Done with lipmaalinks, but probably not partial verification.

README.md

@@ -55,6 +55,7 @@ Eg: `pigeon identity show` becomes `./pigeon-cli show`.
  - [X] Run Flog / Flay and friends to find duplications. Will aid in port to other languages.
  - [X] Make all methods private except those required for the CLI.
  - [ ] Add Lipmaa links like the Bamboo folks do.
+ - [ ] Verification of `depth` and `lipmaa` may need a re-look to support partial verification.
  - [ ] Make the switch to LevelDB, RocksDB, [UNQLite](https://unqlite.org/features.html) or similar (currently using Ruby PStore).
  - [ ] Make CLI names consistent with API names. Eg: find vs. read.
  - [ ] Create regexes in ::Lexer using strings and Regexp.new() for cleaner regexes.

dist/pigeon.rb

@@ -87,7 +87,7 @@ module Pigeon
       # The original lipmaa function returns -1 for 0
       # but that does not mesh well with our serialization
       # scheme. Comments welcome on this one.
-      return 0 if n == 0 # Prevent -1 return value.
+      return 0 if n < 1 # Prevent -1, division by zero etc..
 
       m, po3, x = 1, 3, n
       # find k such that (3^k - 1)/2 >= n

dist/pigeon/lexer.rb

@@ -100,7 +100,7 @@ module Pigeon
       end
 
       if scanner.scan(LIPMAA)
-        depth = scanner.matched.chomp.gsub("depth ", "").to_i
+        depth = scanner.matched.chomp.gsub("lipmaa ", "").to_i
         @tokens << [:LIPMAA, depth]
         return
       end

dist/pigeon/message.rb

@@ -39,7 +39,7 @@ module Pigeon
 
     def save!
       return store.read_message(multihash) if store.message?(multihash)
-      verify_depth_prev_and_depth
+      verify_counted_fields
       verify_signature
       self.freeze
       store.save_message(self)
@@ -53,11 +53,14 @@ module Pigeon
       end
     end
 
-    def verify_depth_prev_and_depth
+    def verify_counted_fields
       count = store.get_message_count_for(author.multihash)
       expected_prev = store.get_message_by_depth(author.multihash, count - 1) || Pigeon::NOTHING
       assert("depth", count, depth)
-      assert("lipmaa", Helpers.lipmaa(count), lipmaa)
+      # TODO: Re-visit this. Our current verification method
+      # is probably too strict and won't allow for partial
+      # verification of feeds.
+      assert("lipmaa", Helpers.lipmaa(depth), lipmaa)
       assert("prev", prev, expected_prev)
     end
 
@@ -83,16 +86,6 @@ module Pigeon
       @signature = signature
     end
 
-    def params
-      { author: @author,
-        kind: @kind,
-        body: @body,
-        depth: @depth,
-        prev: @prev,
-        lipmaa: @lipmaa,
-        signature: @signature }
-    end
-
     def template
       MessageSerializer.new(self)
     end

spec/pigeon/helpers_spec.rb

@@ -1,4 +1,23 @@
 RSpec.describe Pigeon::Helpers do
+  it "creates lipmalinks" do
+    [
+      [-1, 0],
+      [0, 0],
+      [1, 0],
+      [2, 1],
+      [3, 2],
+      [4, 1],
+      [5, 4],
+      [6, 5],
+      [7, 6],
+      [8, 4],
+      [13, 4],
+    ].map do |(input, expected)|
+      actual = Pigeon::Helpers.lipmaa(input)
+      expect(actual).to eq(expected)
+    end
+  end
+
   it "handles Crockford Base 32 values" do
     10.times do
       raw_bytes = SecureRandom.random_bytes(32)

spec/pigeon/message_spec.rb

@@ -50,6 +50,7 @@ RSpec.describe Pigeon::Message do
       "kind unit_test",
       "prev NONE",
       "depth 0",
+      "lipmaa 0",
       "",
       "a:\"bar\"",
       "b:&CHHABX8Q9D9Q0BY2BBZ6FA7SMAFNE9GGMSDTZVZZC9TK2N9F15QG.sha256",