Add ability to define custom signatures

Gitrob will now look for a file at `~/.gitrobsignatures` which it
expects to be a JSON document that follows the same structure as the
main signatures.json file. If the signatures are valid, it will be
loaded into the BlobObserver.

lib/gitrob/blob_observer.rb

@@ -2,6 +2,8 @@ module Gitrob
   class BlobObserver
     SIGNATURES_FILE_PATH = File.expand_path(
       "../../../signatures.json", __FILE__)
+    CUSTOM_SIGNATURES_FILE_PATH = File.join(
+      Dir.home, ".gitrobsignatures")
 
     REQUIRED_SIGNATURE_KEYS = %w(part type pattern caption description)
     ALLOWED_TYPES           = %w(regex match)
@@ -30,23 +32,49 @@ module Gitrob
 
     def self.load_signatures!
       @signatures = []
-      JSON.load(File.read(SIGNATURES_FILE_PATH)).each do |signature|
+      signatures = JSON.load(File.read(SIGNATURES_FILE_PATH))
+      validate_signatures!(signatures)
+      signatures.each_with_index do |signature|
         @signatures << Signature.new(signature)
       end
-      validate_signatures!
     rescue CorruptSignaturesError => e
       raise e
     rescue
       raise CorruptSignaturesError, "Could not parse signature file"
     end
 
-    def self.validate_signatures!
+    def self.unload_signatures
+      @signatures = []
+    end
+
+    def self.custom_signatures?
+      File.exist?(CUSTOM_SIGNATURES_FILE_PATH)
+    end
+
+    def self.load_custom_signatures!
+      signatures = JSON.load(File.read(CUSTOM_SIGNATURES_FILE_PATH))
+      validate_signatures!(signatures)
+      signatures.each do |signature|
+        @signatures << Signature.new(signature)
+      end
+    rescue CorruptSignaturesError => e
+      raise e
+    rescue
+      raise CorruptSignaturesError, "Could not parse signature file"
+    end
+
+    def self.validate_signatures!(signatures)
       if !signatures.is_a?(Array) || signatures.empty?
         fail CorruptSignaturesError,
              "Signature file contains no signatures"
       end
-      signatures.each do |signature|
-        validate_signature!(signature)
+      signatures.each_with_index do |signature, index|
+        begin
+          validate_signature!(signature)
+        rescue CorruptSignaturesError => e
+          raise CorruptSignaturesError,
+                "Validation failed for Signature ##{index + 1}: #{e.message}"
+        end
       end
     end
 
@@ -58,7 +86,7 @@ module Gitrob
 
     def self.validate_signature_keys!(signature)
       REQUIRED_SIGNATURE_KEYS.each do |key|
-        unless signature.respond_to?(key)
+        unless signature.key?(key)
           fail CorruptSignaturesError,
                "Missing required signature key: #{key}"
         end
@@ -66,16 +94,16 @@ module Gitrob
     end
 
     def self.validate_signature_type!(signature)
-      unless ALLOWED_TYPES.include?(signature.type)
+      unless ALLOWED_TYPES.include?(signature["type"])
         fail CorruptSignaturesError,
-             "Invalid signature type: #{signature.type}"
+             "Invalid signature type: #{signature['type']}"
       end
     end
 
     def self.validate_signature_part!(signature)
-      unless ALLOWED_PARTS.include?(signature.part)
+      unless ALLOWED_PARTS.include?(signature["part"])
         fail CorruptSignaturesError,
-             "Invalid signature part: #{signature.part}"
+             "Invalid signature part: #{signature['part']}"
       end
     end
 

lib/gitrob/cli/commands/analyze.rb

@@ -40,6 +40,15 @@ module Gitrob
           task("Loading signatures...", true) do
             Gitrob::BlobObserver.load_signatures!
           end
+
+          if Gitrob::BlobObserver.custom_signatures?
+            task("Loading custom signatures...", true) do
+              Gitrob::BlobObserver.load_custom_signatures!
+            end
+            info("Please consider contributing your custom signatures to the " \
+                 "Gitrob project.")
+          end
+          info("Loaded #{Gitrob::BlobObserver.signatures.count} signatures")
         end
 
         def start_web_server