From 11b2e8c747a454ba3702ce2ea41ccc212241ee5b Mon Sep 17 00:00:00 2001
From: Rick Carlino <rick.carlino@gmail.com>
Date: Wed, 13 May 2020 07:30:11 -0500
Subject: [PATCH] Problems with new Pigeon::StringScanner

---
 README.md                    | 16 ++++++----------
 lib/pigeon.rb                |  1 +
 lib/pigeon/lexer.rb          | 14 +++++++++++++-
 lib/pigeon/string_scanner.rb | 28 ++++++++++++++++++++++++++++
 4 files changed, 48 insertions(+), 11 deletions(-)
 create mode 100644 lib/pigeon/string_scanner.rb

diff --git a/README.md b/README.md
index 9191f4a..d92ea76 100644
--- a/README.md
+++ b/README.md
@@ -46,18 +46,14 @@ See `kitchen_sink.sh` examples.
 
 # Current Status
 
- - [X] Create a contact email for project outsiders (and maybe a developer email list?)
- - [X] Update README.md
- - [X] Update Ruby API docs
- - [X] Update blobs spec to clear out blob folder every time it runs.
- - [ ] Oops, `lipmaa` field needs to be a hash, not an integer!
- - [ ] Change `@`, `%`, `&` to `feed.`, `mesg.`, `blob.`, respectively. Better readability, easier onboarding, URL friendly.
- - [ ] Change draft and message templates to render headers in this order: `author`, `prev`, `lipmaa`, `depth`, `kind`.
- - [ ] Make location of blob folder configurable?
- - [ ] Update Dev docs in protocol spec to reflect changes to `lipmaa` header.
- - [ ] Update spec document CLI usage examples to reflect API changes in 2020.
+ - [X] Oops, `lipmaa` field needs to be a hash, not an integer!
  - [ ] BUG: Keys that start with a carriage return (`\n`) freeze tokenizer.
  - [ ] Convert literals to constants, remove unused locals, reduce duplication, run linter.
+ - [ ] Change message templates to render headers in this order: `author`, `prev`, `lipmaa`, `depth`, `kind`.
+ - [ ] Make location of blob folder configurable?
+ - [ ] Change `@`, `%`, `&` to `feed.`, `mesg.`, `blob.`, respectively. Better readability, easier onboarding, URL friendly.
+ - [ ] Update Dev docs in protocol spec to reflect changes to `lipmaa` header.
+ - [ ] Update spec document CLI usage examples to reflect API changes in 2020.
  - [ ] 100% class / module documentation
  - [ ] Run a [terminology extraction tool](https://www.visualthesaurus.com/vocabgrabber/#) on the documentation and write a glossary of terms.
  - [ ] Publish to RubyGems
diff --git a/lib/pigeon.rb b/lib/pigeon.rb
index 2a052a2..2111af6 100644
--- a/lib/pigeon.rb
+++ b/lib/pigeon.rb
@@ -283,6 +283,7 @@ require_relative File.join("pigeon", "message_serializer.rb")
 require_relative File.join("pigeon", "draft_serializer.rb")
 require_relative File.join("pigeon", "message.rb")
 require_relative File.join("pigeon", "draft.rb")
+require_relative File.join("pigeon", "string_scanner.rb")
 require_relative File.join("pigeon", "lexer.rb")
 require_relative File.join("pigeon", "parser.rb")
 require_relative File.join("pigeon", "database.rb")
diff --git a/lib/pigeon/lexer.rb b/lib/pigeon/lexer.rb
index d8001b9..9784dd2 100644
--- a/lib/pigeon/lexer.rb
+++ b/lib/pigeon/lexer.rb
@@ -9,15 +9,17 @@ module Pigeon
     end
 
     def initialize(bundle_string)
-      @bundle_string = bundle_string
+      @bundle_string = bundle_string + "\n"
       @scanner = StringScanner.new(bundle_string)
       @tokens = []
       @state = HEADER
       @last_good = :START
+      @loops = 0
     end
 
     def tokenize
       until scanner.eos?
+        safety_check
         case @state
         when HEADER then do_header
         when BODY then do_body
@@ -30,6 +32,7 @@ module Pigeon
 
     def tokenize_unsigned(signature)
       until scanner.eos?
+        safety_check
         case @state
         when HEADER then do_header
         when BODY then do_body
@@ -42,6 +45,14 @@ module Pigeon
 
     private
 
+    def safety_check
+      if @loops > 1000
+        raise "RUNAWAY LOOP DETECTED"
+      else
+        @loops += 1
+      end
+    end
+
     attr_reader :bundle_string, :scanner, :tokens
     # TODO: Change all the `{40,90}` values in ::Lexer to real values
     # TODO: Create regexes using string and Regexp.new() for cleaner regexes.
@@ -167,6 +178,7 @@ module Pigeon
         @state = HEADER
         maybe_end_message!
         @last_good = :FOOTER_SEPERATOR
+        @loops = 0
         return
       end
 
diff --git a/lib/pigeon/string_scanner.rb b/lib/pigeon/string_scanner.rb
new file mode 100644
index 0000000..d9db7f3
--- /dev/null
+++ b/lib/pigeon/string_scanner.rb
@@ -0,0 +1,28 @@
+module Pigeon
+  class StringScanner
+    attr_reader :pos, :matched, :string
+    MAX_TOKEN_SIZE = 500
+
+    def initialize(string)
+      @string = string.freeze
+      @pos = 0
+      @matched = ""
+    end
+
+    def eos?
+      result = @pos == @string.length - 1
+      puts result ? "is eos" : "not eos"
+    end
+
+    def scan(regex)
+      puts "Scanning #{regex}"
+      @last = regex
+      match = regex.match(@string[@pos...MAX_TOKEN_SIZE])
+      if match
+        length = match.end(0)
+        @pos += length
+        @matched = match.values_at(0).first
+      end
+    end
+  end
+end