Improve system time zone detection

Cargo.lock

@@ -17,6 +17,7 @@ dependencies = [
  "term_grid 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "users 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "zoneinfo_compiled 0.2.1 (git+https://github.com/rust-datetime/zoneinfo-compiled.git)",
  "zoneinfo_data 0.1.0 (git+https://github.com/rust-datetime/zoneinfo-data.git)",
 ]
 
@@ -39,6 +40,11 @@ name = "bitflags"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "byteorder"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "cmake"
 version = "0.1.12"
@@ -133,7 +139,7 @@ dependencies = [
  "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libssh2-sys 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "openssl-sys 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "openssl-sys 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -153,7 +159,7 @@ dependencies = [
  "cmake 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "openssl-sys 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "openssl-sys 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -199,7 +205,7 @@ version = "0.1.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "rand 0.3.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -222,7 +228,7 @@ dependencies = [
 
 [[package]]
 name = "openssl-sys"
-version = "0.7.5"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "gdi32-sys 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -265,7 +271,7 @@ dependencies = [
 
 [[package]]
 name = "rustc-serialize"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -316,7 +322,7 @@ version = "0.2.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "uuid 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -343,7 +349,7 @@ version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "rand 0.3.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-serialize 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -365,6 +371,15 @@ dependencies = [
  "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "zoneinfo_compiled"
+version = "0.2.1"
+source = "git+https://github.com/rust-datetime/zoneinfo-compiled.git#4ba145058702e68c322e8c822c3cf067b2b201f9"
+dependencies = [
+ "byteorder 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "datetime 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "zoneinfo_data"
 version = "0.1.0"

Cargo.toml

@@ -37,3 +37,6 @@ optional = true
 
 [dependencies.zoneinfo_data]
 git = "https://github.com/rust-datetime/zoneinfo-data.git"
+
+[dependencies.zoneinfo_compiled]
+git = "https://github.com/rust-datetime/zoneinfo-compiled.git"

src/main.rs

@@ -14,6 +14,7 @@ extern crate scoped_threadpool;
 extern crate term_grid;
 extern crate unicode_width;
 extern crate users;
+extern crate zoneinfo_compiled;
 extern crate zoneinfo_data;
 
 #[cfg(feature="git")] extern crate git2;

src/output/details.rs

@@ -82,6 +82,7 @@ use ansi_term::Style;
 use datetime::fmt::DateFormat;
 use datetime::{LocalDateTime, DatePiece};
 use datetime::TimeZone;
+use zoneinfo_compiled::CompiledData;
 use zoneinfo_data::ZoneinfoData;
 
 use locale;
@@ -168,12 +169,21 @@ impl Default for Environment<UsersCache> {
             current_year: LocalDateTime::now().year(),
             numeric:      locale::Numeric::load_user_locale().unwrap_or_else(|_| locale::Numeric::english()),
             time:         locale::Time::load_user_locale().unwrap_or_else(|_| locale::Time::english()),
-            tz:           TimeZone::system().expect("Unable to determine time zone"),
+            tz:           determine_time_zone().expect("Unable to determine time zone"),
             users:        Mutex::new(UsersCache::new()),
         }
     }
 }
 
+fn determine_time_zone() -> Result<TimeZone> {
+    if let Some(system_zone) = TimeZone::system() {
+        Ok(system_zone)
+    }
+    else {
+        TimeZone::from_file("/etc/localtime")
+    }
+}
+
 impl Details {
 
     /// Print the details of the given vector of files -- all of which will