Introduce a simple API for handling JSON data

This introduces simple API for handling JSON data. There is
an internal data structure 'virJSONValuePtr' which stores a
arbitrary nested JSON value (number, string, array, object,
nul, etc).  There are APIs for constructing/querying objects
and APIs for parsing/formatting string formatted JSON data.

This uses the YAJL library for parsing/formatting from

 http://lloyd.github.com/yajl/

* src/util/json.h, src/util/json.c: Data structures and APIs
  for representing JSON data, and parsing/formatting it
* configure.in: Add check for yajl library
* libvirt.spec.in: Add build requires for yajl
* src/Makefile.am: Add json.c/h
* src/libvirt_private.syms: Export JSON symbols to drivers

configure.in

@@ -645,6 +645,56 @@ AC_SUBST([SASL_CFLAGS])
 AC_SUBST([SASL_LIBS])
 
 
+dnl YAJL JSON library http://lloyd.github.com/yajl/
+AC_ARG_WITH([yajl],
+  [  --with-yajl         use YAJL for JSON parsing/formatting],
+  [],
+  [with_yajl=check])
+
+YAJL_CFLAGS=
+YAJL_LIBS=
+if test "x$with_yajl" != "xno"; then
+  if test "x$with_yajl" != "xyes" -a "x$with_yajl" != "xcheck"; then
+    YAJL_CFLAGS="-I$with_yajl/include"
+    YAJL_LIBS="-L$with_yajl/lib"
+  fi
+  fail=0
+  old_cppflags="$CPPFLAGS"
+  old_ldflags="$LDFLAGS"
+  CPPFLAGS="$CPPFLAGS $YAJL_CFLAGS"
+  LDFLAGS="$LDFLAGS $YAJL_LIBS"
+  AC_CHECK_HEADER([yajl/yajl_common.h],[],[
+    if test "x$with_yajl" != "xcheck" ; then
+        with_yajl=no
+    else
+        fail=1
+    fi])
+  if test "x$with_yajl" != "xno" ; then
+    AC_CHECK_LIB([yajl], [yajl_parse],[
+      YAJL_LIBS="$YAJL_LIBS -lyajl"
+      with_yajl=yes
+    ],[
+      if test "x$with_yajl" = "xcheck" ; then
+        with_yajl=no
+      else
+        fail=1
+      fi
+    ])
+  fi
+  test $fail = 1 &&
+    AC_MSG_ERROR([You must install the YAJL development package in order to compile libvirt])
+  CPPFLAGS="$old_cppflags"
+  LDFLAGS="$old_ldflags"
+  if test "x$with_yajl" = "xyes" ; then
+    AC_DEFINE_UNQUOTED([HAVE_YAJL], 1,
+      [whether YAJL is available for JSON parsing/formatting])
+  fi
+fi
+AM_CONDITIONAL([HAVE_YAJL], [test "x$with_yajl" = "xyes"])
+AC_SUBST([YAJL_CFLAGS])
+AC_SUBST([YAJL_LIBS])
+
+
 dnl PolicyKit library
 POLKIT_CFLAGS=
 POLKIT_LIBS=
@@ -1859,6 +1909,11 @@ AC_MSG_NOTICE([    sasl: $SASL_CFLAGS $SASL_LIBS])
 else
 AC_MSG_NOTICE([    sasl: no])
 fi
+if test "$with_yajl" != "no" ; then
+AC_MSG_NOTICE([    yajl: $YAJL_CFLAGS $YAJL_LIBS])
+else
+AC_MSG_NOTICE([    yajl: no])
+fi
 if test "$with_avahi" = "yes" ; then
 AC_MSG_NOTICE([   avahi: $AVAHI_CFLAGS $AVAHI_LIBS])
 else

libvirt.spec.in

@@ -60,6 +60,7 @@
 %define with_netcf         0%{!?_without_netcf:0}
 %define with_udev          0%{!?_without_udev:0}
 %define with_hal           0%{!?_without_hal:0}
+%define with_yajl          0%{!?_without_yajl:0}
 
 # Non-server/HV driver defaults which are always enabled
 %define with_python        0%{!?_without_python:1}
@@ -141,6 +142,11 @@
 %define with_hal       0%{!?_without_hal:%{server_drivers}}
 %endif
 
+# Enable yajl library for JSON mode with QEMU
+%if 0%{?fedora} >= 13 || 0%{?rhel} >= 6
+%define with_yajl     0%{!?_without_yajl:%{server_drivers}}
+%endif
+
 # Force QEMU to run as non-root
 %if 0%{?fedora} >= 12 || 0%{?rhel} >= 6
 %define qemu_user  qemu
@@ -257,6 +263,9 @@ BuildRequires: hal-devel
 BuildRequires: libudev-devel >= 145
 BuildRequires: libpciaccess-devel >= 0.10.9
 %endif
+%if %{with_yajl}
+BuildRequires: yajl-devel
+%endif
 %if %{with_avahi}
 BuildRequires: avahi-devel
 %endif
@@ -495,6 +504,10 @@ of recent versions of Linux (and other OSes).
 %define _without_udev --without-udev
 %endif
 
+%if ! %{with_yajl}
+%define _without_yajl --without-yajl
+%endif
+
 %configure %{?_without_xen} \
            %{?_without_qemu} \
            %{?_without_openvz} \
@@ -522,6 +535,7 @@ of recent versions of Linux (and other OSes).
            %{?_without_selinux} \
            %{?_without_hal} \
            %{?_without_udev} \
+           %{?_without_yajl} \
            --with-qemu-user=%{qemu_user} \
            --with-qemu-group=%{qemu_group} \
            --with-init-script=redhat \

po/POTFILES.in

@@ -50,6 +50,7 @@ src/uml/uml_driver.c
 src/util/bridge.c
 src/util/conf.c
 src/util/iptables.c
+src/util/json.c
 src/util/logging.c
 src/util/pci.c
 src/util/processinfo.c

src/Makefile.am

@@ -52,6 +52,7 @@ UTIL_SOURCES =							\
 		util/hash.c util/hash.h				\
 		util/iptables.c util/iptables.h			\
 		util/ebtables.c util/ebtables.h			\
+		util/json.c util/json.h				\
 		util/logging.c util/logging.h			\
 		util/memory.c util/memory.h			\
 		util/pci.c util/pci.h				\
@@ -284,8 +285,8 @@ noinst_LTLIBRARIES = libvirt_util.la
 libvirt_la_LIBADD = libvirt_util.la
 libvirt_util_la_SOURCES =					\
 		$(UTIL_SOURCES)
-libvirt_util_la_CFLAGS =  $(CAPNG_CFLAGS)
+libvirt_util_la_CFLAGS =  $(CAPNG_CFLAGS) $(YAJL_CFLAGS)
-libvirt_util_la_LDFLAGS =  $(CAPNG_LIBS)
+libvirt_util_la_LDFLAGS =  $(CAPNG_LIBS) $(YAJL_LIBS)
 
 
 noinst_LTLIBRARIES += libvirt_conf.la
@@ -829,12 +830,13 @@ libvirt_lxc_SOURCES =						\
 		$(NODE_INFO_SOURCES)				\
 		$(ENCRYPTION_CONF_SOURCES)			\
 		$(DOMAIN_CONF_SOURCES)
-libvirt_lxc_LDFLAGS = $(WARN_CFLAGS) $(COVERAGE_LDCFLAGS) $(CAPNG_LIBS)
+libvirt_lxc_LDFLAGS = $(WARN_CFLAGS) $(COVERAGE_LDCFLAGS) $(CAPNG_LIBS) $(YAJL_LIBS)
 libvirt_lxc_LDADD = $(LIBXML_LIBS) $(NUMACTL_LIBS) ../gnulib/lib/libgnu.la
 libvirt_lxc_CFLAGS =				\
 		$(LIBPARTED_CFLAGS)		\
 		$(NUMACTL_CFLAGS)		\
 		$(CAPNG_CFLAGS)			\
+		$(YAJL_CFLAGS)			\
 		-I@top_srcdir@/src/conf
 endif
 endif

src/libvirt_private.syms

@@ -270,6 +270,53 @@ virRegisterDeviceMonitor;
 virRegisterSecretDriver;
 
 
+# json.h
+virJSONValueFree;
+virJSONValueNewString;
+virJSONValueNewStringLen;
+virJSONValueNewNumberInt;
+virJSONValueNewNumberUint;
+virJSONValueNewNumberLong;
+virJSONValueNewNumberUlong;
+virJSONValueNewNumberDouble;
+virJSONValueNewBoolean;
+virJSONValueNewNull;
+virJSONValueNewArray;
+virJSONValueNewObject;
+virJSONValueObjectAppend;
+virJSONValueObjectAppendString;
+virJSONValueObjectAppendNumberInt;
+virJSONValueObjectAppendNumberUint;
+virJSONValueObjectAppendNumberLong;
+virJSONValueObjectAppendNumberUlong;
+virJSONValueObjectAppendNumberDouble;
+virJSONValueObjectAppendBoolean;
+virJSONValueObjectAppendNull;
+virJSONValueArrayAppend;
+virJSONValueObjectHasKey;
+virJSONValueObjectGet;
+virJSONValueArraySize;
+virJSONValueArrayGet;
+virJSONValueGetString;
+virJSONValueGetNumberInt;
+virJSONValueGetNumberUint;
+virJSONValueGetNumberLong;
+virJSONValueGetNumberUlong;
+virJSONValueGetNumberDouble;
+virJSONValueGetBoolean;
+virJSONValueIsNull;
+virJSONValueObjectGetString;
+virJSONValueObjectGetNumberInt;
+virJSONValueObjectGetNumberUint;
+virJSONValueObjectGetNumberLong;
+virJSONValueObjectGetNumberUlong;
+virJSONValueObjectGetNumberDouble;
+virJSONValueObjectGetBoolean;
+virJSONValueObjectIsNull;
+virJSONValueFromString;
+virJSONValueToString;
+
+
 # logging.h
 virLogMessage;
 virLogGetNbFilters;

src/util/json.h

@@ -0,0 +1,132 @@
+/*
+ * json.h: JSON object parsing/formatting
+ *
+ * Copyright (C) 2009 Daniel P. Berrange
+ * Copyright (C) 2009 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ */
+
+
+#ifndef __VIR_JSON_H_
+#define __VIR_JSON_H_
+
+#include "internal.h"
+
+
+enum {
+    VIR_JSON_TYPE_OBJECT,
+    VIR_JSON_TYPE_ARRAY,
+    VIR_JSON_TYPE_STRING,
+    VIR_JSON_TYPE_NUMBER,
+    VIR_JSON_TYPE_BOOLEAN,
+    VIR_JSON_TYPE_NULL,
+};
+
+typedef struct _virJSONValue virJSONValue;
+typedef virJSONValue *virJSONValuePtr;
+
+typedef struct _virJSONObject virJSONObject;
+typedef virJSONObject *virJSONObjectPtr;
+
+typedef struct _virJSONObjectPair virJSONObjectPair;
+typedef virJSONObjectPair *virJSONObjectPairPtr;
+
+typedef struct _virJSONArray virJSONArray;
+typedef virJSONArray *virJSONArrayPtr;
+
+
+struct _virJSONObjectPair {
+    char *key;
+    virJSONValuePtr value;
+};
+
+struct _virJSONObject {
+    unsigned int npairs;
+    virJSONObjectPairPtr pairs;
+};
+
+struct _virJSONArray {
+    unsigned int nvalues;
+    virJSONValuePtr *values;
+};
+
+struct _virJSONValue {
+    int type;
+
+    union {
+        virJSONObject object;
+        virJSONArray array;
+        char *string;
+        char *number; /* int/float/etc format is context defined so we can't parse it here :-( */
+        int boolean;
+    } data;
+};
+
+void virJSONValueFree(virJSONValuePtr value);
+
+virJSONValuePtr virJSONValueNewString(const char *data);
+virJSONValuePtr virJSONValueNewStringLen(const char *data, size_t length);
+virJSONValuePtr virJSONValueNewNumberInt(int data);
+virJSONValuePtr virJSONValueNewNumberUint(unsigned int data);
+virJSONValuePtr virJSONValueNewNumberLong(long long data);
+virJSONValuePtr virJSONValueNewNumberUlong(unsigned long long data);
+virJSONValuePtr virJSONValueNewNumberDouble(double data);
+virJSONValuePtr virJSONValueNewBoolean(int boolean);
+virJSONValuePtr virJSONValueNewNull(void);
+virJSONValuePtr virJSONValueNewArray(void);
+virJSONValuePtr virJSONValueNewObject(void);
+
+int virJSONValueObjectAppend(virJSONValuePtr object, const char *key, virJSONValuePtr value);
+int virJSONValueArrayAppend(virJSONValuePtr object, virJSONValuePtr value);
+
+int virJSONValueObjectHasKey(virJSONValuePtr object, const char *key);
+virJSONValuePtr virJSONValueObjectGet(virJSONValuePtr object, const char *key);
+
+int virJSONValueArraySize(virJSONValuePtr object);
+virJSONValuePtr virJSONValueArrayGet(virJSONValuePtr object, unsigned int element);
+
+char *virJSONValueGetString(virJSONValuePtr object);
+int virJSONValueGetNumberInt(virJSONValuePtr object, int *value);
+int virJSONValueGetNumberUint(virJSONValuePtr object, unsigned int *value);
+int virJSONValueGetNumberLong(virJSONValuePtr object, long long *value);
+int virJSONValueGetNumberUlong(virJSONValuePtr object, unsigned long long *value);
+int virJSONValueGetNumberDouble(virJSONValuePtr object, double *value);
+int virJSONValueGetBoolean(virJSONValuePtr object);
+int virJSONValueIsNull(virJSONValuePtr object);
+
+char *virJSONValueObjectGetString(virJSONValuePtr object, const char *key);
+int virJSONValueObjectGetNumberInt(virJSONValuePtr object, const char *key, int *value);
+int virJSONValueObjectGetNumberUint(virJSONValuePtr object, const char *key, unsigned int *value);
+int virJSONValueObjectGetNumberLong(virJSONValuePtr object, const char *key, long long *value);
+int virJSONValueObjectGetNumberUlong(virJSONValuePtr object, const char *key, unsigned long long *value);
+int virJSONValueObjectGetNumberDouble(virJSONValuePtr object, const char *key, double *value);
+int virJSONValueObjectGetBoolean(virJSONValuePtr object, const char *key);
+int virJSONValueObjectIsNull(virJSONValuePtr object, const char *key);
+
+int virJSONValueObjectAppendString(virJSONValuePtr object, const char *key, const char *value);
+int virJSONValueObjectAppendNumberInt(virJSONValuePtr object, const char *key, int number);
+int virJSONValueObjectAppendNumberUint(virJSONValuePtr object, const char *key, unsigned int number);
+int virJSONValueObjectAppendNumberLong(virJSONValuePtr object, const char *key, long long number);
+int virJSONValueObjectAppendNumberUlong(virJSONValuePtr object, const char *key, unsigned long long number);
+int virJSONValueObjectAppendNumberDouble(virJSONValuePtr object, const char *key, double number);
+int virJSONValueObjectAppendBoolean(virJSONValuePtr object, const char *key, int boolean);
+int virJSONValueObjectAppendNull(virJSONValuePtr object, const char *key);
+
+virJSONValuePtr virJSONValueFromString(const char *jsonstring);
+char *virJSONValueToString(virJSONValuePtr object);
+
+#endif /* __VIR_JSON_H_ */