Class: FluentQuery::Queries::Processor

Inherits:
Object
  • Object
show all
Defined in:
lib/fluent-query/queries/processor.rb

Overview

Query processor.

Its primary aim is to dive processing methods from query object as is. In fact, defines something as processing session.

Constant Summary collapse

COLUMN_REPLACEMENT =

Indicates column replacement to perform. (Flag.)

2
STRING_REPLACEMENT =

Indicates string replacement to perform. (Flag.)

1
FORMATTING_REPLACEMENT =

Indicates formatting directive replacements to perform. (Flag.)

4
FORMATTING_DIRECTIVE =

Describes formatting directive.

/%%(?:[islbfdt]|sql|and|or)(?:[^\w]|$)/
COLUMN_DIRECTIVE =

Describes column directive.

/(?:^|\.|[^\'"\w\\])?\[(?:[\w\.]*[^\\\W])\](?:[^\'"\w]|\.|$)/
STRING_DIRECTIVE =

Describes string directive.

/(?:^|[^\\])"/
FORMATTING_DIRECTIVE_SIMPLE =

Holds simple column definition.

/%%\w+/
COLUMN_DIRECTIVE_SIMPLE =

Holds simple column definition.

/\[.+\]/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(driver) ⇒ Processor

Returns a new instance of Processor.



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# File 'lib/fluent-query/queries/processor.rb', line 111

def initialize(driver)
    @driver = driver
end

Instance Attribute Details

#driver ⇒ Object (readonly)

Returns the value of attribute driver.



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# File 'lib/fluent-query/queries/processor.rb', line 97

def driver
  @driver
end

Instance Method Details

#compile(string) ⇒ Object

Compiles the string.



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# File 'lib/fluent-query/queries/processor.rb', line 386

def compile(string)
    self.compiler.compile(string)
end

#compiler ⇒ Object

Returns compiler.



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# File 'lib/fluent-query/queries/processor.rb', line 374

def compiler
    if @_compiler.nil?
        @_compiler = FluentQuery::Compiler::new(self)
    end
    
    @_compiler
end

#expander ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 344

def expander
    if @__fluent_expander.nil?
        @__fluent_expander = self.class::FORMATTING_DIRECTIVE            
    end

    @__fluent_expander
end

#null ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 335

def null
    @driver.null
end

#process_array(array, glue = ",") ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 123

def process_array(array, glue = ",")
    result = array.map do |i| 
        self.quote_value(i)
    end
    return result.join(glue + " ")
end

#process_directive(directive, argument = nil, replacements = 7) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 299

def process_directive(directive, argument = nil, replacements = 7)
    if (replacements & self.class::COLUMN_REPLACEMENT > 0) and (directive[0].ord == 91)           # "[", Column directive
        result = directive.gsub(self.class::COLUMN_DIRECTIVE_SIMPLE) { |value| self.quote_identifier(value[1..-2]) }
    elsif (replacements & self.class::STRING_REPLACEMENT > 0) and (directive[-1].ord == 34)           # "\"", String directive
        result = directive.gsub('"', @driver.quote_string("").last)
    elsif (replacements & self.class::FORMATTING_REPLACEMENT > 0) and (directive[0..1] == "%%")   # Formatting directive
        result = directive.gsub(self.class::FORMATTING_DIRECTIVE_SIMPLE) { |value| self.process_formatting(value[2..-1], argument) }
    else
        result = directive
    end

    return result
end

#process_formatted(sequence, mode = :build) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 242

def process_formatted(sequence, mode = :build)
    count = sequence.length
    i = 0
    output = ""
                                
    replacer_settings = self.class::COLUMN_REPLACEMENT | self.class::STRING_REPLACEMENT
    expander_settings = self.class::FORMATTING_REPLACEMENT
    
    while i < count 
        item = sequence[i]
         
        ##
        
        if item.kind_of? String
            item = item.dup
        
            # Calls to each occurence of directive matching to directive
            #  finding expression directive processing. In each call increases
            #  sequence position counter so moves forward.

            if mode.in? [:compile, :build, :prepare]
                item.gsub!(self.replacer) do |directive| 
                    directive.strip!
                    self.process_directive(directive, nil, replacer_settings)
                end
            end
            
            if mode.in? [:finish, :build]
                item.gsub!(self.expander) do |directive| 
                    self.process_directive(directive, sequence[i += 1], expander_settings) 
                end
            end
            
            output << item

        elsif item.kind_of? Symbol
            output << self.quote_identifier(item)
            
        else
            output << item.to_s
            
        end

        output << " "
        i += 1
    end

    return output
    
end

#process_formatting(directive, argument) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 318

def process_formatting(directive, argument)
    proc = self.compiler.compile_formatting(directive)
    
    if proc
        output = proc.call(argument)
    else
        output = ""
    end
    
    return output
end

#process_hash(hash, glue = ",", equality = :comparing) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 143

def process_hash(hash, glue = ",", equality = :comparing)
    result = [ ]
    mode = equality
    
    hash.each_pair do |key, value|
        operator = @driver.quote_equality(value, mode)                        
        key = self.quote_identifier(key)
        value = self.quote_value(value)

        result << (key + " " + operator + " " + value)
    end

    return result.join(" " << glue << " ")
end

#process_identifiers(identifiers) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 226

def process_identifiers(identifiers)
    self.quote_identifiers(identifiers).join(", ")
end

#quote_identifier(identifier) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 207

def quote_identifier(identifier)
    @driver.quote_identifier(identifier.to_s)
end

#quote_identifiers(identifiers) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 216

def quote_identifiers(identifiers)
    identifiers.map { |i| self.quote_identifier(i) }
end

#quote_subquery(subquery) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 194

def quote_subquery(subquery)
    if subquery.kind_of? FluentQuery::Query
        subquery = subquery.build!
    end
    
    return @driver.quote_subquery(subquery)
end

#quote_value(value) ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 165

def quote_value(value)

    if (value.string?) or (value.symbol?)
        result = @driver.quote_string(value.to_s)
    elsif value.kind_of? Integer
        result = @driver.quote_integer(value)
    elsif value.array?
        result = "(" << self.process_array(value) << ")"    # TODO: question is, if we should do it here, if it's enough general just for processor
    elsif value.kind_of? Float
        result = @driver.quote_float(value)
    elsif (value.kind_of? TrueClass) or (value.kind_of? FalseClass)
        result = @driver.quote_boolean(value)
    elsif (value.kind_of? Date) or (value.kind_of? DateTime)
        result = @driver.quote_date_time(value)
    elsif value.nil?
        result = @driver.null
    else
        result = value.to_s
    end
    
    return result
    
end

#replacer ⇒ Object 



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# File 'lib/fluent-query/queries/processor.rb', line 357

def replacer
    if @__fluent_replacer.nil?
        parts = Array[self.class::COLUMN_DIRECTIVE, self.class::STRING_DIRECTIVE]

        result = ""
        result << "(?:(?:" << parts.join(")|(?:") << "))"
        
        @__fluent_replacer = Regexp::new(result)
    end

    @__fluent_replacer
end