[daap/smartpl] Add new bison/flex parsers

.gitignore

@@ -29,6 +29,7 @@ missing
 stamp-h1
 autotools-stamp
 build-stamp
+ylwrap
 owntone.spec
 owntone.conf
 owntone.service

configure.ac

@@ -31,6 +31,15 @@ If you modify any .gperf files, you will need to install it.]])],
 		[AC_MSG_ERROR([[GNU gperf required, please install it.]])])
 	])
 
+AX_PROG_FLEX([AC_DEFINE([LEX], [flex], [flex found])],
+	[AS_IF([test ! -f "$srcdir/src/smartpl_lexer.c"],
+		[AC_MSG_ERROR([flex required, please install it])])
+	])
+AX_PROG_BISON([AC_DEFINE([YACC], [bison], [GNU bison found])],
+	[AS_IF([test ! -f "$srcdir/src/smartpl_parser.c"],
+		[AC_MSG_ERROR([GNU bison required, please install it])])
+	])
+
 dnl Enable all warnings by default.
 AM_CPPFLAGS="-Wall"
 AC_SUBST([AM_CPPFLAGS])

m4/ax_prog_bison.m4

@@ -0,0 +1,65 @@
+# ===========================================================================
+#      https://www.gnu.org/software/autoconf-archive/ax_prog_bison.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_BISON(ACTION-IF-TRUE,ACTION-IF-FALSE)
+#
+# DESCRIPTION
+#
+#   Check whether bison is the parser generator. Run ACTION-IF-TRUE if
+#   successful, ACTION-IF-FALSE otherwise
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#   Copyright (c) 2010 Diego Elio Petteno` <flameeyes@gmail.com>
+#
+#   This program is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation; either version 2 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 10
+
+AC_DEFUN([AX_PROG_BISON], [
+  AC_REQUIRE([AC_PROG_YACC])
+  AC_REQUIRE([AC_PROG_EGREP])
+
+  AC_CACHE_CHECK([if bison is the parser generator],[ax_cv_prog_bison],[
+    AS_IF([$YACC --version 2>/dev/null | $EGREP -q '^bison '],
+      [ax_cv_prog_bison=yes], [ax_cv_prog_bison=no])
+  ])
+  AS_IF([test "$ax_cv_prog_bison" = "yes"], [
+      dnl replace the yacc-compatible compiler with the real bison, as
+      dnl otherwise autoconf limits us to the POSIX yacc.
+      dnl We also change the generated filename to the old one, so that
+      dnl automake's ylwrap can deal with it.
+      YACC="${YACC% -y} -o y.tab.c"
+    ] m4_ifnblank([$1], [[$1]]),
+    m4_ifnblank([$2], [[$2]])
+  )
+])
+

m4/ax_prog_flex.m4

@@ -0,0 +1,60 @@
+# ===========================================================================
+#       https://www.gnu.org/software/autoconf-archive/ax_prog_flex.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PROG_FLEX(ACTION-IF-TRUE,ACTION-IF-FALSE)
+#
+# DESCRIPTION
+#
+#   Check whether flex is the scanner generator. Run ACTION-IF-TRUE if
+#   successful, ACTION-IF-FALSE otherwise
+#
+# LICENSE
+#
+#   Copyright (c) 2009 Francesco Salvestrini <salvestrini@users.sourceforge.net>
+#   Copyright (c) 2010 Diego Elio Petteno` <flameeyes@gmail.com>
+#
+#   This program is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation; either version 2 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 13
+
+AC_DEFUN([AX_PROG_FLEX], [
+  AC_REQUIRE([AM_PROG_LEX])
+  AC_REQUIRE([AC_PROG_EGREP])
+
+  AC_CACHE_CHECK([if flex is the lexer generator],[ax_cv_prog_flex],[
+    AS_IF([$LEX --version 2>/dev/null | $EGREP -qw '^g?flex'],
+      [ax_cv_prog_flex=yes], [ax_cv_prog_flex=no])
+  ])
+  AS_IF([test "$ax_cv_prog_flex" = "yes"],
+    m4_ifnblank([$1], [[$1]]),
+    m4_ifnblank([$2], [[$2]])
+  )
+])
+

src/.gitignore

@@ -1,5 +1,8 @@
 owntone
 
+*_lexer.[ch]
+*_parser.[ch]
+
 daap_query_hash.h
 rsp_query_hash.h
 dacp_prop_hash.h

src/Makefile.am

@@ -62,6 +62,21 @@ GPERF_FILES = \
 
 GPERF_SRC = $(GPERF_FILES:.gperf=_hash.h)
 
+LEXER_SRC  = daap_lexer.l smartpl_lexer.l
+PARSER_SRC = daap_parser.y smartpl_parser.y
+
+# This flag is given to flex and tells it to produce headers. automake's ylwrap
+# doesn't seem to rename the header like it does with the .c flex output, so
+# here we give it the final name. The "$(@:.c=.h)" uses substitution reference
+# and means 'change .c to .h in $@' (the target name, e.g. calc_lexer.c).
+AM_LFLAGS = --header-file=$(@:.c=.h)
+
+# This flag is given to Bison and tells it to produce headers. Note that
+# automake recognizes this flag too, and has special logic around it, so don't
+# change it to compound arguments (so for instance no "-dv"). I'm also not sure
+# --defines will work instead of -d.
+AM_YFLAGS = -d
+
 AM_CPPFLAGS += \
 	$(OWNTONE_CPPFLAGS) \
 	$(OWNTONE_OPTS_CPPFLAGS) \
@@ -130,16 +145,27 @@ owntone_SOURCES = main.c \
 	mxml-compat.h \
 	outputs/plist_wrap.h \
 	$(LIBWEBSOCKETS_SRC) \
-	$(GPERF_SRC) 
+	$(GPERF_SRC) \
+	$(LEXER_SRC) $(PARSER_SRC)
 
-# built by maintainers, and distributed. Clean with maintainer-clean
+# This should ensure the headers are built first. automake knows how to make
+# parser headers, but doesn't know how to do that for flex. So instead we set
+# the C files as target, as the AM_LFLAGS will make sure headers are produced.
 BUILT_SOURCES = \
-	$(GPERF_SRC)
+	$(GPERF_SRC) \
+	$(LEXER_SRC:.l=.c) $(PARSER_SRC:.y=.h)
 
+# automake doesn't know how to make lexer headers, nor does it automatically
+# include them, so need to specify them as EXTRA_DIST.
 EXTRA_DIST = \
-	$(GPERF_FILES)
+	$(GPERF_FILES) \
+	$(LEXER_SRC:.l=.h)
 
 # gperf construction rules
 %_hash.h: %.gperf
 	$(AM_V_GEN)$(GPERF) --output-file=$@ $<
 
+# Anything built by make should be cleaned by make clean, but when it comes to
+# flex/bison automake's support leaves something to be desired
+clean-local:
+	rm -f $(LEXER_SRC:.l=.[ch]) $(PARSER_SRC:.y=.[ch])

src/daap_lexer.l

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2021-2022 Espen Jürgensen <espenjurgensen@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/* =========================== BOILERPLATE SECTION ===========================*/
+
+/* This is to avoid compiler warnings about unused functions. More options are
+   noyyalloc noyyrealloc noyyfree. */
+%option noyywrap nounput noinput
+
+/* Thread safe scanner */
+%option reentrant
+
+/* To avoid symbol name conflicts with multiple lexers */
+%option prefix="daap_"
+
+/* Automake's ylwrap expexts the output to have this name */
+%option outfile="lex.yy.c"
+
+/* Makes a Bison-compatible yylex */
+%option bison-bridge
+
+%{
+#include <stdio.h>
+#include "daap_parser.h"
+
+/* Unknown why this is required despite using prefix */
+#define YYSTYPE DAAP_STYPE
+
+%}
+
+/* ========================= NON-BOILERPLATE SECTION =========================*/
+
+re_quote    '
+re_key      [[:alnum:]\.\-]+
+re_value    (\\.|[^'])+
+re_operator (!?[:@])
+
+%x IN_CRITERIA IN_CRITERIA_VALUE
+
+%%
+
+{re_quote} { BEGIN IN_CRITERIA; return DAAP_T_QUOTE; }
+
+<IN_CRITERIA>{re_key}/{re_operator} { yylval->str = strdup(yytext); return DAAP_T_KEY; }
+<IN_CRITERIA>{re_operator} { BEGIN IN_CRITERIA_VALUE; return (*yytext == '!' ? DAAP_T_NOT : DAAP_T_EQUAL); }
+<IN_CRITERIA>. { return *yytext; }
+
+<IN_CRITERIA_VALUE>\*{re_value}\*/{re_quote} { yylval->str = strdup(yytext); return DAAP_T_WILDCARD; }
+<IN_CRITERIA_VALUE>{re_value}/{re_quote} { yylval->str = strdup(yytext); return DAAP_T_VALUE; }
+<IN_CRITERIA_VALUE>{re_quote} { BEGIN INITIAL; return DAAP_T_QUOTE; }
+<IN_CRITERIA_VALUE>. { return *yytext; }
+
+"+"|" "         { return DAAP_T_AND; }
+","             { return DAAP_T_OR; }
+"\r"?"\n"       { return DAAP_T_NEWLINE; }
+.               { return *yytext; }
+
+%%
+