Implement autobuild "template" system (prototype)

Remove endless boilerplate to perform the same steps in each
package by just declaring which kind of buildsystem the package uses
using the new Autobuild: spec tag.

Autobuild macros are just regular parametric macros which can be invoked
manually from specs too, which should help with reuse and handling
complicated cases.

As such , this will only work for simple and/or "perfect" upstream projects
of course. In reality many/most packages need further tweaking, but this
can now be easily done with the new append/prepend modes of the build
scriptlets.

The implementation looks more complicated than one might expect because
we want the full spec processing to take place on these parts, rather
than just macro expansion. That covers things like the special facilities
of %prep and their side-effects, %if-conditionals, possible error
handling and so on.

Add automake upstream amhello-1.0.tar.gz as an test-case of a rather
hands-free autobuild. Pretending it's a noarch package is ugly, but
handling arch-specifity in the test-suite is uglier.

Fixes: rpm-software-management#1087

build/parsePreamble.c

@@ -820,6 +820,14 @@ static rpmRC handlePreambleTag(rpmSpec spec, Package pkg, rpmTagVal tag,
 	multiToken = 1;
 
     switch (tag) {
+    case RPMTAG_AUTOBUILD:
+	SINGLE_TOKEN_ONLY;
+	if (rpmCharCheck(spec, field,
+			ALLOWED_CHARS_NAME, ALLOWED_FIRSTCHARS_NAME))
+	{
+	    goto exit;
+	}
+	break;
     case RPMTAG_NAME:
 	SINGLE_TOKEN_ONLY;
 	if (rpmCharCheck(spec, field,
@@ -1080,6 +1088,7 @@ static struct PreambleRec_s const preambleList[] = {
     {RPMTAG_BUILDPREREQ,	0, 1, 0, LEN_AND_STR("buildprereq")},
     {RPMTAG_BUILDREQUIRES,	0, 0, 0, LEN_AND_STR("buildrequires")},
     {RPMTAG_AUTOREQPROV,	0, 0, 0, LEN_AND_STR("autoreqprov")},
+    {RPMTAG_AUTOBUILD,		0, 0, 1, LEN_AND_STR("autobuild")},
     {RPMTAG_AUTOREQ,		0, 0, 0, LEN_AND_STR("autoreq")},
     {RPMTAG_AUTOPROV,		0, 0, 0, LEN_AND_STR("autoprov")},
     {RPMTAG_DOCDIR,		0, 0, 0, LEN_AND_STR("docdir")},

build/parseSpec.c

@@ -25,6 +25,8 @@
 #define ISMACRO(s,m,len) (rstreqn((s), (m), len) && !risalpha((s)[len]))
 #define ISMACROWITHARG(s,m,len) (rstreqn((s), (m), len) && (risblank((s)[len]) || !(s)[len]))
 
+static rpmRC parseSpecParts(rpmSpec spec, const char *pattern);
+
 typedef struct OpenFileInfo {
     char * fileName;
     FILE *fp;
@@ -891,6 +893,68 @@ static int parseEmpty(rpmSpec spec, int prevParsePart)
     return res;
 }
 
+static rpmRC parseAutosect(rpmSpec spec,
+			const char *prefix, const char *section, StringBuf sb)
+{
+    rpmRC rc = RPMRC_OK;
+
+    if (sb == NULL) {
+	char *mn = rstrscat(NULL, "autobuild_", prefix, "_", section, NULL);
+	if (rpmMacroIsParametric(NULL, mn)) {
+	    char *path = NULL;
+	    FD_t fd = rpmMkTempFile(NULL, &path);
+	    if (fd) {
+		char *buf = rstrscat(NULL, "%", section, "\n",
+					   "%{", mn, "}", NULL);
+		size_t blen = strlen(buf);
+		if (Fwrite(buf, blen, 1, fd) < blen)
+		   rc = RPMRC_FAIL;
+		Fclose(fd);
+	    }
+	    if (fd == NULL || rc) {
+		rpmlog(RPMLOG_ERR, _("failed to write autobuild %%%s %s: %s\n"),
+			section, path, strerror(errno));
+	    } else {
+		rc = parseSpecParts(spec, path);
+	    }
+	    unlink(path);
+	    free(path);
+	}
+	free(mn);
+    }
+    return rc;
+}
+
+struct autosect_s {
+    const char *name;
+    StringBuf sb;
+};
+
+static rpmRC parseAutobuild(rpmSpec spec)
+{
+    rpmRC rc = RPMRC_OK;
+    char *autobuild = rpmExpand("%{?autobuild}", NULL);
+    if (*autobuild) {
+	/* XXX we should have APIs for this stuff */
+	struct autosect_s autosectList[] = {
+	    { "prep", spec->prep },
+	    { "conf", spec->conf },
+	    { "generate_depends", spec->buildrequires },
+	    { "build", spec->build },
+	    { "install", spec->install },
+	    { "check", spec->check },
+	    { "clean", spec->clean },
+	    { NULL, NULL }
+	};
+
+	for (struct autosect_s *as = autosectList; !rc && as->name; as++) {
+	    rc = parseAutosect(spec, autobuild, as->name, as->sb);
+	}
+    }
+    free(autobuild);
+    return rc;
+}
+
 static rpmSpec parseSpec(const char *specFile, rpmSpecFlags flags,
 			 const char *buildRoot, int recursing);
 
@@ -1048,6 +1112,9 @@ static rpmRC parseSpecSection(rpmSpec *specptr, int secondary)
 	}
     }
 
+    if (!secondary && parseAutobuild(spec))
+	goto errxit;
+
     /* Add arch for each package */
     addArch(spec);
 

include/rpm/rpmtag.h

@@ -386,6 +386,7 @@ typedef enum rpmTag_e {
     RPMTAG_PREUNTRANSFLAGS	= 5107, /* i */
     RPMTAG_POSTUNTRANSFLAGS	= 5108, /* i */
     RPMTAG_SYSUSERS		= 5109, /* s[] extension */
+    RPMTAG_AUTOBUILD		= 5110, /* internal */
 
     RPMTAG_FIRSTFREE_TAG	/*!< internal */
 } rpmTag;

macros.in

@@ -1349,5 +1349,14 @@ end
     end
 }
 
+# example autobuild macros for autotools
+%autobuild_autotools_prep() %autosetup -p1
+%autobuild_autotools_conf() %configure
+%autobuild_autotools_build() %make_build
+%autobuild_autotools_install()\
+%make_install\
+test -d po && %find_lang %{name} ||:
+
 # \endverbatim
 #*/
+

tests/data/SPECS/amhello.spec

@@ -0,0 +1,22 @@
+Name: amhello
+Version: 1.0
+Release: 1
+Source: %{name}-%{version}.tar.gz
+License: GPLv2
+Summary: Autotools example
+# This isn't, but to simplify test-suite
+BuildArch: noarch
+Autobuild: autotools
+
+%description
+%{summary}
+
+%build -a
+cat << EOF > README.distro
+Add some distro specific notes.
+EOF
+
+%files
+%doc README.distro
+%{_bindir}/hello
+%{_docdir}/%{name}

tests/rpmbuild.at

@@ -44,6 +44,29 @@ GPL
 [])
 RPMTEST_CLEANUP
 
+AT_SETUP([rpmbuild -b autobuild])
+AT_KEYWORDS([build])
+RPMDB_INIT
+
+# This isn't a noarch package really of course, but it simplifies things here
+runroot rpmbuild -bb \
+	--define "_prefix /usr" \
+	--define "_binaries_in_noarch_packages_terminate_build 0" \
+	--define "_docdir_fmt %%{NAME}" \
+	--quiet /data/SPECS/amhello.spec
+
+RPMTEST_CHECK([
+runroot rpm -qpl /build/RPMS/noarch/amhello-1.0-1.noarch.rpm
+],
+[0],
+[/usr/bin/hello
+/usr/share/doc/amhello
+/usr/share/doc/amhello/README
+/usr/share/doc/amhello/README.distro
+],
+[ignore])
+RPMTEST_CLEANUP
+
 AT_SETUP([rpmbuild -b steps])
 AT_KEYWORDS([build])
 RPMDB_INIT