From d125183ac4bb2a0f783a99c03abcd0e4f5f520d5 Mon Sep 17 00:00:00 2001
From: emmett <emmett@justin.tv>
Date: Thu, 2 Feb 2012 10:25:24 -0800
Subject: [PATCH] Backslashes are now quoted and unquoted correctly

---
 activerecord-postgres-hstore.gemspec      |  4 +--
 lib/activerecord-postgres-hstore/hash.rb  | 38 ++++++++++++++---------
 spec/activerecord-postgres-hstore_spec.rb | 18 ++++++++++-
 3 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/activerecord-postgres-hstore.gemspec b/activerecord-postgres-hstore.gemspec
index d75447b..12e1e21 100644
--- a/activerecord-postgres-hstore.gemspec
+++ b/activerecord-postgres-hstore.gemspec
@@ -5,10 +5,10 @@
 
 Gem::Specification.new do |s|
   s.name = %q{activerecord-postgres-hstore}
-  s.version = "0.3.0"
+  s.version = "0.3.1"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
-  s.authors = ["Juan Maiz", "Diogo Biazus"]
+  s.authors = ["Juan Maiz", "Diogo Biazus", "Emmett Shear"]
   s.date = %q{2011-12-28}
   s.description = %q{This gem adds support for the postgres hstore type. It is the _just right_ alternative for storing hashes instead of using seralization or dynamic tables.}
   s.email = %q{juanmaiz@gmail.com}
diff --git a/lib/activerecord-postgres-hstore/hash.rb b/lib/activerecord-postgres-hstore/hash.rb
index a3df13b..a5573d2 100644
--- a/lib/activerecord-postgres-hstore/hash.rb
+++ b/lib/activerecord-postgres-hstore/hash.rb
@@ -1,24 +1,34 @@
 class Hash
+  HSTORE_ESCAPED = /[,\s=>\\]/
+
+  # Escapes values such that they will work in an hstore string
+  def hstore_escape(str)
+    if str.nil?
+      return 'NULL'
+    end
+    
+    str = str.to_s.dup
+    # backslash is an escape character for strings, and an escape character for gsub, so you need 6 backslashes to get 2 in the output.
+    # see http://stackoverflow.com/questions/1542214/weird-backslash-substitution-in-ruby for the gory details
+    str.gsub!(/\\/, '\\\\\\')
+    # escape backslashes before injecting more backslashes
+    str.gsub!(/"/, '\"')
+    
+    if str =~ HSTORE_ESCAPED or str.empty?
+      str = '"%s"' % str
+    end
+    
+    return str
+  end
 
   # Generates an hstore string format. This is the format used
   # to insert or update stuff in the database.
   def to_hstore
     return "" if empty?
 
-    map { |idx, val| 
-      iv = [idx,val].map { |_| 
-        e = _.to_s.gsub(/"/, '\"')
-        if _.nil?
-          'NULL'
-        elsif e =~ /[,\s=>]/ || e.blank?
-          '"%s"' % e
-        else
-          e
-        end
-      }
-
-      "%s=>%s" % iv
-    } * ","
+    map do |idx, val| 
+      "%s=>%s" % [hstore_escape(idx), hstore_escape(val)]
+    end * ","
   end
 
   # If the method from_hstore is called in a Hash, it just returns self.
diff --git a/spec/activerecord-postgres-hstore_spec.rb b/spec/activerecord-postgres-hstore_spec.rb
index cf13697..0353f01 100644
--- a/spec/activerecord-postgres-hstore_spec.rb
+++ b/spec/activerecord-postgres-hstore_spec.rb
@@ -63,13 +63,29 @@
   end
 
   it "should quote keys and values correctly with combinations of single and double quotes" do
-    { %q("a') => %q(b "a' b) }.to_hstore.should eq(%q(\"a'=>"b \"a' b"))
+    { %q("a') => %q(b "a' b) }.to_hstore.should eq(%q("\"a'"=>"b \"a' b"))
   end
 
   it "should unquote keys and values correctly with combinations of single and double quotes" do
     %q("\"a'"=>"b \"a' b").from_hstore.should eq({%q("a') => %q(b "a' b)})
   end
 
+  it "should quote keys and values correctly with backslashes" do
+    { %q(\\) => %q(\\) }.to_hstore.should eq(%q("\\\\"=>"\\\\"))
+  end
+  
+  it "should unquote keys and values correctly with backslashes" do
+    %q("\\\\"=>"\\\\").from_hstore.should eq({ %q(\\) => %q(\\) })
+  end
+
+  it "should quote keys and values correctly with combinations of backslashes and quotes" do
+    { %q(' \\ ") => %q(" \\ ') }.to_hstore.should eq(%q("' \\\\ \""=>"\" \\\\ '"))
+  end
+
+  it "should unquote keys and values correctly with combinations of backslashes and quotes" do
+    %q("' \\\\ \""=>"\" \\\\ '").from_hstore.should eq({ %q(' \\ ") => %q(" \\ ') })
+  end
+
   it "should convert empty hash" do
     {}.to_hstore.should eq("")
   end