From 702e3ad47738363ab847f43155e047c7c6612f80 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Mon, 29 Jan 2018 00:43:45 +0000
Subject: player: support guessing encodings for comments

This can be helpful for end users and is close to what other
players use.  We can fallback to Encoding.default_external by
default (typically UTF-8) and then again using `charlock_holmes'
if installed.

Note: path names remain binary, because that's how proper
filesystems operate.
---
 lib/dtas/encoding.rb | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 lib/dtas/encoding.rb

(limited to 'lib/dtas/encoding.rb')

diff --git a/lib/dtas/encoding.rb b/lib/dtas/encoding.rb
new file mode 100644
index 0000000..71c877f
--- /dev/null
+++ b/lib/dtas/encoding.rb
@@ -0,0 +1,58 @@
+# Copyright (C) 2018 all contributors <dtas-all@nongnu.org>
+# License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
+# frozen_string_literal: true
+
+# This module gets included in DTAS
+module DTAS::Encoding # :nodoc:
+  def self.extended(mod)
+    mod.instance_eval { @charlock_holmes = nil}
+  end
+
+private
+
+  def try_enc_harder(str, enc, old) # :nodoc:
+    case @charlock_holmes
+    when nil
+      begin
+        require 'charlock_holmes'
+        @charlock_holmes = CharlockHolmes::EncodingDetector.new
+      rescue LoadError
+        warn "`charlock_holmes` gem not available for encoding detection"
+        @charlock_holmes = false
+      end
+    when false
+      enc_fallback(str, enc, old)
+    else
+      res = @charlock_holmes.detect(str)
+      if det = res[:ruby_encoding]
+        str.force_encoding(det)
+        warn "charlock_holmes detected #{str.inspect} as #{det}..."
+        str.valid_encoding? or enc_fallback(str, det, old)
+      else
+        enc_fallback(str, enc, old)
+      end
+    end
+    str
+  end
+
+  def enc_fallback(str, enc, old) # :nodoc:
+    str.force_encoding(old)
+    warn "could not detect encoding for #{str.inspect} (not #{enc})"
+  end
+
+public
+
+  def try_enc(str, enc, harder = true) # :nodoc:
+    old = str.encoding
+    return str if old == enc
+    str.force_encoding(enc)
+    unless str.valid_encoding?
+      if harder
+        try_enc_harder(str, enc, old)
+      else
+        enc_fallback(str, enc, old)
+      end
+    end
+    str
+  end
+end
-- 
cgit v1.2.3-24-ge0c7