Context¶
Classes and functions enabling the command system
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waflib.Context.
HEXVERSION
= 33559552¶ Constant updated on new releases
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waflib.Context.
WAFVERSION
= '2.0.20'¶ Constant updated on new releases
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waflib.Context.
WAFREVISION
= '668769470956da8c5b60817cb8884cd7d0f87cd4'¶ Git revision when the waf version is updated
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waflib.Context.
WAFNAME
= 'waf'¶ Application name displayed on –help
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waflib.Context.
ABI
= 20¶ Version of the build data cache file format (used in
waflib.Context.DBFILE
)
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waflib.Context.
DBFILE
= '.wafpickle-linux-50727152-20'¶ Name of the pickle file for storing the build data
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waflib.Context.
APPNAME
= 'APPNAME'¶ Default application name (used by
waf dist
)
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waflib.Context.
VERSION
= 'VERSION'¶ Default application version (used by
waf dist
)
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waflib.Context.
TOP
= 'top'¶ The variable name for the top-level directory in wscript files
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waflib.Context.
OUT
= 'out'¶ The variable name for the output directory in wscript files
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waflib.Context.
WSCRIPT_FILE
= 'wscript'¶ Name of the waf script files
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waflib.Context.
launch_dir
= ''¶ Directory from which waf has been called
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waflib.Context.
run_dir
= ''¶ Location of the wscript file to use as the entry point
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waflib.Context.
top_dir
= ''¶ Location of the project directory (top), if the project was configured
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waflib.Context.
out_dir
= ''¶ Location of the build directory (out), if the project was configured
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waflib.Context.
waf_dir
= ''¶ Directory containing the waf modules
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waflib.Context.
default_encoding
= 'UTF-8'¶ Encoding to use when reading outputs from other processes
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waflib.Context.
g_module
= None¶ Module representing the top-level wscript file (see
waflib.Context.run_dir
)
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waflib.Context.
classes
= [<class 'waflib.Configure.ConfigurationContext'>, <class 'waflib.Build.EnvContext'>, <class 'waflib.Build.StepContext'>, <class 'waflib.Build.ListContext'>, <class 'waflib.Build.CleanContext'>, <class 'waflib.Build.UninstallContext'>, <class 'waflib.Build.InstallContext'>, <class 'waflib.Build.BuildContext'>, <class 'waflib.Options.OptionsContext'>]¶ List of
waflib.Context.Context
subclasses that can be used as waf commands. The classes are added automatically by a metaclass.
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waflib.Context.
create_context
(cmd_name, *k, **kw)[source]¶ Returns a new
waflib.Context.Context
instance corresponding to the given command. Used in particular bywaflib.Scripting.run_command()
Parameters: - cmd_name (string) – command name
- k (dict) – arguments to give to the context class initializer
- k – keyword arguments to give to the context class initializer
Returns: Context object
Return type:
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class
waflib.Context.
store_context
(name, bases, dct)[source]¶ Bases:
type
Metaclass that registers command classes into the list
waflib.Context.classes
Context classes must provide an attribute ‘cmd’ representing the command name, and a function attribute ‘fun’ representing the function name that the command uses.
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class
waflib.Context.
ctx
¶ Bases:
object
Base class for all
waflib.Context.Context
classes
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class
waflib.Context.
Context
(**kw)[source]¶ Bases:
waflib.Context.ctx
Default context for waf commands, and base class for new command contexts.
Context objects are passed to top-level functions:
def foo(ctx): print(ctx.__class__.__name__) # waflib.Context.Context
Subclasses must define the class attributes ‘cmd’ and ‘fun’:
Parameters: - cmd (string) – command to execute as in
waf cmd
- fun (string) – function name to execute when the command is called
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errors
= <module 'waflib.Errors' from '/builddir/build/BUILD/waf-2.0.20/waflib/Errors.py'>¶ Shortcut to
waflib.Errors
provided for convenience
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tools
= {}¶ A module cache for wscript files; see
Context.Context.load()
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load
(tool_list, *k, **kw)[source]¶ Loads a Waf tool as a module, and try calling the function named
waflib.Context.Context.fun
from it. Atooldir
argument may be provided as a list of module paths.Parameters: tool_list (list of string or space-separated string) – list of Waf tool names to load
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execute
()[source]¶ Here, it calls the function name in the top-level wscript file. Most subclasses redefine this method to provide additional functionality.
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pre_recurse
(node)[source]¶ Method executed immediately before a folder is read by
waflib.Context.Context.recurse()
. The current script is bound as a Node object onself.cur_script
, and the current path is bound toself.path
Parameters: node ( waflib.Node.Node
) – script
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post_recurse
(node)[source]¶ Restores
self.cur_script
andself.path
right afterwaflib.Context.Context.recurse()
terminates.Parameters: node ( waflib.Node.Node
) – script
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recurse
(dirs, name=None, mandatory=True, once=True, encoding=None)[source]¶ Runs user-provided functions from the supplied list of directories. The directories can be either absolute, or relative to the directory of the wscript file
The methods
waflib.Context.Context.pre_recurse()
andwaflib.Context.Context.post_recurse()
are called immediately before and after a script has been executed.Parameters: - dirs (list of string or space-separated string) – List of directories to visit
- name (string) – Name of function to invoke from the wscript
- mandatory (bool) – whether sub wscript files are required to exist
- once (bool) – read the script file once for a particular context
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exec_command
(cmd, **kw)[source]¶ Runs an external process and returns the exit status:
def run(tsk): ret = tsk.generator.bld.exec_command('touch foo.txt') return ret
If the context has the attribute ‘log’, then captures and logs the process stderr/stdout. Unlike
waflib.Context.Context.cmd_and_log()
, this method does not return the stdout/stderr values captured.Parameters: - cmd (string or list) – command argument for subprocess.Popen
- kw (dict) – keyword arguments for subprocess.Popen. The parameters input/timeout will be passed to wait/communicate.
Returns: process exit status
Return type: integer
Raises: waflib.Errors.WafError
if an invalid executable is specified for a non-shell processRaises: waflib.Errors.WafError
in case of execution failure
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cmd_and_log
(cmd, **kw)[source]¶ Executes a process and returns stdout/stderr if the execution is successful. An exception is thrown when the exit status is non-0. In that case, both stderr and stdout will be bound to the WafError object (configuration tests):
def configure(conf): out = conf.cmd_and_log(['echo', 'hello'], output=waflib.Context.STDOUT, quiet=waflib.Context.BOTH) (out, err) = conf.cmd_and_log(['echo', 'hello'], output=waflib.Context.BOTH) (out, err) = conf.cmd_and_log(cmd, input='\n'.encode(), output=waflib.Context.STDOUT) try: conf.cmd_and_log(['which', 'someapp'], output=waflib.Context.BOTH) except Errors.WafError as e: print(e.stdout, e.stderr)
Parameters: - cmd (list or string) – args for subprocess.Popen
- kw (dict) – keyword arguments for subprocess.Popen. The parameters input/timeout will be passed to wait/communicate.
Returns: a tuple containing the contents of stdout and stderr
Return type: string
Raises: waflib.Errors.WafError
if an invalid executable is specified for a non-shell processRaises: waflib.Errors.WafError
in case of execution failure; stdout/stderr/returncode are bound to the exception object
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fatal
(msg, ex=None)[source]¶ Prints an error message in red and stops command execution; this is usually used in the configuration section:
def configure(conf): conf.fatal('a requirement is missing')
Parameters: - msg (string) – message to display
- ex (exception) – optional exception object
Raises:
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to_log
(msg)[source]¶ Logs information to the logger (if present), or to stderr. Empty messages are not printed:
def build(bld): bld.to_log('starting the build')
Provide a logger on the context class or override this method if necessary.
Parameters: msg (string) – message
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msg
(*k, **kw)[source]¶ Prints a configuration message of the form
msg: result
. The second part of the message will be in colors. The output can be disabled easly by settingin_msg
to a positive value:def configure(conf): self.in_msg = 1 conf.msg('Checking for library foo', 'ok') # no output
Parameters: - msg (string) – message to display to the user
- result (string or boolean) – result to display
- color (string) – color to use, see
waflib.Logs.colors_lst
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start_msg
(*k, **kw)[source]¶ Prints the beginning of a ‘Checking for xxx’ message. See
waflib.Context.Context.msg()
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end_msg
(*k, **kw)[source]¶ Prints the end of a ‘Checking for’ message. See
waflib.Context.Context.msg()
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load_special_tools
(var, ban=[])[source]¶ Loads third-party extensions modules for certain programming languages by trying to list certain files in the extras/ directory. This method is typically called once for a programming language group, see for example
waflib.Tools.compiler_c
Parameters: - var (string) – glob expression, for example ‘cxx_*.py’
- ban (list of string) – list of exact file names to exclude
- cmd (string) – command to execute as in
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waflib.Context.
cache_modules
= {}¶ Dictionary holding already loaded modules (wscript), indexed by their absolute path. The modules are added automatically by
waflib.Context.load_module()
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waflib.Context.
load_module
(path, encoding=None)[source]¶ Loads a wscript file as a python module. This method caches results in
waflib.Context.cache_modules
Parameters: path (string) – file path Returns: Loaded Python module Return type: module
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waflib.Context.
load_tool
(tool, tooldir=None, ctx=None, with_sys_path=True)[source]¶ Imports a Waf tool as a python module, and stores it in the dict
waflib.Context.Context.tools
Parameters: - tool (string) – Name of the tool
- tooldir (list) – List of directories to search for the tool module
- with_sys_path (boolean) – whether or not to search the regular sys.path, besides waf_dir and potentially given tooldirs