c_string = CString::from_vec_with_nul(c_str_buf)?;
+        c_string
+            .into_string()
+            .map_err(|e| RetrievalError::ConversionError(e.utf8_error()))
+    }
+}
+
+pub fn get_locales() -> Result<Vec<String>, RetrievalError> {
+    let mut languages: Vec<String> = Vec::new();
+
+    // SAFETY: The call to `CFLocaleCopyPreferredLanguages` returns an immutable reference to `CFArray` which is owned by us
+    // https://developer.apple.com/documentation/corefoundation/cfarrayref. It is ensured that `locale_carr_ref` is not mutated
+    // Immutablility ensures that nothing is overriden during it's scope
+    let locale_carr_ref = unsafe { CFLocaleCopyPreferredLanguages() };
+
+    if !locale_carr_ref.is_null() {
+        // SAFETY: The call to `CFArrayGetCount` is only made when is `locale_carr_ref` is not `NULL`
+        let count = unsafe { CFArrayGetCount(locale_carr_ref as _) };
+
+        for i in 0..count {
+            // SAFETY: The call to `CFArrayGetValueAtIndex` is safe because we are iterating from 0 to count (`CFArrayGetCount`) which
+            // in itself will always be greater than 0 and less than count ensuring we will not get "out of bounds" error
+            let lang_ptr = unsafe { CFArrayGetValueAtIndex(locale_carr_ref, i) };
+
+            if !lang_ptr.is_null() {
+                let locale_str = get_string(lang_ptr as CFStringRef)?;
+                languages.push(locale_str);
+            } else {
+                return Err(RetrievalError::NullLocale);
+            }
+        }
+    } else {
+        // No need to release memory for `locale_carr_ref` since it is NULL
+        return Err(RetrievalError::NullLocale);
+    }
+    // Release for memory
+    unsafe {
+        CFRelease(locale_carr_ref as _);
+    }
+
+    Ok(languages)
+}
+
+pub fn get_system_calendars() -> Result<Vec<(String, String)>, RetrievalError> {
+    let mut calendars = Vec::new();
+    let calendar_locale_str: String;
+    let mut calendar_identifier_str = String::new();
+
+    // SAFETY: The call to `CFCalendarCopyCurrent` returns a calendar object owned by us
+    // This calendar object is used extract locale and type of calendar (identifier)
+    let calendar = unsafe { CFCalendarCopyCurrent() };
+
+    if !calendar.is_null() {
+        // SAFETY: Retaining the calendar object when not `NULL`
+        // It is released when all actions are completed
+        unsafe { CFRetain(calendar as _) };
+
+        // SAFETY: Retrieves `CFLocale` object for the calendar, the `if` statement ensures we don't
+        // pass in a `NULL` references
+        let locale = unsafe { CFCalendarCopyLocale(calendar as _) };
+
+        // SAFETY: Retrieves `CFString` (identifier) for the calendar, the `if` statement ensures
+        // we don't pass in a `NULL` references
+        let identifier = unsafe { CFCalendarGetIdentifier(calendar as _) };
+
+        if !locale.is_null() {
+            // SAFETY: Retain the locale object, released when we extracted the string
+            unsafe { CFRetain(locale as _) };
+
+            // SAFETY: Retrieves `CFString` (identifier) for the calendar, the `if` statement ensures
+            // we don't pass in a `NULL` reference
+            let locale_identifier = unsafe { CFLocaleGetIdentifier(locale) };
+            calendar_locale_str = get_string(locale_identifier as CFStringRef)?;
+
+            // SAFETY: Releases the locale object which was retained
+            unsafe { CFRelease(locale as _) };
+        } else {
+            return Err(RetrievalError::NullLocale);
+        }
+
+        if !identifier.is_null() {
+            calendar_identifier_str = get_string(identifier as CFStringRef)?;
+        }
+        // SAFETY: Release the calendar when done to avoid memory leaks
+        unsafe { CFRelease(calendar as _) };
+
+        calendars.push((calendar_locale_str, calendar_identifier_str));
+    } else {
+        return Err(RetrievalError::NullCalendar);
+    }
+
+    Ok(calendars)
+}
+
+pub fn get_system_timezone() -> Result<String, RetrievalError> {
+    // SAFETY: Returns the time zone currently used by the system
+    // Returns an immutable reference to TimeZone object owned by us
+    let timezone = unsafe { timezone::CFTimeZoneCopySystem() };
+
+    if !timezone.is_null() {
+        // SAFETY: Extracts name of time zone from the TimeZone object, reference to timezone
+        // is guaranteed to be not NULL
+        let cf_string = unsafe { timezone::CFTimeZoneGetName(timezone) };
+
+        if !cf_string.is_null() {
+            return Ok(get_string(cf_string)?);
+        }
+    }
+    Err(RetrievalError::NullTimeZone)
+}