qemu: command: Add helper to format -object strings from JSON representation

Unlike -device, qemu uses a JSON object to add backend "objects" via the
monitor rather than the string that would be passed on the commandline.

To be able to reuse code parts that configure backends for various
devices, this patch adds a helper that will allow generating the command
line representations from the JSON property object.

src/qemu/qemu_command.c

@@ -416,6 +416,117 @@ qemuDomainSupportsNetdev(virDomainDefPtr def,
     return virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV);
 }
 
+
+static int
+qemuBuildObjectCommandLinePropsInternal(const char *key,
+                                        const virJSONValue *value,
+                                        virBufferPtr buf,
+                                        bool nested)
+{
+    virJSONValuePtr elem;
+    virBitmapPtr bitmap = NULL;
+    ssize_t pos = -1;
+    ssize_t end;
+    size_t i;
+
+    switch ((virJSONType) value->type) {
+    case VIR_JSON_TYPE_STRING:
+        virBufferAsprintf(buf, ",%s=%s", key, value->data.string);
+        break;
+
+    case VIR_JSON_TYPE_NUMBER:
+        virBufferAsprintf(buf, ",%s=%s", key, value->data.number);
+        break;
+
+    case VIR_JSON_TYPE_BOOLEAN:
+        if (value->data.boolean)
+            virBufferAsprintf(buf, ",%s=yes", key);
+        else
+            virBufferAsprintf(buf, ",%s=no", key);
+
+        break;
+
+    case VIR_JSON_TYPE_ARRAY:
+        if (nested) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("nested -object property arrays are not supported"));
+            return -1;
+        }
+
+        if (virJSONValueGetArrayAsBitmap(value, &bitmap) == 0) {
+            while ((pos = virBitmapNextSetBit(bitmap, pos)) > -1) {
+                if ((end = virBitmapNextClearBit(bitmap, pos)) < 0)
+                    end = virBitmapLastSetBit(bitmap) + 1;
+
+                if (end - 1 > pos) {
+                    virBufferAsprintf(buf, ",%s=%zd-%zd", key, pos, end - 1);
+                    pos = end;
+                } else {
+                    virBufferAsprintf(buf, ",%s=%zd", key, pos);
+                }
+            }
+        } else {
+            /* fallback, treat the array as a non-bitmap, adding the key
+             * for each member */
+            for (i = 0; i < virJSONValueArraySize(value); i++) {
+                elem = virJSONValueArrayGet((virJSONValuePtr)value, i);
+
+                /* recurse to avoid duplicating code */
+                if (qemuBuildObjectCommandLinePropsInternal(key, elem, buf,
+                                                            true) < 0)
+                    return -1;
+            }
+        }
+        break;
+
+    case VIR_JSON_TYPE_OBJECT:
+    case VIR_JSON_TYPE_NULL:
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("NULL and OBJECT JSON types can't be converted to "
+                         "commandline string"));
+        return -1;
+    }
+
+    virBitmapFree(bitmap);
+    return 0;
+}
+
+
+static int
+qemuBuildObjectCommandLineProps(const char *key,
+                                const virJSONValue *value,
+                                void *opaque)
+{
+    return qemuBuildObjectCommandLinePropsInternal(key, value, opaque, false);
+}
+
+
+char *
+qemuBuildObjectCommandlineFromJSON(const char *type,
+                                   const char *alias,
+                                   virJSONValuePtr props)
+{
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    char *ret = NULL;
+
+    virBufferAsprintf(&buf, "%s,id=%s", type, alias);
+
+    if (virJSONValueObjectForeachKeyValue(props,
+                                          qemuBuildObjectCommandLineProps,
+                                          &buf) < 0)
+        goto cleanup;
+
+    if (virBufferCheckError(&buf) < 0)
+        goto cleanup;
+
+    ret = virBufferContentAndReset(&buf);
+
+ cleanup:
+    virBufferFreeAndReset(&buf);
+    return ret;
+}
+
+
 /**
  * qemuOpenVhostNet:
  * @def: domain definition

src/qemu/qemu_command.h

@@ -69,6 +69,10 @@ struct _qemuBuildCommandLineCallbacks {
 
 extern qemuBuildCommandLineCallbacks buildCommandLineCallbacks;
 
+char *qemuBuildObjectCommandlineFromJSON(const char *type,
+                                         const char *alias,
+                                         virJSONValuePtr props);
+
 virCommandPtr qemuBuildCommandLine(virConnectPtr conn,
                                    virQEMUDriverPtr driver,
                                    virDomainDefPtr def,

tests/Makefile.am

@@ -237,7 +237,8 @@ if WITH_QEMU
 test_programs += qemuxml2argvtest qemuxml2xmltest qemuxmlnstest \
 	qemuargv2xmltest qemuhelptest domainsnapshotxml2xmltest \
 	qemumonitortest qemumonitorjsontest qemuhotplugtest \
-	qemuagenttest qemucapabilitiestest qemucaps2xmltest
+	qemuagenttest qemucapabilitiestest qemucaps2xmltest \
+	qemucommandutiltest
 endif WITH_QEMU
 
 if WITH_LXC
@@ -586,6 +587,14 @@ qemucapabilitiestest_SOURCES = \
 qemucapabilitiestest_LDADD = libqemumonitortestutils.la \
 	$(qemu_LDADDS) $(LDADDS)
 
+qemucommandutiltest_SOURCES = \
+	qemucommandutiltest.c \
+	testutils.c testutils.h \
+	testutilsqemu.c testutilsqemu.h \
+	$(NULL)
+qemucommandutiltest_LDADD = libqemumonitortestutils.la \
+	$(qemu_LDADDS) $(LDADDS)
+
 qemucaps2xmltest_SOURCES = \
 	qemucaps2xmltest.c \
 	testutils.c testutils.h \
@@ -616,7 +625,7 @@ EXTRA_DIST += qemuxml2argvtest.c qemuxml2xmltest.c qemuargv2xmltest.c \
 	qemumonitortest.c testutilsqemu.c testutilsqemu.h \
 	qemumonitorjsontest.c qemuhotplugtest.c \
 	qemuagenttest.c qemucapabilitiestest.c \
-	qemucaps2xmltest.c \
+	qemucaps2xmltest.c qemucommandutiltest.c \
 	$(QEMUMONITORTESTUTILS_SOURCES)
 endif ! WITH_QEMU
 

tests/qemucommandutiltest.c

+/*
+ * Copyright (C) 2015 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "qemu/qemu_command.h"
+#include "util/virjson.h"
+#include "testutils.h"
+#include "testutilsqemu.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+typedef struct
+{
+    const char *props;
+    const char *expectprops;
+} testQemuCommandBuildObjectFromJSONData;
+
+static int
+testQemuCommandBuildObjectFromJSON(const void *opaque)
+{
+    const testQemuCommandBuildObjectFromJSONData *data = opaque;
+    virJSONValuePtr val = NULL;
+    char *expect = NULL;
+    char *result = NULL;
+    int ret = -1;
+
+    if (!(val = virJSONValueFromString(data->props))) {
+        fprintf(stderr, "Failed to parse JSON string '%s'", data->props);
+        return -1;
+    }
+
+    if (virAsprintf(&expect, "testobject,id=testalias%s%s",
+                    data->expectprops ? "," : "",
+                    data->expectprops ? data->expectprops : "") < 0)
+        return -1;
+
+    result = qemuBuildObjectCommandlineFromJSON("testobject",
+                                                "testalias",
+                                                val);
+
+    if (STRNEQ_NULLABLE(expect, result)) {
+        fprintf(stderr, "\nFailed to create object string. "
+                "\nExpected:\n'%s'\nGot:\n'%s'",
+                NULLSTR(expect), NULLSTR(result));
+        goto cleanup;
+    }
+
+    ret = 0;
+ cleanup:
+    virJSONValueFree(val);
+    VIR_FREE(result);
+    return ret;
+}
+
+static int
+mymain(void)
+{
+    int ret = 0;
+    testQemuCommandBuildObjectFromJSONData data1;
+
+#if !WITH_YAJL
+    fputs("libvirt not compiled with yajl, skipping this test\n", stderr);
+    return EXIT_AM_SKIP;
+#endif
+
+    virtTestCounterReset("testQemuCommandBuildObjectFromJSON");
+
+#define DO_TEST_COMMAND_OBJECT_FROM_JSON(PROPS, EXPECT)             \
+    do {                                                            \
+        data1.props = PROPS;                                        \
+        data1.expectprops = EXPECT;                                 \
+        if (virtTestRun(virtTestCounterNext(),                      \
+                        testQemuCommandBuildObjectFromJSON,         \
+                        &data1) < 0)                                \
+            ret = -1;                                               \
+     } while (0)
+
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{}", NULL);
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"string\":\"qwer\"}", "string=qwer");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"number\":1234}", "number=1234");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"boolean\":true}", "boolean=yes");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"boolean\":false}", "boolean=no");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[]}", NULL);
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[0]}", "bitmap=0");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[1,3,5]}",
+                                     "bitmap=1,bitmap=3,bitmap=5");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[0,1,2,3]}", "bitmap=0-3");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[1,2,3,5]}",
+                                     "bitmap=1-3,bitmap=5");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"bitmap\":[1,2,3,5,7,8,9]}",
+                                     "bitmap=1-3,bitmap=5,bitmap=7-9");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"array\":[\"bleah\",\"qwerty\",1]}",
+                                     "array=bleah,array=qwerty,array=1");
+    DO_TEST_COMMAND_OBJECT_FROM_JSON("{\"boolean\":true,\"hyphen-name\":1234,\"some_string\":\"bleah\"}",
+                                     "boolean=yes,hyphen-name=1234,some_string=bleah");
+
+    return ret;
+
+}
+
+VIRT_TEST_MAIN(mymain)