Store external storage index in time zones

src/TimeZones.jl

@@ -55,6 +55,7 @@ include("indexable_generator.jl")
 
 include("class.jl")
 include("utcoffset.jl")
+include("external.jl")
 include(joinpath("types", "timezone.jl"))
 include(joinpath("types", "fixedtimezone.jl"))
 include(joinpath("types", "variabletimezone.jl"))

src/external.jl

@@ -0,0 +1,15 @@
+struct ExternalField{T}
+    table::Dict{T,Int}
+    data::Vector{T}
+end
+
+ExternalField{T}() where T = ExternalField{T}(Dict{T,Int}(), Vector{T}())
+
+function add!(x::ExternalField{T}, val::T) where T
+    get!(x.table, val) do
+        push!(x.data, val)
+        lastindex(x.data)
+    end
+end
+
+Base.getindex(x::ExternalField, i::Int) = x.data[i]

src/types/fixedtimezone.jl

@@ -29,9 +29,20 @@ const FIXED_TIME_ZONE_REGEX = r"""
 
 A `TimeZone` with a constant offset for all of time.
 """
-struct FixedTimeZone <: TimeZone
+mutable struct FixedTimeZone <: TimeZone
     name::String
     offset::UTCOffset
+    index::Int
+
+    function FixedTimeZone(name::String, utc_offset::UTCOffset)
+        tz = new(name, utc_offset)
+        tz.index = add!(_TIME_ZONES, tz)
+        return tz
+    end
+end
+
+function FixedTimeZone(name::AbstractString, utc_offset::UTCOffset)
+    FixedTimeZone(convert(String, name), utc_offset)
 end
 
 """
@@ -48,6 +59,21 @@ function FixedTimeZone(name::AbstractString, utc_offset::Second, dst_offset::Sec
     FixedTimeZone(name, UTCOffset(utc_offset, dst_offset))
 end
 
+# Overload serialization to ensure that `FixedTimeZone` serialization doesn't transfer
+# state information which is specific to the current Julia process.
+function Serialization.serialize(s::AbstractSerializer, tz::FixedTimeZone)
+    Serialization.serialize_type(s, typeof(tz))
+    serialize(s, tz.name)
+    serialize(s, tz.offset)
+end
+
+function Serialization.deserialize(s::AbstractSerializer, ::Type{FixedTimeZone})
+    name = deserialize(s)
+    offset = deserialize(s)
+
+    return FixedTimeZone(name, offset)
+end
+
 # https://en.wikipedia.org/wiki/ISO_8601#Coordinated_Universal_Time_(UTC)
 const UTC_ZERO = FixedTimeZone("Z", 0)
 
@@ -95,3 +121,17 @@ end
 
 name(tz::FixedTimeZone) = tz.name
 rename(tz::FixedTimeZone, name::AbstractString) = FixedTimeZone(name, tz.offset)
+
+function Base.:(==)(a::FixedTimeZone, b::FixedTimeZone)
+    return a.name == b.name && a.offset == b.offset
+end
+
+function Base.hash(tz::FixedTimeZone, h::UInt)
+    h = hash(:timezone, h)
+    h = hash(tz.name, h)
+    return h
+end
+
+function Base.isequal(a::FixedTimeZone, b::FixedTimeZone)
+    return isequal(a.name, b.name) && isequal(a.offset, b.offset)
+end

src/types/timezone.jl

@@ -1,4 +1,5 @@
 const TIME_ZONE_CACHE = Dict{String,Tuple{TimeZone,Class}}()
+const _TIME_ZONES = ExternalField{TimeZone}()
 
 """
     TimeZone(str::AbstractString) -> TimeZone

src/types/variabletimezone.jl

@@ -5,21 +5,49 @@ end
 
 Base.isless(a::Transition, b::Transition) = isless(a.utc_datetime, b.utc_datetime)
 
+function Base.:(==)(a::Transition, b::Transition)
+    return a.utc_datetime == b.utc_datetime && a.zone == b.zone
+end
+
+function Base.isequal(a::Transition, b::Transition)
+    return isequal(a.utc_datetime, b.utc_datetime) && isequal(a.zone, b.zone)
+end
+
 """
     VariableTimeZone
 
 A `TimeZone` with an offset that changes over time.
 """
-struct VariableTimeZone <: TimeZone
+mutable struct VariableTimeZone <: TimeZone
     name::String
     transitions::Vector{Transition}
     cutoff::Union{DateTime,Nothing}
+    index::Int
 
     function VariableTimeZone(name::AbstractString, transitions::Vector{Transition}, cutoff::Union{DateTime,Nothing}=nothing)
-        new(name, transitions, cutoff)
+        tz = new(name, transitions, cutoff)
+        tz.index = add!(_TIME_ZONES, tz)
+        return tz
     end
 end
 
+# Overload serialization to ensure that `VariableTimeZone` serialization doesn't transfer
+# state information which is specific to the current Julia process.
+function Serialization.serialize(s::AbstractSerializer, tz::VariableTimeZone)
+    Serialization.serialize_type(s, typeof(tz))
+    serialize(s, tz.name)
+    serialize(s, tz.transitions)
+    serialize(s, tz.cutoff)
+end
+
+function Serialization.deserialize(s::AbstractSerializer, ::Type{VariableTimeZone})
+    name = deserialize(s)
+    transitions = deserialize(s)
+    cutoff = deserialize(s)
+
+    return VariableTimeZone(name, transitions, cutoff)
+end
+
 name(tz::VariableTimeZone) = tz.name
 
 function rename(tz::VariableTimeZone, name::AbstractString)

src/types/zoneddatetime.jl

@@ -1,12 +1,5 @@
 using Dates: AbstractDateTime, argerror, validargs
 
-# Stores non-bits data outside of the `ZonedDateTime` structure
-const _ZDT_FIELDS = Vector{Tuple{TimeZone,FixedTimeZone}}()
-
-# Stored indexes into `_ZDT_FIELDS`
-const _TZ_INDEX = Dict{Tuple{TimeZone,FixedTimeZone},Int}()
-
-
 # """
 #     ZonedDateTime
 
@@ -16,38 +9,26 @@ const _TZ_INDEX = Dict{Tuple{TimeZone,FixedTimeZone},Int}()
 struct ZonedDateTime <: AbstractDateTime
     utc_datetime::DateTime
     _tz_index::Int
+    _zone_index::Int
 
     function ZonedDateTime(utc_datetime::DateTime, timezone::TimeZone, zone::FixedTimeZone)
-        return new(utc_datetime, _tz_index(timezone, zone))
+        return new(utc_datetime, timezone.index, zone.index)
     end
 
     function ZonedDateTime(utc_datetime::DateTime, timezone::VariableTimeZone, zone::FixedTimeZone)
         if timezone.cutoff !== nothing && utc_datetime >= timezone.cutoff
             throw(UnhandledTimeError(timezone))
         end
 
-        return new(utc_datetime, _tz_index(timezone, zone))
-    end
-end
-
-function _tz_index(tz::TimeZone, zone::FixedTimeZone)
-    t = (tz, zone)
-
-    i = get!(_TZ_INDEX, t) do
-        push!(_ZDT_FIELDS, t)
-        lastindex(_ZDT_FIELDS)
+        return new(utc_datetime, timezone.index, zone.index)
     end
-
-    return i
 end
 
 function Base.getproperty(zdt::ZonedDateTime, field::Symbol)
     if field === :zone
-        tz, zone = _ZDT_FIELDS[getfield(zdt, :_tz_index)]
-        return zone
+        return _TIME_ZONES[getfield(zdt, :_zone_index)]::FixedTimeZone
     elseif field === :timezone
-        tz, zone = _ZDT_FIELDS[getfield(zdt, :_tz_index)]
-        return tz
+        return _TIME_ZONES[getfield(zdt, :_tz_index)]::TimeZone
     else
         return getfield(zdt, field)
     end