The Availability class is concerned with libraries, headers, and functions. It can be easily wrapped (see Mkrf::Generator for an example) and should be able to be used as a basis for a variety of programs which need to determine functionality based on what libraries are available on the current system.
These really shouldn't be static like this..
Create a new Availability instance.
Valid keys for the options hash include:
:loaded_libs -- libraries to load by default
:library_paths -- libraries paths to include by default
:headers -- headers to load by default
:compiler -- which compiler to use when determining availability
:includes -- directories that should be searched for include files
# File lib/mkrf/availability.rb, line 37 def initialize(options = {}) @loaded_libs = [(options[:loaded_libs] || Config::CONFIG["LIBS"].gsub('-l', '').split)].flatten @library_paths = [(options[:library_paths] || [])].flatten # Not sure what COMMON_HEADERS looks like when populated @headers = options[:headers] || [] # Config::CONFIG["COMMON_HEADERS"] @compiler = options[:compiler] || Config::CONFIG["CC"] @includes = [(options[:includes] || DEFAULT_INCLUDES)].flatten @logger = Logger.new('mkrf.log') @defines = [] end
Returns the result of an attempt to compile and link the function body passed in
# File lib/mkrf/availability.rb, line 126 def can_link?(function_body) silence_command_line do create_source(function_body) system(link_command) end ensure FileUtils.rm_f TEMP_SOURCE_FILE FileUtils.rm_f TEMP_EXECUTABLE end
Takes the name of an executable and an optional set of paths to search. If no paths are given, the environmental path is used by default. Returns the absolute path to an executable, or nil if not found.
# File lib/mkrf/availability.rb, line 190 def find_executable(bin, *paths) paths = ENV['PATH'].split(File::PATH_SEPARATOR) if paths.empty? paths.each do |path| file = File.join(path, bin) return file if File.executable?(file) end return nil end
Returns true if the function is able to be called based on libraries and headers currently loaded. Returns false otherwise.
Params:
function -- the function to check for
# File lib/mkrf/availability.rb, line 114 def has_function?(function) if can_link?(simple_call(function)) or can_link?(simple_reference(function)) logger.info "Function found: #{function}()" return true else logger.warn "Function not found: #{function}()" return false end end
Returns true if the header is found in the default search path or in optional paths passed as an argument, false otherwise. If the header is found, the preprocessor constant HAVE_BLAH is defined where BLAH is the name of the header in uppercase without the file extension.
Params:
header -- the header to be searched for
paths -- an optional list of search paths if the header is not found in the default paths
# File lib/mkrf/availability.rb, line 98 def has_header?(header, *paths) if header_already_loaded?(header) || header_can_link?(header) || header_found_in_paths?(header, paths) defines << format("HAVE_%s", header.tr("a-z./\0055", "A-Z___")) return true end logger.warn "Header not found: #{header}" return false end
Returns a boolean whether indicating whether the library can be found by attempting to reference the function passed (main by default).
Params:
library -- the library to be included as a string
function -- a method to base the inclusion of the library on. main by default.
paths -- an optional list of search paths if the library is not found in the default paths
# File lib/mkrf/availability.rb, line 81 def has_library?(library, function = "main", *paths) logger.info "Checking for library: #{library}" return true if library_already_loaded?(library) return true if RUBY_PLATFORM =~ /mswin/ # TODO: find a way on windows # Should this be only found_library? or a specialized version with # path searching? found_library?(library, function) end
Include a header in the list of availiable headers. Returns false if the header is not available. Returns non-false otherwise. If the header is found, the preprocessor constant HAVE_BLAH is defined where BLAH is the name of the header in uppercase without the file extension.
Params:
header -- the name of the header to be included as a string.
paths -- an optional list of search paths if the header is not found in the default paths.
# File lib/mkrf/availability.rb, line 70 def include_header(header, *paths) @headers << header if has_header?(header, *paths) end
Include a library in the list of available libs. Returns false if the library is not available. Returns non-false otherwise.
Params:
library -- the library to be included as a string.
function -- a method to base the inclusion of the library on. main by default.
paths -- an optional list of search paths if the library is not found in the default paths.
# File lib/mkrf/availability.rb, line 55 def include_library(library, function = "main", *paths) paths.each do |library_dir| @library_paths << library_dir end @loaded_libs << library if has_library?(library, function) end
Returns a string of include directories formatted for compilation
# File lib/mkrf/availability.rb, line 183 def includes_compile_string @includes.collect {|i| "-I#{i}"}.join(' ') end
Returns a string of libraries formatted for compilation
# File lib/mkrf/availability.rb, line 149 def library_compile_string if RUBY_PLATFORM =~ /mswin/ @loaded_libs.join(' ') else @loaded_libs.collect {|l| "-l#{l}"}.join(' ') end end
Returns a string of libraries directories formatted for compilation
# File lib/mkrf/availability.rb, line 158 def library_paths_compile_string if RUBY_PLATFORM =~ /mswin/ @library_paths.collect {|l| "/libpath:#{l}"}.join(' ') else @library_paths.collect {|l| "-L#{l}"}.join(' ') end end
# File lib/mkrf/availability.rb, line 136 def with_headers(*args, &b) with_stackable_attribute('headers', *args, &b) end
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