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# Include file that implements 'getEnv' and friends. Do not import it!
when not declared(os):
{.error: "This is an include file for os.nim!".}
from parseutils import skipIgnoreCase
proc c_getenv(env: cstring): cstring {.
importc: "getenv", header: "<stdlib.h>".}
proc c_putenv(env: cstring): cint {.
importc: "putenv", header: "<stdlib.h>".}
# Environment handling cannot be put into RTL, because the ``envPairs``
# iterator depends on ``environment``.
var
envComputed {.threadvar.}: bool
environment {.threadvar.}: seq[string]
when defined(windows) and not defined(nimscript):
# because we support Windows GUI applications, things get really
# messy here...
when useWinUnicode:
when defined(cpp):
proc strEnd(cstr: WideCString, c = 0'i32): WideCString {.
importcpp: "(NI16*)wcschr((const wchar_t *)#, #)", header: "<string.h>".}
else:
proc strEnd(cstr: WideCString, c = 0'i32): WideCString {.
importc: "wcschr", header: "<string.h>".}
else:
proc strEnd(cstr: cstring, c = 0'i32): cstring {.
importc: "strchr", header: "<string.h>".}
proc getEnvVarsC() =
if not envComputed:
environment = @[]
when useWinUnicode:
var
env = getEnvironmentStringsW()
e = env
if e == nil: return # an error occurred
while true:
var eend = strEnd(e)
add(environment, $e)
e = cast[WideCString](cast[ByteAddress](eend)+2)
if eend[1].int == 0: break
discard freeEnvironmentStringsW(env)
else:
var
env = getEnvironmentStringsA()
e = env
if e == nil: return # an error occurred
while true:
var eend = strEnd(e)
add(environment, $e)
e = cast[cstring](cast[ByteAddress](eend)+1)
if eend[1] == '\0': break
discard freeEnvironmentStringsA(env)
envComputed = true
else:
const
useNSGetEnviron = (defined(macosx) and not defined(ios)) or defined(nimscript)
when useNSGetEnviron:
# From the manual:
# Shared libraries and bundles don't have direct access to environ,
# which is only available to the loader ld(1) when a complete program
# is being linked.
# The environment routines can still be used, but if direct access to
# environ is needed, the _NSGetEnviron() routine, defined in
# <crt_externs.h>, can be used to retrieve the address of environ
# at runtime.
proc NSGetEnviron(): ptr cstringArray {.
importc: "_NSGetEnviron", header: "<crt_externs.h>".}
else:
var gEnv {.importc: "environ".}: cstringArray
proc getEnvVarsC() =
# retrieves the variables of char** env of C's main proc
if not envComputed:
environment = @[]
when useNSGetEnviron:
var gEnv = NSGetEnviron()[]
var i = 0
while true:
if gEnv[i] == nil: break
add environment, $gEnv[i]
inc(i)
envComputed = true
proc findEnvVar(key: string): int =
getEnvVarsC()
var temp = key & '='
for i in 0..high(environment):
when defined(windows):
if skipIgnoreCase(environment[i], temp) == len(temp): return i
else:
if startsWith(environment[i], temp): return i
return -1
proc getEnv*(key: string, default = ""): TaintedString {.tags: [ReadEnvEffect].} =
## Returns the value of the `environment variable`:idx: named `key`.
##
## If the variable does not exist, `""` is returned. To distinguish
## whether a variable exists or it's value is just `""`, call
## `existsEnv(key) proc <#existsEnv,string>`_.
##
## See also:
## * `existsEnv proc <#existsEnv,string>`_
## * `putEnv proc <#putEnv,string,string>`_
## * `envPairs iterator <#envPairs.i>`_
runnableExamples:
assert getEnv("unknownEnv") == ""
assert getEnv("unknownEnv", "doesn't exist") == "doesn't exist"
when nimvm:
discard "built into the compiler"
else:
var i = findEnvVar(key)
if i >= 0:
return TaintedString(substr(environment[i], find(environment[i], '=')+1))
else:
var env = c_getenv(key)
if env == nil: return TaintedString(default)
result = TaintedString($env)
proc existsEnv*(key: string): bool {.tags: [ReadEnvEffect].} =
## Checks whether the environment variable named `key` exists.
## Returns true if it exists, false otherwise.
##
## See also:
## * `getEnv proc <#getEnv,string,string>`_
## * `putEnv proc <#putEnv,string,string>`_
## * `envPairs iterator <#envPairs.i>`_
runnableExamples:
assert not existsEnv("unknownEnv")
when nimvm:
discard "built into the compiler"
else:
if c_getenv(key) != nil: return true
else: return findEnvVar(key) >= 0
proc putEnv*(key, val: string) {.tags: [WriteEnvEffect].} =
## Sets the value of the `environment variable`:idx: named `key` to `val`.
## If an error occurs, `OSError` is raised.
##
## See also:
## * `getEnv proc <#getEnv,string,string>`_
## * `existsEnv proc <#existsEnv,string>`_
## * `envPairs iterator <#envPairs.i>`_
# Note: by storing the string in the environment sequence,
# we guarantee that we don't free the memory before the program
# ends (this is needed for POSIX compliance). It is also needed so that
# the process itself may access its modified environment variables!
when nimvm:
discard "built into the compiler"
else:
var indx = findEnvVar(key)
if indx >= 0:
environment[indx] = key & '=' & val
else:
add environment, (key & '=' & val)
indx = high(environment)
when defined(windows) and not defined(nimscript):
when useWinUnicode:
var k = newWideCString(key)
var v = newWideCString(val)
if setEnvironmentVariableW(k, v) == 0'i32: raiseOSError(osLastError())
else:
if setEnvironmentVariableA(key, val) == 0'i32: raiseOSError(osLastError())
else:
if c_putenv(environment[indx]) != 0'i32:
raiseOSError(osLastError())
iterator envPairs*(): tuple[key, value: TaintedString] {.tags: [ReadEnvEffect].} =
## Iterate over all `environments variables`:idx:.
##
## In the first component of the tuple is the name of the current variable stored,
## in the second its value.
##
## See also:
## * `getEnv proc <#getEnv,string,string>`_
## * `existsEnv proc <#existsEnv,string>`_
## * `putEnv proc <#putEnv,string,string>`_
getEnvVarsC()
for i in 0..high(environment):
var p = find(environment[i], '=')
yield (TaintedString(substr(environment[i], 0, p-1)),
TaintedString(substr(environment[i], p+1)))
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