qobject: Move block-specific qdict code to block-qdict.c (0bcc8e5b) · Commits · SUMMER2020 / students / proj-2021291

MAINTAINERS

+2 −0

Original line number	Diff line number	Diff line
		@@ -1369,6 +1369,8 @@ F: qemu-img*
		F: qemu-io*
		F: tests/qemu-iotests/
		F: util/qemu-progress.c
		F: qobject/block-qdict.c
		F: test/check-block-qdict.c
		T: git git://repo.or.cz/qemu/kevin.git block

		Block I/O path

qobject/Makefile.objs

+1 −0

Original line number	Diff line number	Diff line
		util-obj-y = qnull.o qnum.o qstring.o qdict.o qlist.o qbool.o qlit.o
		util-obj-y += qjson.o qobject.o json-lexer.o json-streamer.o json-parser.o
		util-obj-y += block-qdict.o

qobject/block-qdict.c

0 → 100644

+640 −0

Original line number	Diff line number	Diff line
		/*
		* Special QDict functions used by the block layer
		*
		* Copyright (c) 2013-2018 Red Hat, Inc.
		*
		* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
		* See the COPYING.LIB file in the top-level directory.
		*/

		#include "qemu/osdep.h"
		#include "block/qdict.h"
		#include "qapi/qmp/qlist.h"
		#include "qemu/cutils.h"
		#include "qapi/error.h"

		/**
		* qdict_copy_default(): If no entry mapped by 'key' exists in 'dst' yet, the
		* value of 'key' in 'src' is copied there (and the refcount increased
		* accordingly).
		*/
		void qdict_copy_default(QDict dst, QDict src, const char *key)
		{
		QObject *val;

		if (qdict_haskey(dst, key)) {
		return;
		}

		val = qdict_get(src, key);
		if (val) {
		qdict_put_obj(dst, key, qobject_ref(val));
		}
		}

		/**
		* qdict_set_default_str(): If no entry mapped by 'key' exists in 'dst' yet, a
		* new QString initialised by 'val' is put there.
		*/
		void qdict_set_default_str(QDict dst, const char key, const char *val)
		{
		if (qdict_haskey(dst, key)) {
		return;
		}

		qdict_put_str(dst, key, val);
		}

		static void qdict_flatten_qdict(QDict qdict, QDict target,
		const char *prefix);

		static void qdict_flatten_qlist(QList qlist, QDict target, const char *prefix)
		{
		QObject *value;
		const QListEntry *entry;
		char *new_key;
		int i;

		/* This function is never called with prefix == NULL, i.e., it is always
		* called from within qdict_flatten_q(list\|dict)(). Therefore, it does not
		* need to remove list entries during the iteration (the whole list will be
		* deleted eventually anyway from qdict_flatten_qdict()). */
		assert(prefix);

		entry = qlist_first(qlist);

		for (i = 0; entry; entry = qlist_next(entry), i++) {
		value = qlist_entry_obj(entry);
		new_key = g_strdup_printf("%s.%i", prefix, i);

		if (qobject_type(value) == QTYPE_QDICT) {
		qdict_flatten_qdict(qobject_to(QDict, value), target, new_key);
		} else if (qobject_type(value) == QTYPE_QLIST) {
		qdict_flatten_qlist(qobject_to(QList, value), target, new_key);
		} else {
		/* All other types are moved to the target unchanged. */
		qdict_put_obj(target, new_key, qobject_ref(value));
		}

		g_free(new_key);
		}
		}

		static void qdict_flatten_qdict(QDict qdict, QDict target, const char *prefix)
		{
		QObject *value;
		const QDictEntry entry, next;
		char *new_key;
		bool delete;

		entry = qdict_first(qdict);

		while (entry != NULL) {

		next = qdict_next(qdict, entry);
		value = qdict_entry_value(entry);
		new_key = NULL;
		delete = false;

		if (prefix) {
		new_key = g_strdup_printf("%s.%s", prefix, entry->key);
		}

		if (qobject_type(value) == QTYPE_QDICT) {
		/* Entries of QDicts are processed recursively, the QDict object
		* itself disappears. */
		qdict_flatten_qdict(qobject_to(QDict, value), target,
		new_key ? new_key : entry->key);
		delete = true;
		} else if (qobject_type(value) == QTYPE_QLIST) {
		qdict_flatten_qlist(qobject_to(QList, value), target,
		new_key ? new_key : entry->key);
		delete = true;
		} else if (prefix) {
		/* All other objects are moved to the target unchanged. */
		qdict_put_obj(target, new_key, qobject_ref(value));
		delete = true;
		}

		g_free(new_key);

		if (delete) {
		qdict_del(qdict, entry->key);

		/* Restart loop after modifying the iterated QDict */
		entry = qdict_first(qdict);
		continue;
		}

		entry = next;
		}
		}

		/**
		* qdict_flatten(): For each nested QDict with key x, all fields with key y
		* are moved to this QDict and their key is renamed to "x.y". For each nested
		* QList with key x, the field at index y is moved to this QDict with the key
		* "x.y" (i.e., the reverse of what qdict_array_split() does).
		* This operation is applied recursively for nested QDicts and QLists.
		*/
		void qdict_flatten(QDict *qdict)
		{
		qdict_flatten_qdict(qdict, qdict, NULL);
		}

		/* extract all the src QDict entries starting by start into dst */
		void qdict_extract_subqdict(QDict src, QDict dst, const char start)

		{
		const QDictEntry entry, next;
		const char *p;

		*dst = qdict_new();
		entry = qdict_first(src);

		while (entry != NULL) {
		next = qdict_next(src, entry);
		if (strstart(entry->key, start, &p)) {
		qdict_put_obj(*dst, p, qobject_ref(entry->value));
		qdict_del(src, entry->key);
		}
		entry = next;
		}
		}

		static int qdict_count_prefixed_entries(const QDict src, const char start)
		{
		const QDictEntry *entry;
		int count = 0;

		for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
		if (strstart(entry->key, start, NULL)) {
		if (count == INT_MAX) {
		return -ERANGE;
		}
		count++;
		}
		}

		return count;
		}

		/**
		* qdict_array_split(): This function moves array-like elements of a QDict into
		* a new QList. Every entry in the original QDict with a key "%u" or one
		* prefixed "%u.", where %u designates an unsigned integer starting at 0 and
		* incrementally counting up, will be moved to a new QDict at index %u in the
		* output QList with the key prefix removed, if that prefix is "%u.". If the
		* whole key is just "%u", the whole QObject will be moved unchanged without
		* creating a new QDict. The function terminates when there is no entry in the
		* QDict with a prefix directly (incrementally) following the last one; it also
		* returns if there are both entries with "%u" and "%u." for the same index %u.
		* Example: {"0.a": 42, "0.b": 23, "1.x": 0, "4.y": 1, "o.o": 7, "2": 66}
		* (or {"1.x": 0, "4.y": 1, "0.a": 42, "o.o": 7, "0.b": 23, "2": 66})
		* => [{"a": 42, "b": 23}, {"x": 0}, 66]
		* and {"4.y": 1, "o.o": 7} (remainder of the old QDict)
		*/
		void qdict_array_split(QDict src, QList *dst)
		{
		unsigned i;

		*dst = qlist_new();

		for (i = 0; i < UINT_MAX; i++) {
		QObject *subqobj;
		bool is_subqdict;
		QDict *subqdict;
		char indexstr[32], prefix[32];
		size_t snprintf_ret;

		snprintf_ret = snprintf(indexstr, 32, "%u", i);
		assert(snprintf_ret < 32);

		subqobj = qdict_get(src, indexstr);

		snprintf_ret = snprintf(prefix, 32, "%u.", i);
		assert(snprintf_ret < 32);

		/* Overflow is the same as positive non-zero results */
		is_subqdict = qdict_count_prefixed_entries(src, prefix);

		/*
		* There may be either a single subordinate object (named
		* "%u") or multiple objects (each with a key prefixed "%u."),
		* but not both.
		*/
		if (!subqobj == !is_subqdict) {
		break;
		}

		if (is_subqdict) {
		qdict_extract_subqdict(src, &subqdict, prefix);
		assert(qdict_size(subqdict) > 0);
		} else {
		qobject_ref(subqobj);
		qdict_del(src, indexstr);
		}

		qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
		}
		}

		/**
		* qdict_split_flat_key:
		* @key: the key string to split
		* @prefix: non-NULL pointer to hold extracted prefix
		* @suffix: non-NULL pointer to remaining suffix
		*
		* Given a flattened key such as 'foo.0.bar', split it into two parts
		* at the first '.' separator. Allows double dot ('..') to escape the
		* normal separator.
		*
		* e.g.
		* 'foo.0.bar' -> prefix='foo' and suffix='0.bar'
		* 'foo..0.bar' -> prefix='foo.0' and suffix='bar'
		*
		* The '..' sequence will be unescaped in the returned 'prefix'
		* string. The 'suffix' string will be left in escaped format, so it
		* can be fed back into the qdict_split_flat_key() key as the input
		* later.
		*
		* The caller is responsible for freeing the string returned in @prefix
		* using g_free().
		*/
		static void qdict_split_flat_key(const char key, char *prefix,
		const char **suffix)
		{
		const char *separator;
		size_t i, j;

		/* Find first '.' separator, but if there is a pair '..'
		* that acts as an escape, so skip over '..' */
		separator = NULL;
		do {
		if (separator) {
		separator += 2;
		} else {
		separator = key;
		}
		separator = strchr(separator, '.');
		} while (separator && separator[1] == '.');

		if (separator) {
		*prefix = g_strndup(key, separator - key);
		*suffix = separator + 1;
		} else {
		*prefix = g_strdup(key);
		*suffix = NULL;
		}

		/* Unescape the '..' sequence into '.' */
		for (i = 0, j = 0; (*prefix)[i] != '\0'; i++, j++) {
		if ((*prefix)[i] == '.') {
		assert((*prefix)[i + 1] == '.');
		i++;
		}
		(prefix)[j] = (prefix)[i];
		}
		(*prefix)[j] = '\0';
		}

		/**
		* qdict_is_list:
		* @maybe_list: dict to check if keys represent list elements.
		*
		* Determine whether all keys in @maybe_list are valid list elements.
		* If @maybe_list is non-zero in length and all the keys look like
		* valid list indexes, this will return 1. If @maybe_list is zero
		* length or all keys are non-numeric then it will return 0 to indicate
		* it is a normal qdict. If there is a mix of numeric and non-numeric
		* keys, or the list indexes are non-contiguous, an error is reported.
		*
		* Returns: 1 if a valid list, 0 if a dict, -1 on error
		*/
		static int qdict_is_list(QDict maybe_list, Error *errp)
		{
		const QDictEntry *ent;
		ssize_t len = 0;
		ssize_t max = -1;
		int is_list = -1;
		int64_t val;

		for (ent = qdict_first(maybe_list); ent != NULL;
		ent = qdict_next(maybe_list, ent)) {

		if (qemu_strtoi64(ent->key, NULL, 10, &val) == 0) {
		if (is_list == -1) {
		is_list = 1;
		} else if (!is_list) {
		error_setg(errp,
		"Cannot mix list and non-list keys");
		return -1;
		}
		len++;
		if (val > max) {
		max = val;
		}
		} else {
		if (is_list == -1) {
		is_list = 0;
		} else if (is_list) {
		error_setg(errp,
		"Cannot mix list and non-list keys");
		return -1;
		}
		}
		}

		if (is_list == -1) {
		assert(!qdict_size(maybe_list));
		is_list = 0;
		}

		/* NB this isn't a perfect check - e.g. it won't catch
		* a list containing '1', '+1', '01', '3', but that
		* does not matter - we've still proved that the
		* input is a list. It is up the caller to do a
		* stricter check if desired */
		if (len != (max + 1)) {
		error_setg(errp, "List indices are not contiguous, "
		"saw %zd elements but %zd largest index",
		len, max);
		return -1;
		}

		return is_list;
		}

		/**
		* qdict_crumple:
		* @src: the original flat dictionary (only scalar values) to crumple
		*
		* Takes a flat dictionary whose keys use '.' separator to indicate
		* nesting, and values are scalars, and crumples it into a nested
		* structure.
		*
		* To include a literal '.' in a key name, it must be escaped as '..'
		*
		* For example, an input of:
		*
		* { 'foo.0.bar': 'one', 'foo.0.wizz': '1',
		* 'foo.1.bar': 'two', 'foo.1.wizz': '2' }
		*
		* will result in an output of:
		*
		* {
		* 'foo': [
		* { 'bar': 'one', 'wizz': '1' },
		* { 'bar': 'two', 'wizz': '2' }
		* ],
		* }
		*
		* The following scenarios in the input dict will result in an
		* error being returned:
		*
		* - Any values in @src are non-scalar types
		* - If keys in @src imply that a particular level is both a
		* list and a dict. e.g., "foo.0.bar" and "foo.eek.bar".
		* - If keys in @src imply that a particular level is a list,
		* but the indices are non-contiguous. e.g. "foo.0.bar" and
		* "foo.2.bar" without any "foo.1.bar" present.
		* - If keys in @src represent list indexes, but are not in
		* the "%zu" format. e.g. "foo.+0.bar"
		*
		* Returns: either a QDict or QList for the nested data structure, or NULL
		* on error
		*/
		QObject qdict_crumple(const QDict src, Error **errp)
		{
		const QDictEntry *ent;
		QDict two_level, multi_level = NULL;
		QObject dst = NULL, child;
		size_t i;
		char *prefix = NULL;
		const char *suffix = NULL;
		int is_list;

		two_level = qdict_new();

		/* Step 1: split our totally flat dict into a two level dict */
		for (ent = qdict_first(src); ent != NULL; ent = qdict_next(src, ent)) {
		if (qobject_type(ent->value) == QTYPE_QDICT \|\|
		qobject_type(ent->value) == QTYPE_QLIST) {
		error_setg(errp, "Value %s is not a scalar",
		ent->key);
		goto error;
		}

		qdict_split_flat_key(ent->key, &prefix, &suffix);

		child = qdict_get(two_level, prefix);
		if (suffix) {
		QDict *child_dict = qobject_to(QDict, child);
		if (!child_dict) {
		if (child) {
		error_setg(errp, "Key %s prefix is already set as a scalar",
		prefix);
		goto error;
		}

		child_dict = qdict_new();
		qdict_put_obj(two_level, prefix, QOBJECT(child_dict));
		}

		qdict_put_obj(child_dict, suffix, qobject_ref(ent->value));
		} else {
		if (child) {
		error_setg(errp, "Key %s prefix is already set as a dict",
		prefix);
		goto error;
		}
		qdict_put_obj(two_level, prefix, qobject_ref(ent->value));
		}

		g_free(prefix);
		prefix = NULL;
		}

		/* Step 2: optionally process the two level dict recursively
		* into a multi-level dict */
		multi_level = qdict_new();
		for (ent = qdict_first(two_level); ent != NULL;
		ent = qdict_next(two_level, ent)) {
		QDict *dict = qobject_to(QDict, ent->value);
		if (dict) {
		child = qdict_crumple(dict, errp);
		if (!child) {
		goto error;
		}

		qdict_put_obj(multi_level, ent->key, child);
		} else {
		qdict_put_obj(multi_level, ent->key, qobject_ref(ent->value));
		}
		}
		qobject_unref(two_level);
		two_level = NULL;

		/* Step 3: detect if we need to turn our dict into list */
		is_list = qdict_is_list(multi_level, errp);
		if (is_list < 0) {
		goto error;
		}

		if (is_list) {
		dst = QOBJECT(qlist_new());

		for (i = 0; i < qdict_size(multi_level); i++) {
		char *key = g_strdup_printf("%zu", i);

		child = qdict_get(multi_level, key);
		g_free(key);

		if (!child) {
		error_setg(errp, "Missing list index %zu", i);
		goto error;
		}

		qlist_append_obj(qobject_to(QList, dst), qobject_ref(child));
		}
		qobject_unref(multi_level);
		multi_level = NULL;
		} else {
		dst = QOBJECT(multi_level);
		}

		return dst;

		error:
		g_free(prefix);
		qobject_unref(multi_level);
		qobject_unref(two_level);
		qobject_unref(dst);
		return NULL;
		}

		/**
		* qdict_array_entries(): Returns the number of direct array entries if the
		* sub-QDict of src specified by the prefix in subqdict (or src itself for
		* prefix == "") is valid as an array, i.e. the length of the created list if
		* the sub-QDict would become empty after calling qdict_array_split() on it. If
		* the array is not valid, -EINVAL is returned.
		*/
		int qdict_array_entries(QDict src, const char subqdict)
		{
		const QDictEntry *entry;
		unsigned i;
		unsigned entries = 0;
		size_t subqdict_len = strlen(subqdict);

		assert(!subqdict_len \|\| subqdict[subqdict_len - 1] == '.');

		/* qdict_array_split() loops until UINT_MAX, but as we want to return
		* negative errors, we only have a signed return value here. Any additional
		* entries will lead to -EINVAL. */
		for (i = 0; i < INT_MAX; i++) {
		QObject *subqobj;
		int subqdict_entries;
		char *prefix = g_strdup_printf("%s%u.", subqdict, i);

		subqdict_entries = qdict_count_prefixed_entries(src, prefix);

		/* Remove ending "." */
		prefix[strlen(prefix) - 1] = 0;
		subqobj = qdict_get(src, prefix);

		g_free(prefix);

		if (subqdict_entries < 0) {
		return subqdict_entries;
		}

		/* There may be either a single subordinate object (named "%u") or
		* multiple objects (each with a key prefixed "%u."), but not both. */
		if (subqobj && subqdict_entries) {
		return -EINVAL;
		} else if (!subqobj && !subqdict_entries) {
		break;
		}

		entries += subqdict_entries ? subqdict_entries : 1;
		}

		/* Consider everything handled that isn't part of the given sub-QDict */
		for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
		if (!strstart(qdict_entry_key(entry), subqdict, NULL)) {
		entries++;
		}
		}

		/* Anything left in the sub-QDict that wasn't handled? */
		if (qdict_size(src) != entries) {
		return -EINVAL;
		}

		return i;
		}

		/**
		* qdict_join(): Absorb the src QDict into the dest QDict, that is, move all
		* elements from src to dest.
		*
		* If an element from src has a key already present in dest, it will not be
		* moved unless overwrite is true.
		*
		* If overwrite is true, the conflicting values in dest will be discarded and
		* replaced by the corresponding values from src.
		*
		* Therefore, with overwrite being true, the src QDict will always be empty when
		* this function returns. If overwrite is false, the src QDict will be empty
		* iff there were no conflicts.
		*/
		void qdict_join(QDict dest, QDict src, bool overwrite)
		{
		const QDictEntry entry, next;

		entry = qdict_first(src);
		while (entry) {
		next = qdict_next(src, entry);

		if (overwrite \|\| !qdict_haskey(dest, entry->key)) {
		qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
		qdict_del(src, entry->key);
		}

		entry = next;
		}
		}

		/**
		* qdict_rename_keys(): Rename keys in qdict according to the replacements
		* specified in the array renames. The array must be terminated by an entry
		* with from = NULL.
		*
		* The renames are performed individually in the order of the array, so entries
		* may be renamed multiple times and may or may not conflict depending on the
		* order of the renames array.
		*
		* Returns true for success, false in error cases.
		*/
		bool qdict_rename_keys(QDict qdict, const QDictRenames renames, Error **errp)
		{
		QObject *qobj;

		while (renames->from) {
		if (qdict_haskey(qdict, renames->from)) {
		if (qdict_haskey(qdict, renames->to)) {
		error_setg(errp, "'%s' and its alias '%s' can't be used at the "
		"same time", renames->to, renames->from);
		return false;
		}

		qobj = qdict_get(qdict, renames->from);
		qdict_put_obj(qdict, renames->to, qobject_ref(qobj));
		qdict_del(qdict, renames->from);
		}

		renames++;
		}
		return true;
		}

qobject/qdict.c

+0 −629

File changed.

Preview size limit exceeded, changes collapsed.

tests/Makefile.include

+4 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,8 @@ SYSEMU_TARGET_LIST := $(subst -softmmu.mak,,$(notdir \

		check-unit-y = tests/check-qdict$(EXESUF)
		gcov-files-check-qdict-y = qobject/qdict.c
		check-unit-y = tests/check-block-qdict$(EXESUF)
		gcov-files-check-block-qdict-y = qobject/block-qdict.c
		check-unit-y += tests/test-char$(EXESUF)
		gcov-files-check-qdict-y = chardev/char.c
		check-unit-y += tests/check-qnum$(EXESUF)
		@@ -584,6 +586,7 @@ GENERATED_FILES += tests/test-qapi-types.h tests/test-qapi-visit.h \
		test-obj-y = tests/check-qnum.o tests/check-qstring.o tests/check-qdict.o \
		tests/check-qlist.o tests/check-qnull.o tests/check-qobject.o \
		tests/check-qjson.o tests/check-qlit.o \
		tests/check-block-qtest.o \
		tests/test-coroutine.o tests/test-string-output-visitor.o \
		tests/test-string-input-visitor.o tests/test-qobject-output-visitor.o \
		tests/test-clone-visitor.o \
		@@ -614,6 +617,7 @@ test-block-obj-y = $(block-obj-y) $(test-io-obj-y) tests/iothread.o
		tests/check-qnum$(EXESUF): tests/check-qnum.o $(test-util-obj-y)
		tests/check-qstring$(EXESUF): tests/check-qstring.o $(test-util-obj-y)
		tests/check-qdict$(EXESUF): tests/check-qdict.o $(test-util-obj-y)
		tests/check-block-qdict$(EXESUF): tests/check-block-qdict.o $(test-util-obj-y)
		tests/check-qlist$(EXESUF): tests/check-qlist.o $(test-util-obj-y)
		tests/check-qnull$(EXESUF): tests/check-qnull.o $(test-util-obj-y)
		tests/check-qobject$(EXESUF): tests/check-qobject.o $(test-util-obj-y)