Re: library usage

[Eric Wong <e@80x24.org>]

Dimid Duchovny <dimidd@gmail.com> wrote:
> Thank you for the quick reply. IMHO, the best option would be indeed
> to add an optional proc to thread! . If nil, it would be equivalent to
> the noop order!.

Thanks for the feedback, I've pushed the following out and will
likely release 1.1.0 in a day or two (in case you notice any
other things wrong).

I was planning on writing something else using this, but it's on
the backburner for now; so you might be the only user at the
moment :)

https://80x24.org/msgthr.git/patch?id=d06d8c221be5b82d00da821323fb6d1889e58105
-------------8<------------
Subject: simplify API to avoid (and raise on) user errors

This fixes our API to match the documentation in making
Msgthr#order! optional.  Furthermore, the block previously
passed to Msgthr#order! may now be passed to Msgthr#thread!
instead.

We accomplish this by tracking internal state explicitly, so a
Msgthr::StateError exception will be raised when methods are
called in an unsupported order.  This internal state is reset
with Msgthr#clear.

For users who truly do not care about ordering, Msgthr#walk_thread
may be called immediately after the last call to Msgthr#add.

Thanks to Dimid Duchovny for the feedback which led to this:
https://80x24.org/msgthr-public/CANKvuDc2mkxLuh+3+WXWfMXzxK2bShNesrD5xLocGOD1RybbwQ@mail.gmail.com/
---
 lib/msgthr.rb           | 59 +++++++++++++++++++++++++++++++--------------
 lib/msgthr/container.rb |  6 ++---
 test/test_msgthr.rb     | 64 ++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 107 insertions(+), 22 deletions(-)

diff --git a/lib/msgthr.rb b/lib/msgthr.rb
index ea63731..1517f28 100644
--- a/lib/msgthr.rb
+++ b/lib/msgthr.rb
@@ -7,8 +7,7 @@
 #
 # * use Msgthr.new to create a new object
 # * use Msgthr#add! for every message you have
-# * use Msgthr#thread! to perform threading operations
-# * optionally, use Msgthr#order! to sort messages
+# * use Msgthr#thread! to perform threading and (optionally) sort
 # * use Msgthr#walk_thread to iterate through the threaded tree
 #
 # See https://80x24.org/msgthr/README for more info
@@ -20,43 +19,39 @@ class Msgthr
   # calling Msgthr#thread!
   attr_reader :rootset
 
+  # raised when methods are called in an unsupported order
+  StateError = Class.new(RuntimeError)
+
   # Initialize a Msgthr object
   def initialize
     @id_table = {}
     @rootset = []
+    @state = :init # :init => :threaded => :ordered
   end
 
   # Clear internal data structures to save memory and prepare for reuse
   def clear
     @rootset.clear
     @id_table.clear
+    @state = :init
   end
 
   # Performs threading on the messages and returns the rootset
   # (set of message containers without parents).
   #
-  # Call this after all #add operations are complete.
-  # This does not sort, use #order! if sorting is necessary.
-  def thread!
-    ret = @rootset
-    @id_table.each_value { |cont| ret << cont if cont.parent.nil? }.clear
-    ret
-  end
-
-  # Performs an in-place sort on messages after thread!
-  # This is optional and intended to be called this only after #thread!
+  # Call this only after all #add operations are complete.
   #
-  # This takes a block which yields an array of Msgthr::Container
-  # objects for sorting.
+  # If given an optional block, it will perform an in-place sort
+  # using the block parameter.
   #
-  # To sort by unique +mid+ identifiers for each container:
+  # To thread and sort by unique +mid+ identifiers for each container:
   #
-  #   msgthr.order! { |ary| ary.sort_by!(&:mid) }
+  #   msgthr.thread! { |ary| ary.sort_by!(&:mid) }
   #
   # If your opaque message pointer contains a +time+ accessor which gives
   # a Time object:
   #
-  #   msgthr.order! do |ary|
+  #   msgthr.thread! do |ary|
   #     ary.sort_by! do |cont| # Msgthr::Container
   #       cur = cont.topmost
   #       cur ? cur.msg.time : Time.at(0)
@@ -67,16 +62,40 @@ class Msgthr
   # Msgthr::Container#mid, as any known missing messages (ghosts)
   # will still have a +mid+.  However, Msgthr::Container#topmost is
   # necessary if accessing Msgthr::Container#msg.
+  def thread!
+    raise StateError, "already #@state" if @state != :init
+    ret = @rootset
+    @id_table.each_value { |cont| ret << cont if cont.parent.nil? }.clear
+    @state = :threaded
+    order! { |ary| yield(ary) } if block_given?
+    ret
+  end
+
+  # Calling this method is unnecessary since msgthr 1.1.0.
+  # In previous releases, the #thread! did not support a block
+  # parameter for ordering.  This method remains for compatibility.
   def order!
+    case @state
+    when :init then raise StateError, "#thread! not called"
+    when :ordered then raise StateError, "already #@state"
+    # else @state == :threaded
+    end
+
     yield @rootset
     @rootset.each do |cont|
       # this calls Msgthr::Container#order!, which is non-recursive
       cont.order! { |children| yield(children) }
     end
+    @state = :ordered
+    @rootset
   end
 
   # non-recursively walk a set of messages after #thread!
-  # (and optionally, #order!)
+  # (and optionally, #order!).
+  #
+  # If you do not care about ordering, you may call this
+  # immediately after all #add operations are complete starting
+  # with msgthr 1.1.0
   #
   # This takes a block and yields 3 elements to it: +|level, container, index|+
   # for each message container.
@@ -95,6 +114,8 @@ class Msgthr
   #     printf("#{indent} % 3d. %s\n", index, subject)
   #   end
   def walk_thread
+    thread! if @state == :init
+    order! { |_| } if @state == :threaded
     i = -1
     q = @rootset.map { |cont| [ 0, cont, i += 1 ] }
     while tmp = q.shift
@@ -128,6 +149,8 @@ class Msgthr
   # calling this method to avoid wasting memory on hash keys.  Likewise
   # is true for any String objects in +refs+.
   def add(mid, refs, msg)
+    @state == :init or raise StateError, "cannot add when already #@state"
+
     cur = @id_table[mid] ||= Msgthr::Container.new(mid)
     cur.msg = msg
     refs or return
diff --git a/lib/msgthr/container.rb b/lib/msgthr/container.rb
index e51507c..fbff719 100644
--- a/lib/msgthr/container.rb
+++ b/lib/msgthr/container.rb
@@ -1,9 +1,9 @@
 # Copyright (C) 2016 all contributors <msgthr-public@80x24.org>
 # License: GPL-2.0+ <https://www.gnu.org/licenses/gpl-2.0.txt>
 
-# An internal container class, this is exposed for Msgthr#order!
-# and Msgthr#walk_thread APIs.  They should should not be initialized
-# in your own code.
+# An internal container class, this is exposed for Msgthr#thread!
+# Msgthr#order! and Msgthr#walk_thread APIs through block parameters.
+# They should should not be initialized in your own code.
 #
 # One container object will exist for every message you call Msgthr#add! on,
 # so there can potentially be many of these objects for large sets of
diff --git a/test/test_msgthr.rb b/test/test_msgthr.rb
index 19cec75..b14e135 100644
--- a/test/test_msgthr.rb
+++ b/test/test_msgthr.rb
@@ -11,8 +11,9 @@ class TestMsgthr < Test::Unit::TestCase
     thr.add('c', nil, 'c')
     thr.add('D', nil, 'D')
     thr.add('d', %w(missing), 'd')
-    thr.thread!
+    rset = thr.thread!
     rootset = thr.order! { |c| c.sort_by!(&:mid) }
+    assert_same rset, rootset
     assert_equal %w(D c missing), rootset.map(&:mid)
     assert_equal 'D', rootset[0].msg
     assert_equal %w(b), rootset[1].children.map(&:mid)
@@ -33,4 +34,65 @@ class TestMsgthr < Test::Unit::TestCase
 EOF
     assert_equal exp, out
   end
+
+  def test_order_in_thread
+    thr = Msgthr.new
+    thr.add(1, nil, 'a')
+    thr.add(2, [1], 'b')
+    thr.thread! do |ary|
+      ary.sort_by! do |cont|
+        cur = cont.topmost
+        cur ? cur : 0
+      end
+    end
+    out = ''
+    thr.walk_thread do |level, container, index|
+      msg = container.msg
+      out << "#{level} [#{index}] #{msg}\n"
+    end
+    exp = <<EOF.b
+0 [0] a
+1 [0] b
+EOF
+    assert_equal exp, out
+  end
+
+  def test_out_of_order
+    thr = Msgthr.new
+    thr.thread!
+    assert_raise(Msgthr::StateError) { thr.add(1, nil, 'a') }
+    thr.clear # make things good again, following should not raise:
+    thr.add(1, nil, 'a')
+    thr.thread!
+    assert_raise(Msgthr::StateError) { thr.thread! }
+
+    out = []
+    thr.walk_thread do |level, container, index|
+      msg = container.msg
+      out << "#{level} [#{index}] #{msg}"
+    end
+    assert_equal [ '0 [0] a' ], out
+    assert_raise(Msgthr::StateError) { thr.thread! { raise "DO NOT CALL" } }
+    assert_raise(Msgthr::StateError) { thr.order! { |_| raise "DO NOT CALL" } }
+
+    # this is legal, even if non-sensical
+    thr.clear
+    thr.walk_thread { |level, container, index| raise "DO NOT CALL" }
+  end
+
+  def test_short_add_to_walk
+    thr = Msgthr.new
+    thr.add(1, nil, 'a')
+    thr.add(2, [1], 'b')
+    out = ''
+    thr.walk_thread do |level, container, index|
+      msg = container.msg
+      out << "#{level} [#{index}] #{msg}\n"
+    end
+    exp = <<EOF.b
+0 [0] a
+1 [0] b
+EOF
+    assert_equal exp, out
+  end
 end
-- 
EW