7 files changed, 121 insertions, 3 deletions
diff --git a/absl/time/internal/cctz/src/time_zone_info.cc b/absl/time/internal/cctz/src/time_zone_info.cc
index f2777d91..4f175d95 100644
--- a/absl/time/internal/cctz/src/time_zone_info.cc
+++ b/absl/time/internal/cctz/src/time_zone_info.cc
@@ -39,6 +39,7 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <fstream>
 #include <functional>
 #include <memory>
 #include <sstream>
@@ -649,7 +650,7 @@ std::unique_ptr<ZoneInfoSource> FileZoneInfoSource::Open(
 
   // Open the zoneinfo file.
   auto fp = FOpen(path.c_str(), "rb");
-  if (fp.get() == nullptr) return nullptr;
+  if (fp == nullptr) return nullptr;
   return std::unique_ptr<ZoneInfoSource>(new FileZoneInfoSource(std::move(fp)));
 }
 
@@ -674,7 +675,7 @@ std::unique_ptr<ZoneInfoSource> AndroidZoneInfoSource::Open(
   for (const char* tzdata : {"/data/misc/zoneinfo/current/tzdata",
                              "/system/usr/share/zoneinfo/tzdata"}) {
     auto fp = FOpen(tzdata, "rb");
-    if (fp.get() == nullptr) continue;
+    if (fp == nullptr) continue;
 
     char hbuf[24];  // covers header.zonetab_offset too
     if (fread(hbuf, 1, sizeof(hbuf), fp.get()) != sizeof(hbuf)) continue;
@@ -708,6 +709,69 @@ std::unique_ptr<ZoneInfoSource> AndroidZoneInfoSource::Open(
   return nullptr;
 }
 
+// A zoneinfo source for use inside Fuchsia components. This attempts to
+// read zoneinfo files from one of several known paths in a component's
+// incoming namespace. [Config data][1] is preferred, but package-specific
+// resources are also supported.
+//
+// Fuchsia's implementation supports `FileZoneInfoSource::Version()`.
+//
+// [1]:
+// https://fuchsia.dev/fuchsia-src/development/components/data#using_config_data_in_your_component
+class FuchsiaZoneInfoSource : public FileZoneInfoSource {
+ public:
+  static std::unique_ptr<ZoneInfoSource> Open(const std::string& name);
+  std::string Version() const override { return version_; }
+
+ private:
+  explicit FuchsiaZoneInfoSource(FilePtr fp, std::string version)
+      : FileZoneInfoSource(std::move(fp)), version_(std::move(version)) {}
+  std::string version_;
+};
+
+std::unique_ptr<ZoneInfoSource> FuchsiaZoneInfoSource::Open(
+    const std::string& name) {
+  // Use of the "file:" prefix is intended for testing purposes only.
+  const std::size_t pos = (name.compare(0, 5, "file:") == 0) ? 5 : 0;
+
+  // Prefixes where a Fuchsia component might find zoneinfo files,
+  // in descending order of preference.
+  const auto kTzdataPrefixes = {
+      "/config/data/tzdata/",
+      "/pkg/data/tzdata/",
+      "/data/tzdata/",
+  };
+  const auto kEmptyPrefix = {""};
+  const bool name_absolute = (pos != name.size() && name[pos] == '/');
+  const auto prefixes = name_absolute ? kEmptyPrefix : kTzdataPrefixes;
+
+  // Fuchsia builds place zoneinfo files at "<prefix><format><name>".
+  for (const std::string prefix : prefixes) {
+    std::string path = prefix;
+    if (!prefix.empty()) path += "zoneinfo/tzif2/";  // format
+    path.append(name, pos, std::string::npos);
+
+    auto fp = FOpen(path.c_str(), "rb");
+    if (fp == nullptr) continue;
+
+    std::string version;
+    if (!prefix.empty()) {
+      // Fuchsia builds place the version in "<prefix>revision.txt".
+      std::ifstream version_stream(prefix + "revision.txt");
+      if (version_stream.is_open()) {
+        // revision.txt should contain no newlines, but to be
+        // defensive we read just the first line.
+        std::getline(version_stream, version);
+      }
+    }
+
+    return std::unique_ptr<ZoneInfoSource>(
+        new FuchsiaZoneInfoSource(std::move(fp), std::move(version)));
+  }
+
+  return nullptr;
+}
+
 }  // namespace
 
 bool TimeZoneInfo::Load(const std::string& name) {
@@ -725,6 +789,7 @@ bool TimeZoneInfo::Load(const std::string& name) {
       name, [](const std::string& n) -> std::unique_ptr<ZoneInfoSource> {
         if (auto z = FileZoneInfoSource::Open(n)) return z;
         if (auto z = AndroidZoneInfoSource::Open(n)) return z;
+        if (auto z = FuchsiaZoneInfoSource::Open(n)) return z;
         return nullptr;
       });
   return zip != nullptr && Load(zip.get());
diff --git a/absl/time/internal/cctz/src/time_zone_lookup.cc b/absl/time/internal/cctz/src/time_zone_lookup.cc
index efdea64b..898d04c1 100644
--- a/absl/time/internal/cctz/src/time_zone_lookup.cc
+++ b/absl/time/internal/cctz/src/time_zone_lookup.cc
@@ -28,6 +28,13 @@
 #include <vector>
 #endif
 
+#if defined(__Fuchsia__)
+#include <fuchsia/intl/cpp/fidl.h>
+#include <lib/async-loop/cpp/loop.h>
+#include <lib/sys/cpp/component_context.h>
+#include <zircon/types.h>
+#endif
+
 #include <cstdlib>
 #include <cstring>
 #include <string>
@@ -140,6 +147,48 @@ time_zone local_time_zone() {
   }
   CFRelease(tz_default);
 #endif
+#if defined(__Fuchsia__)
+  std::string primary_tz;
+  [&]() {
+    // Note: We can't use the synchronous FIDL API here because it doesn't
+    // allow timeouts; if the FIDL call failed, local_time_zone() would never
+    // return.
+
+    const zx::duration kTimeout = zx::msec(500);
+
+    // Don't attach to the thread because otherwise the thread's dispatcher
+    // would be set to null when the loop is destroyed, causing any other FIDL
+    // code running on the same thread to crash.
+    async::Loop loop(&kAsyncLoopConfigNeverAttachToThread);
+    std::unique_ptr<sys::ComponentContext> context =
+        sys::ComponentContext::Create();
+
+    fuchsia::intl::PropertyProviderHandle handle;
+    zx_status_t status = context->svc()->Connect(handle.NewRequest());
+    if (status != ZX_OK) {
+      return;
+    }
+
+    fuchsia::intl::PropertyProviderPtr intl_provider;
+    status = intl_provider.Bind(std::move(handle), loop.dispatcher());
+    if (status != ZX_OK) {
+      return;
+    }
+
+    intl_provider->GetProfile(
+        [&loop, &primary_tz](fuchsia::intl::Profile profile) {
+          if (!profile.time_zones().empty()) {
+            primary_tz = profile.time_zones()[0].id;
+          }
+          loop.Quit();
+        });
+    loop.Run(zx::deadline_after(kTimeout));
+  }();
+
+  if (!primary_tz.empty()) {
+    zone = primary_tz.c_str();
+  }
+#endif
 
   // Allow ${TZ} to override to default zone.
   char* tz_env = nullptr;
diff --git a/absl/time/internal/cctz/src/time_zone_lookup_test.cc b/absl/time/internal/cctz/src/time_zone_lookup_test.cc
index 8751b346..0226ab71 100644
--- a/absl/time/internal/cctz/src/time_zone_lookup_test.cc
+++ b/absl/time/internal/cctz/src/time_zone_lookup_test.cc
@@ -1027,8 +1027,12 @@ TEST(MakeTime, SysSecondsLimits) {
 #endif
     const year_t min_tm_year = year_t{std::numeric_limits<int>::min()} + 1900;
     tp = convert(civil_second(min_tm_year, 1, 1, 0, 0, 0), cut);
+#if defined(__Fuchsia__)
+    // Fuchsia's gmtime_r() fails on extreme negative values (fxbug.dev/78527).
+#else
     EXPECT_EQ("-2147481748-01-01T00:00:00+00:00", format(RFC3339, tp, cut));
 #endif
+#endif
   }
 }
 
diff --git a/absl/time/internal/cctz/testdata/version b/absl/time/internal/cctz/testdata/version
index 51191b57..8ee898ba 100644
--- a/absl/time/internal/cctz/testdata/version
+++ b/absl/time/internal/cctz/testdata/version
@@ -1 +1 @@
-2021c
+2021e
diff --git a/absl/time/internal/cctz/testdata/zoneinfo/Asia/Gaza b/absl/time/internal/cctz/testdata/zoneinfo/Asia/Gaza
index 58e9fdf4..ccc57c9c 100644
--- a/absl/time/internal/cctz/testdata/zoneinfo/Asia/Gaza
+++ b/absl/time/internal/cctz/testdata/zoneinfo/Asia/Gaza
diff --git a/absl/time/internal/cctz/testdata/zoneinfo/Asia/Hebron b/absl/time/internal/cctz/testdata/zoneinfo/Asia/Hebron
index aeda06b5..906d8d5c 100644
--- a/absl/time/internal/cctz/testdata/zoneinfo/Asia/Hebron
+++ b/absl/time/internal/cctz/testdata/zoneinfo/Asia/Hebron
diff --git a/absl/time/internal/cctz/testdata/zoneinfo/Pacific/Fiji b/absl/time/internal/cctz/testdata/zoneinfo/Pacific/Fiji
index e3934e42..8b2dd52b 100644
--- a/absl/time/internal/cctz/testdata/zoneinfo/Pacific/Fiji
+++ b/absl/time/internal/cctz/testdata/zoneinfo/Pacific/Fiji