general.m4

autoconf是一个产生可以自动配置源代码包

# Specify the list of programs exercised by the test suite.  Their
# versions are logged, and in the case of embedded test suite, they
# must correspond to the version of the package.  PATH should be
# already preset so the proper executable will be selected.
m4_define([AT_TESTED],
[m4_append_uniq([AT_tested], [$1], [
])])


# AT_COPYRIGHT(TEXT)
# ------------------
# Emit TEXT, a copyright notice, in the top of the test suite and in
# --version output.  Macros in TEXT are evaluated once.
m4_define([AT_COPYRIGHT],
[AS_COPYRIGHT([$1])[]dnl
m4_divert_text([VERSION_NOTICES],
[
$1])])# AT_COPYRIGHT


# AT_SETUP(DESCRIPTION)
# ---------------------
# Start a group of related tests, all to be executed in the same subshell.
# The group is testing what DESCRIPTION says.
m4_define([AT_SETUP],
[m4_ifdef([AT_keywords], [m4_undefine([AT_keywords])])
m4_ifdef([AT_capture_files], [m4_undefine([AT_capture_files])])
m4_define([AT_line], AT_LINE)
m4_define([AT_xfail], [at_xfail=no])
m4_define([AT_description], [$1])
m4_define([AT_ordinal], m4_incr(AT_ordinal))
m4_append([AT_groups_all], [ ]m4_defn([AT_ordinal]))
m4_divert_push([TESTS])dnl
  AT_ordinal ) @%:@ AT_ordinal. m4_defn([AT_line]): $1
    at_setup_line='m4_defn([AT_line])'
    at_desc='$1'
    $at_quiet $ECHO_N "m4_format([%3d: %-]m4_eval(47 - m4_qdelta([$1]))[s],
	               AT_ordinal, [[$1]])[]$ECHO_C"
m4_divert_push([TEST_SCRIPT])dnl
])


# AT_XFAIL_IF(SHELL-EXPRESSION)
# -----------------------------
# Set up the test to be expected to fail if SHELL-EXPRESSION evaluates to
# true (exitcode = 0).
m4_define([AT_XFAIL_IF],
[dnl
dnl Try to limit the amount of conditionals that we emit.
m4_case([$1],
      [], [],
      [false], [],
      [:], [m4_define([AT_xfail], [at_xfail=yes])],
      [true], [m4_define([AT_xfail], [at_xfail=yes])],
      [m4_append([AT_xfail], [
      $1 && at_xfail=yes])])])


# AT_KEYWORDS(KEYWORDS)
# ---------------------
# Declare a list of keywords associated to the current test group.
m4_define([AT_KEYWORDS],
[m4_append_uniq([AT_keywords], [$1], [ ])])


# AT_CAPTURE_FILE(FILE)
# ---------------------
# If the current test group does not behave as expected, save the contents of
# FILE in the test suite log.
m4_define([AT_CAPTURE_FILE],
[m4_append_uniq([AT_capture_files], ["$1"], [ \
])])


# AT_CLEANUP
# ----------
# Complete a group of related tests.
m4_define([AT_CLEANUP],
[m4_append([AT_help_all],
m4_defn([AT_ordinal]);m4_defn([AT_line]);m4_defn([AT_description]);m4_ifdef([AT_keywords], [m4_defn([AT_keywords])]);
)dnl
m4_divert_pop([TEST_SCRIPT])dnl Back to TESTS
    AT_xfail
    echo "#                             -*- compilation -*-" >> "$at_group_log"
    (
      echo "AT_ordinal. m4_defn([AT_line]): testing $1..."
      $at_traceon
m4_undivert([TEST_SCRIPT])dnl Insert the code here
      $at_traceoff
      $at_times_p && times >"$at_times_file"
    ) AS_MESSAGE_LOG_FD>&1 2>&1 | eval $at_tee_pipe
    at_status=`cat "$at_status_file"`
    ;;

m4_divert_pop([TESTS])dnl Back to KILL.
])# AT_CLEANUP


# AT_BANNER(TEXT)
# ---------------
# Output TEXT without any shell expansion.
m4_define([AT_BANNER],
[m4_define([AT_banner_ordinal], m4_incr(AT_banner_ordinal))
m4_append([AT_groups_all], [ banner-]m4_defn([AT_banner_ordinal]))
m4_divert_text([TESTS],
[
  banner-AT_banner_ordinal ) @%:@ Banner AT_banner_ordinal. AT_LINE
    cat <<\_ATEOF

$1

_ATEOF
    ;;
])dnl
])# AT_BANNER


# AT_DATA(FILE, CONTENTS)
# -----------------------
# Initialize an input data FILE with given CONTENTS, which should end with
# an end of line.
# This macro is not robust to active symbols in CONTENTS *on purpose*.
# If you don't want CONTENTS to be evaluated, quote it twice.
m4_define([AT_DATA],
[cat >$1 <<'_ATEOF'
$2[]_ATEOF
])


# AT_CHECK(COMMANDS, [STATUS = 0], STDOUT, STDERR,
#          [RUN-IF-FAIL], [RUN-IF-PASS])
# ------------------------------------------------
# Execute a test by performing given shell COMMANDS.  These commands
# should normally exit with STATUS, while producing expected STDOUT and
# STDERR contents.  Shell metacharacters in STDOUT and STDERR are
# _not_ processed by the shell, but are treated as string literals.
#
# STATUS, STDOUT, and STDERR are not checked if equal to `ignore'.
#
# If STDOUT is `expout', then stdout is compared to the content of the file
# `expout'.  Likewise for STDERR and `experr'.
#
# If STDOUT is `stdout', then the stdout is left in the file `stdout',
# likewise for STDERR and `stderr'.  Don't do this:
#
#    AT_CHECK([command >out])
#    # Some checks on `out'
#
# do this instead:
#
#    AT_CHECK([command], [], [stdout])
#    # Some checks on `stdout'
#
# This is an unfortunate limitation inherited from Ultrix which will not
# let you redirect several times the same FD (see the Autoconf documentation).
# If you use the `AT_CHECK([command >out])' be sure to get a test suite
# that will show spurious failures.
#
# You might wonder why not just use `ignore' and directly use stdout and
# stderr left by the test suite.  Firstly because the names of these files
# is an internal detail, and secondly, because
#
#    AT_CHECK([command], [], [ignore])
#    AT_CHECK([check stdout])
#
# will use `stdout' both in input and output: undefined behavior would
# certainly result.  That's why the test suite will save them in `at-stdout'
# and `at-stderr', and will provide you with `stdout' and `stderr'.
#
# Any line of stderr starting with leading blanks and a `+' are filtered
# out, since most shells when tracing include subshell traces in stderr.
# This may cause spurious failures when the test suite is run with `-x'.
#
m4_define([AT_CHECK],
[_AT_CHECK([$1],[$2],[$3],[$4],[$5],[$6],1)])

# AT_CHECK_NOESCAPE(COMMANDS, [STATUS = 0], STDOUT, STDERR,
#                   [RUN-IF-FAIL], [RUN-IF-PASS])
# ---------------------------------------------------------
# Like AT_CHECK, but do not AS_ESCAPE shell metacharacters in the STDOUT
# and STDERR arguments before running the comparison.
m4_define([AT_CHECK_NOESCAPE],
[_AT_CHECK([$1],[$2],[$3],[$4],[$5],[$6])])


# _AT_DECIDE_TRACEABLE(COMMANDS)
# ------------------------------
# Worker for for _AT_CHECK that expands to shell code.  If COMMANDS are safe to
# trace with `set -x', the shell code will set `at_trace_this=yes'.  Otherwise,
# the shell code will print a message stating an aspect of COMMANDS that makes
# tracing them unsafe.
#
# Tracing COMMANDS is not safe if they contain a command that spans multiple
# lines.  When the test suite user passes `-x' or `--trace', the test suite
# precedes every command with a `set -x'.  Since most tests expect a specific
# stderr, if only to confirm that it is empty, the test suite filters ^+ from
# the captured stderr before comparing with the expected stderr.  If a command
# spans multiple lines, so will its trace, but a `+' only prefixes the first
# line of that trace:
#
# $ echo 'foo
# bar'
# => stdout
# foo
# bar
# => stderr
# + foo
# bar
#
# In a subset of cases, one could filter such extended shell traces from stderr.
# Since test commands spanning several lines are rare, I chose instead to simply
# not trace COMMANDS that could yield multiple trace lines.  Distinguishing such
# COMMANDS became the task at hand.
#
# These features may cause a shell command to span multiple lines:
#
# (a) A quoted literal newline.
# Example:
#   echo foo'
#   'bar
# M4 is a hostile language for the job of parsing COMMANDS to determine whether
# each literal newline is quoted, so we simply disable tracing for all COMMANDS
# that bear literal newlines.
#
# (b) A command substitution not subject to word splitting.
# Example:
#   var=$(printf 'foo\nbar')
# Example:
#   echo "`printf 'foo\\nbar`"
# One cannot know in general the number of lines a command substitution will
# yield without executing the substituted command.  As such, we disable tracing
# for all COMMANDS containing these constructs.
#
# (c) A parameter expansion not subject to word splitting.
# Example:
#   var=foo'
#   'bar
#   echo "$var"
# Parameter expansions appear in COMMANDS with much greater frequency than do
# newlines and command substitutions, so disabling tracing for all such COMMANDS
# would much more substantially devalue `testsuite -x'.  To determine which
# parameter expansions yield multiple lines, we escape all ``', `"', and `\' in
# a copy of COMMANDS and expand that string within double quotes at runtime.  If
# the result of that expansion contains multiple lines, the test suite disables
# tracing for the command in question.
#
# This method leads the test suite to expand some parameters that the shell
# itself will never expand due to single-quotes or backslash escapes.  This is
# not a problem for `$foo' expansions, which will simply yield the empty string
# or some unrelated value.  A `${...}' expansion could actually form invalid
# shell code, however; consider `${=foo}'.  Therefore, we disable tracing for
# all COMMANDS containing `${...}'.  This affects few COMMANDS.
#
# This macro falls in a very hot path; the Autoconf test suite expands it 1640
# times as of this writing.  To give a sense of the impact of the heuristics I
# just described, the test suite preemptively disables tracing for 31 of those,
# and 268 contain parameter expansions that require runtime evaluation.  The
# balance are always safe to trace.
#
# _AT_CHECK expands COMMANDS, but the Autoconf language does not provide a way
# to safely expand arbitrary COMMANDS in an argument list, so the below tests
# examine COMMANDS unexpanded.
m4_define([_AT_DECIDE_TRACEABLE],
[dnl Utility macros.
m4_pushdef([at_lf], [
])[]dnl
dnl
dnl Examine COMMANDS for a reason to never trace COMMANDS.
m4_pushdef([at_reason],
	   m4_bmatch([$1],
	             [`.*`], [[a `...` command substitution]],
	             [\$(],  [[a $(...) command substitution]],
	             [\${],  [[a ${...} parameter expansion]],
	             at_lf,  [[an embedded newline]],
		     [[]]dnl No reason.
))dnl
dnl
m4_ifval(m4_defn([at_reason]),
[echo 'Not enabling shell tracing (command contains ]m4_defn([at_reason])[)'],
[m4_bmatch([$1], [\$],
dnl COMMANDS may contain parameter expansions; expand them at runtime.
[case "AS_ESCAPE([$1], [`"\])" in
        *'
'*) echo 'Not enabling shell tracing (command contains an embedded newline)' ;;
 *) at_trace_this=yes ;;
    esac],
dnl We know at build time that tracing COMMANDS is always safe.
[at_trace_this=yes])])[]dnl
m4_popdef([at_lf])[]dnl
m4_popdef([at_reason])])


# _AT_CHECK(COMMANDS, [STATUS = 0], STDOUT, STDERR,
#           [RUN-IF-FAIL], [RUN-IF-PASS], SHELL_ESCAPE_IO)
# ---------------------------------------------------------
# Worker for AT_CHECK & AT_CHECK_NOESCAPE.  The final SHELL-ESCAPE-IO
# argument determines whether the STDOUT & STDERR arguments will be escaped or
# not.
#
#
# Implementation Details
# ----------------------
# Ideally, we would like to run
#
#    ( $at_traceon; COMMANDS >at-stdout 2> at-stderr )
#
# but we must group COMMANDS as it is not limited to a single command, and
# then the shells will save the traces in at-stderr. So we have to filter
# them out when checking stderr, and we must send them into the test suite's
# stderr to honor -x properly. Since only the first line of the trace of a
# multiline command starts with a `+', and I know of no straightforward way to
# filter out the unadorned trace lines, we disable shell tracing entirely for
# commands that could span multiple lines.
#
# Limiting COMMANDS to a single command is not good either, since them
# the user herself would use {} or (), and then we face the same problem.
#
# But then, there is no point in running
#
#   ( $at_traceon { $1 ; } >at-stdout 2>at-stder1 )
#
# instead of the simpler
#
#  ( $at_traceon; $1 ) >at-stdout 2>at-stder1
#
m4_define([_AT_CHECK],
[$at_traceoff
echo "$at_srcdir/AT_LINE: AS_ESCAPE([$1])"
echo AT_LINE >"$at_check_line_file"

at_trace_this=
if test -n "$at_traceon"; then
    _AT_DECIDE_TRACEABLE([$1])
fi

if test -n "$at_trace_this"; then
    ( $at_traceon; $1 ) >"$at_stdout" 2>"$at_stder1"
    at_status=$?
    grep '^ *+' "$at_stder1" >&2
    grep -v '^ *+' "$at_stder1" >"$at_stderr"
else
    ( :; $1 ) >"$at_stdout" 2>"$at_stderr"
    at_status=$?
fi

at_failed=false
dnl Check stderr.
m4_case([$4],
	stderr, [echo stderr:; tee stderr <"$at_stderr"],
	ignore, [echo stderr:; cat "$at_stderr"],
	experr, [$at_diff experr "$at_stderr" || at_failed=:],
	[],     [$at_diff "$at_devnull" "$at_stderr" || at_failed=:],
	[echo >>"$at_stderr"; echo "m4_ifval([$7],[AS_ESCAPE([$4])],[$4])" | $at_diff - "$at_stderr" || at_failed=:])
dnl Check stdout.
m4_case([$3],
	stdout, [echo stdout:; tee stdout <"$at_stdout"],
	ignore, [echo stdout:; cat "$at_stdout"],
	expout, [$at_diff expout "$at_stdout" || at_failed=:],
	[],     [$at_diff "$at_devnull" "$at_stdout" || at_failed=:],
	[echo >>"$at_stdout"; echo "m4_ifval([$7],[AS_ESCAPE([$3])],[$3])" | $at_diff - "$at_stdout" || at_failed=:])
dnl Check exit val.  Don't `skip' if we are precisely checking $? = 77.
case $at_status in
m4_if([$2], [77],
    [],
    [   77) echo 77 > "$at_status_file"; exit 77;;
])dnl
m4_if([$2], [ignore],
    [   *);;],
    [   m4_default([$2], [0])) ;;
   *) echo "$at_srcdir/AT_LINE: exit code was $at_status, expected m4_default([$2], [0])"
      at_failed=:;;])
esac
AS_IF($at_failed, [$5
  m4_ifdef([AT_capture_files],
    [for file in AT_capture_files
     do echo "$file:"; sed 's/^/> /' "$file"; done])
  echo 1 > "$at_status_file"
  exit 1], [$6])
$at_traceon
])# _AT_CHECK