Fix OpenHarmony's local timezone fetching and tzdata parsing

Author: ldm0

Cargo.toml

@@ -23,7 +23,7 @@ alloc = []
 libc = []
 winapi = ["windows-link"]
 std = ["alloc"]
-clock = ["winapi", "iana-time-zone", "android-tzdata", "now"]
+clock = ["winapi", "iana-time-zone", "now"]
 now = ["std"]
 oldtime = []
 wasmbind = ["wasm-bindgen", "js-sys"]
@@ -57,9 +57,6 @@ windows-bindgen = { version = "0.60" } # MSRV is 1.74
 [target.'cfg(unix)'.dependencies]
 iana-time-zone = { version = "0.1.45", optional = true, features = ["fallback"] }
 
-[target.'cfg(target_os = "android")'.dependencies]
-android-tzdata = { version = "0.1.1", optional = true }
-
 [dev-dependencies]
 serde_json = { version = "1" }
 serde_derive = { version = "1", default-features = false }

src/offset/local/mod.rs

@@ -28,6 +28,11 @@ mod inner;
 #[allow(unreachable_pub)]
 mod win_bindings;
 
+#[cfg(all(any(target_os = "android", target_env = "ohos"), feature = "clock"))]
+#[allow(dead_code)]
+#[allow(unreachable_pub)]
+pub(crate) mod tzdata;
+
 #[cfg(all(
     not(unix),
     not(windows),

src/offset/local/tz_info/timezone.rs

@@ -8,8 +8,6 @@ use std::{cmp::Ordering, fmt, str};
 use super::rule::{AlternateTime, TransitionRule};
 use super::{DAYS_PER_WEEK, Error, SECONDS_PER_DAY, parser};
 use crate::NaiveDateTime;
-#[cfg(target_env = "ohos")]
-use crate::offset::local::tz_info::parser::Cursor;
 
 /// Time zone
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -48,15 +46,21 @@ impl TimeZone {
         // attributes are not allowed on if blocks in Rust 1.38
         #[cfg(target_os = "android")]
         {
-            if let Ok(bytes) = android_tzdata::find_tz_data(tz_string) {
+            if let Ok(Some(bytes)) =
+                crate::offset::local::tzdata::find_tz_data_android_from_fs(tz_string)
+            {
                 return Self::from_tz_data(&bytes);
             }
         }
 
         // ohos merge all file into tzdata since ver35
         #[cfg(target_env = "ohos")]
         {
-            return Self::from_tz_data(&find_ohos_tz_data(tz_string)?);
+            if let Ok(Some(bytes)) =
+                crate::offset::local::tzdata::find_tz_data_ohos_from_fs(tz_string)
+            {
+                return Self::from_tz_data(&bytes);
+            }
         }
 
         let mut chars = tz_string.chars();
@@ -635,58 +639,6 @@ fn find_tz_file(path: impl AsRef<Path>) -> Result<File, Error> {
     }
 }
 
-#[cfg(target_env = "ohos")]
-fn from_tzdata_bytes(bytes: &mut Vec<u8>, tz_string: &str) -> Result<Vec<u8>, Error> {
-    const VERSION_SIZE: usize = 12;
-    const OFFSET_SIZE: usize = 4;
-    const INDEX_CHUNK_SIZE: usize = 48;
-    const ZONENAME_SIZE: usize = 40;
-
-    let mut cursor = Cursor::new(&bytes);
-    // version head
-    let _ = cursor.read_exact(VERSION_SIZE)?;
-    let index_offset_offset = cursor.read_be_u32()?;
-    let data_offset_offset = cursor.read_be_u32()?;
-    // final offset
-    let _ = cursor.read_be_u32()?;
-
-    cursor.seek_after(index_offset_offset as usize)?;
-    let mut idx = index_offset_offset;
-    while idx < data_offset_offset {
-        let index_buf = cursor.read_exact(ZONENAME_SIZE)?;
-        let offset = cursor.read_be_u32()?;
-        let length = cursor.read_be_u32()?;
-        let zone_name = str::from_utf8(index_buf)?.trim_end_matches('\0');
-        if zone_name != tz_string {
-            idx += INDEX_CHUNK_SIZE as u32;
-            continue;
-        }
-        cursor.seek_after((data_offset_offset + offset) as usize)?;
-        return match cursor.read_exact(length as usize) {
-            Ok(result) => Ok(result.to_vec()),
-            Err(_err) => Err(Error::InvalidTzFile("invalid ohos tzdata chunk")),
-        };
-    }
-
-    Err(Error::InvalidTzString("cannot find tz string within tzdata"))
-}
-
-#[cfg(target_env = "ohos")]
-fn from_tzdata_file(file: &mut File, tz_string: &str) -> Result<Vec<u8>, Error> {
-    let mut bytes = Vec::new();
-    file.read_to_end(&mut bytes)?;
-    from_tzdata_bytes(&mut bytes, tz_string)
-}
-
-#[cfg(target_env = "ohos")]
-fn find_ohos_tz_data(tz_string: &str) -> Result<Vec<u8>, Error> {
-    const TZDATA_PATH: &str = "/system/etc/zoneinfo/tzdata";
-    match File::open(TZDATA_PATH) {
-        Ok(mut file) => from_tzdata_file(&mut file, tz_string),
-        Err(err) => Err(err.into()),
-    }
-}
-
 // Possible system timezone directories
 #[cfg(unix)]
 const ZONE_INFO_DIRECTORIES: [&str; 4] =