Avoid android-tzdata and iana-time-zone dependencies.

This is achieved by disabling the clock feature on device, and a local
patch to get the timezone on host.

Bug: 326256145
Test: atest libnetsim_common_inline_tests
Change-Id: Ie6ddadc653156708fc73f2fe78dd7e1782aac828

5 files changed, 97 insertions, 20 deletions

diff --git a/Android.bp b/Android.bp
index 85d96a3..ee1d60f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,5 +1,6 @@
 // This file is generated by cargo_embargo.
-// Do not modify this file as changes will be overridden on upgrade.
+// Do not modify this file as most changes will be overridden on upgrade.
+// Content before the first "rust_*" or "genrule" module is preserved.
 
 package {
     default_applicable_licenses: ["external_rust_crates_chrono_license"],
@@ -41,17 +42,11 @@ rust_library {
     edition: "2021",
     features: [
         "alloc",
-        "android-tzdata",
-        "clock",
-        "iana-time-zone",
         "now",
         "serde",
         "std",
-        "winapi",
-        "windows-targets",
     ],
     rustlibs: [
-        "libiana_time_zone",
         "libnum_traits",
         "libserde",
     ],
@@ -62,3 +57,25 @@ rust_library {
     product_available: true,
     vendor_available: true,
 }
+
+rust_library_host {
+    name: "libchrono_clock",
+    crate_name: "chrono",
+    cargo_env_compat: true,
+    cargo_pkg_version: "0.4.34",
+    srcs: ["src/lib.rs"],
+    edition: "2021",
+    features: [
+        "alloc",
+        "clock",
+        "now",
+        "serde",
+        "std",
+        "winapi",
+        "windows-targets",
+    ],
+    rustlibs: [
+        "libnum_traits",
+        "libserde",
+    ],
+}
diff --git a/Cargo.toml b/Cargo.toml
index 9f0f82f..535a845 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -88,8 +88,6 @@ __internal_bench = []
 alloc = []
 clock = [
     "winapi",
-    "iana-time-zone",
-    "android-tzdata",
     "now",
 ]
 default = [
diff --git a/cargo_embargo.json b/cargo_embargo.json
index 64c53eb..736574c 100644
--- a/cargo_embargo.json
+++ b/cargo_embargo.json
@@ -1,12 +1,17 @@
 {
-  "apex_available": [
-    "//apex_available:platform",
-    "com.android.virt"
-  ],
-  "features": [
-    "std",
-    "clock",
-    "serde"
-  ],
-  "run_cargo": false
+  "apex_available": ["//apex_available:platform", "com.android.virt"],
+  "features": ["now", "serde", "std"],
+  "run_cargo": false,
+  "variants": [
+    {},
+    {
+      "features": ["clock", "now", "serde", "std"],
+      "module_name_overrides": { "libchrono": "libchrono_clock" },
+      "package": {
+        "chrono": {
+          "device_supported": false
+        }
+      }
+    }
+  ]
 }
diff --git a/patches/no-tzdata.patch b/patches/no-tzdata.patch
new file mode 100644
index 0000000..d4df88d
--- /dev/null
+++ b/patches/no-tzdata.patch
@@ -0,0 +1,51 @@
+diff --git a/Cargo.toml b/Cargo.toml
+index 9f0f82f..535a845 100644
+--- a/Cargo.toml
++++ b/Cargo.toml
+@@ -88,8 +88,6 @@ __internal_bench = []
+ alloc = []
+ clock = [
+     "winapi",
+-    "iana-time-zone",
+-    "android-tzdata",
+     "now",
+ ]
+ default = [
+diff --git a/patches/no-tzdata.patch b/patches/no-tzdata.patch
+index 230cf9e..e69de29 100644
+--- a/patches/no-tzdata.patch
++++ b/patches/no-tzdata.patch
+@@ -1,13 +0,0 @@
+-diff --git a/Cargo.toml b/Cargo.toml
+-index 9f0f82f..535a845 100644
+---- a/Cargo.toml
+-+++ b/Cargo.toml
+-@@ -88,8 +88,6 @@ __internal_bench = []
+- alloc = []
+- clock = [
+-     "winapi",
+--    "iana-time-zone",
+--    "android-tzdata",
+-     "now",
+- ]
+- default = [
+diff --git a/src/offset/local/unix.rs b/src/offset/local/unix.rs
+index ce96a6e..ce844cc 100644
+--- a/src/offset/local/unix.rs
++++ b/src/offset/local/unix.rs
+@@ -77,8 +77,14 @@ const TZDB_LOCATION: &str = "/usr/share/lib/zoneinfo";
+ #[cfg(not(any(target_os = "android", target_os = "aix")))]
+ const TZDB_LOCATION: &str = "/usr/share/zoneinfo";
+ 
++// Android patch to avoid iana-time-zone dependency.
++fn get_timezone() -> Result<String, std::io::Error> {
++    let tz_name = std::fs::read_to_string("/etc/timezone")?;
++    Ok(tz_name.trim_end().to_string())
++}
++
+ fn fallback_timezone() -> Option<TimeZone> {
+-    let tz_name = iana_time_zone::get_timezone().ok()?;
++    let tz_name = get_timezone().ok()?;
+     #[cfg(not(target_os = "android"))]
+     let bytes = fs::read(format!("{}/{}", TZDB_LOCATION, tz_name)).ok()?;
+     #[cfg(target_os = "android")]
diff --git a/src/offset/local/unix.rs b/src/offset/local/unix.rs
index ce96a6e..ce844cc 100644
--- a/src/offset/local/unix.rs
+++ b/src/offset/local/unix.rs
@@ -77,8 +77,14 @@ const TZDB_LOCATION: &str = "/usr/share/lib/zoneinfo";
 #[cfg(not(any(target_os = "android", target_os = "aix")))]
 const TZDB_LOCATION: &str = "/usr/share/zoneinfo";
 
+// Android patch to avoid iana-time-zone dependency.
+fn get_timezone() -> Result<String, std::io::Error> {
+    let tz_name = std::fs::read_to_string("/etc/timezone")?;
+    Ok(tz_name.trim_end().to_string())
+}
+
 fn fallback_timezone() -> Option<TimeZone> {
-    let tz_name = iana_time_zone::get_timezone().ok()?;
+    let tz_name = get_timezone().ok()?;
     #[cfg(not(target_os = "android"))]
     let bytes = fs::read(format!("{}/{}", TZDB_LOCATION, tz_name)).ok()?;
     #[cfg(target_os = "android")]