lib/csvsql.rb in csvsql-0.1.5 vs lib/csvsql.rb in csvsql-0.2.0

@@ -2,24 +2,94 @@
 
 require "csvsql/version"
 
 require 'csv'
 require 'sqlite3'
+require 'digest'
+require 'fileutils'
 
 require 'csvsql/db'
 require 'csvsql/tracker'
+require 'csvsql/command_runner'
 
 module Csvsql
-  def self.execute(sql, csv_data, opts = {})
-    encoding = opts.delete(:encoding)
-    csvdb = Csvsql::Db.new(opts)
-    csvdb.import(csv_data, encoding: encoding)
+  extend self
+
+  CACHE_DIR = File.join(Dir.home, '.csvsql_cache')
+  FileUtils.mkdir_p(CACHE_DIR) unless Dir.exists?(CACHE_DIR)
+
+  def execute(sql, csv_data, opts = {})
+    csvdb = init_data(csv_data, opts)
     pst = Csvsql::Tracker.commit(:execute_query_sql) do
       csvdb.prepare(sql)
     end
     Csvsql::Tracker.commit(:output_format)
     CSV.generate do |csv|
       csv << pst.columns.zip(pst.types).map { |c| c.compact.join(':') }
       pst.each { |line| csv << line }
     end.tap { Csvsql::Tracker.commit(:output_format) }
+  end
+
+  def self.clear_cache!
+    FileUtils.rm_f(Dir.glob(File.join(CACHE_DIR, '*')))
+  end
+
+  private
+
+  def init_data(csv_data, opts)
+    encoding = opts.delete(:encoding)
+    use_cache = opts.delete(:use_cache)
+    csvdb = Csvsql::Db.new(opts)
+
+    unless use_cache
+      csvdb.import(csv_data, encoding: encoding)
+      return csvdb
+    end
+
+    case csv_data
+    when StringIO, IO
+      # nothing
+    when Hash
+      dbs = []
+      csv_data.each do |dbname, csv_path|
+        dbs << [dbname, csvdb.init_db(get_db_cache_path(csv_path) || '')]
+        csvdb.import(csv_path, encoding: encoding)
+      end
+      dbs.each do |dbname, db|
+        csvdb.execute("ATTACH DATABASE '#{db.filename}' AS #{dbname};")
+      end
+    else
+      csvdb.init_db(get_db_cache_path(csv_data) || '')
+      csvdb.import(csv_data, encoding: encoding)
+    end
+
+    csvdb
+  end
+
+  def get_db_cache_path(csv_path)
+    csv_path = csv_path || ''
+    return unless File.exist?(csv_path)
+
+    stat = File.stat(csv_path)
+    filename = Digest::SHA2.hexdigest(File.absolute_path(csv_path)) + '.cache'
+    file_stat = [File.absolute_path(csv_path), stat.size, stat.ctime].join("\n")
+    stat_path = File.join(CACHE_DIR, filename.gsub(/\.cache$/, '.stat'))
+    cache_path = File.join(CACHE_DIR, filename)
+
+    if File.exist?(stat_path)
+      if File.read(stat_path) == file_stat
+        cache_path
+      else
+        if update_cb
+          update_cb.call
+        else
+          FileUtils.rm(cache_path)
+        end
+        File.write(stat_path, file_stat)
+        cache_path
+      end
+    else
+      File.write(stat_path, file_stat)
+      cache_path
+    end
   end
 end