import

qemu/qobject/qdict.c

@@ -0,0 +1,699 @@
+/*
+ * QDict Module
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ *  Luiz Capitulino <lcapitulino@redhat.com>
+ *
+ * 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 "qapi/qmp/qint.h"
+#include "qapi/qmp/qfloat.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qbool.h"
+#include "qapi/qmp/qstring.h"
+#include "qapi/qmp/qobject.h"
+#include "qemu/queue.h"
+#include "qemu-common.h"
+
+static void qdict_destroy_obj(QObject *obj);
+
+static const QType qdict_type = {
+    .code = QTYPE_QDICT,
+    .destroy = qdict_destroy_obj,
+};
+
+/**
+ * qdict_new(): Create a new QDict
+ *
+ * Return strong reference.
+ */
+QDict *qdict_new(void)
+{
+    QDict *qdict;
+
+    qdict = g_malloc0(sizeof(*qdict));
+    QOBJECT_INIT(qdict, &qdict_type);
+
+    return qdict;
+}
+
+/**
+ * qobject_to_qdict(): Convert a QObject into a QDict
+ */
+QDict *qobject_to_qdict(const QObject *obj)
+{
+    if (qobject_type(obj) != QTYPE_QDICT)
+        return NULL;
+
+    return container_of(obj, QDict, base);
+}
+
+/**
+ * tdb_hash(): based on the hash agorithm from gdbm, via tdb
+ * (from module-init-tools)
+ */
+static unsigned int tdb_hash(const char *name)
+{
+    unsigned value;	/* Used to compute the hash value.  */
+    unsigned   i;	/* Used to cycle through random values. */
+
+    /* Set the initial value from the key size. */
+    for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
+        value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
+
+    return (1103515243 * value + 12345);
+}
+
+/**
+ * alloc_entry(): allocate a new QDictEntry
+ */
+static QDictEntry *alloc_entry(const char *key, QObject *value)
+{
+    QDictEntry *entry;
+
+    entry = g_malloc0(sizeof(*entry));
+    entry->key = g_strdup(key);
+    entry->value = value;
+
+    return entry;
+}
+
+/**
+ * qdict_entry_value(): Return qdict entry value
+ *
+ * Return weak reference.
+ */
+QObject *qdict_entry_value(const QDictEntry *entry)
+{
+    return entry->value;
+}
+
+/**
+ * qdict_entry_key(): Return qdict entry key
+ *
+ * Return a *pointer* to the string, it has to be duplicated before being
+ * stored.
+ */
+const char *qdict_entry_key(const QDictEntry *entry)
+{
+    return entry->key;
+}
+
+/**
+ * qdict_find(): List lookup function
+ */
+static QDictEntry *qdict_find(const QDict *qdict,
+                              const char *key, unsigned int bucket)
+{
+    QDictEntry *entry;
+
+    QLIST_FOREACH(entry, &qdict->table[bucket], next)
+        if (!strcmp(entry->key, key))
+            return entry;
+
+    return NULL;
+}
+
+/**
+ * qdict_put_obj(): Put a new QObject into the dictionary
+ *
+ * Insert the pair 'key:value' into 'qdict', if 'key' already exists
+ * its 'value' will be replaced.
+ *
+ * This is done by freeing the reference to the stored QObject and
+ * storing the new one in the same entry.
+ *
+ * NOTE: ownership of 'value' is transferred to the QDict
+ */
+void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
+{
+    unsigned int bucket;
+    QDictEntry *entry;
+
+    bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
+    entry = qdict_find(qdict, key, bucket);
+    if (entry) {
+        /* replace key's value */
+        qobject_decref(entry->value);
+        entry->value = value;
+    } else {
+        /* allocate a new entry */
+        entry = alloc_entry(key, value);
+        QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
+        qdict->size++;
+    }
+}
+
+/**
+ * qdict_get(): Lookup for a given 'key'
+ *
+ * Return a weak reference to the QObject associated with 'key' if
+ * 'key' is present in the dictionary, NULL otherwise.
+ */
+QObject *qdict_get(const QDict *qdict, const char *key)
+{
+    QDictEntry *entry;
+
+    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
+    return (entry == NULL ? NULL : entry->value);
+}
+
+/**
+ * qdict_haskey(): Check if 'key' exists
+ *
+ * Return 1 if 'key' exists in the dict, 0 otherwise
+ */
+int qdict_haskey(const QDict *qdict, const char *key)
+{
+    unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
+    return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
+}
+
+/**
+ * qdict_size(): Return the size of the dictionary
+ */
+size_t qdict_size(const QDict *qdict)
+{
+    return qdict->size;
+}
+
+/**
+ * qdict_get_obj(): Get a QObject of a specific type
+ */
+static QObject *qdict_get_obj(const QDict *qdict, const char *key,
+                              qtype_code type)
+{
+    QObject *obj;
+
+    obj = qdict_get(qdict, key);
+    assert(obj != NULL);
+    assert(qobject_type(obj) == type);
+
+    return obj;
+}
+
+/**
+ * qdict_get_double(): Get an number mapped by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QFloat or QInt object.
+ *
+ * Return number mapped by 'key'.
+ */
+double qdict_get_double(const QDict *qdict, const char *key)
+{
+    QObject *obj = qdict_get(qdict, key);
+
+    assert(obj);
+    switch (qobject_type(obj)) {
+    case QTYPE_QFLOAT:
+        return qfloat_get_double(qobject_to_qfloat(obj));
+    case QTYPE_QINT:
+        return qint_get_int(qobject_to_qint(obj));
+    default:
+        abort();
+    }
+}
+
+/**
+ * qdict_get_int(): Get an integer mapped by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QInt object.
+ *
+ * Return integer mapped by 'key'.
+ */
+int64_t qdict_get_int(const QDict *qdict, const char *key)
+{
+    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
+    return qint_get_int(qobject_to_qint(obj));
+}
+
+/**
+ * qdict_get_bool(): Get a bool mapped by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QBool object.
+ *
+ * Return bool mapped by 'key'.
+ */
+int qdict_get_bool(const QDict *qdict, const char *key)
+{
+    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QBOOL);
+    return qbool_get_int(qobject_to_qbool(obj));
+}
+
+/**
+ * qdict_get_qlist(): Get the QList mapped by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QList object.
+ *
+ * Return QList mapped by 'key'.
+ */
+QList *qdict_get_qlist(const QDict *qdict, const char *key)
+{
+    return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
+}
+
+/**
+ * qdict_get_qdict(): Get the QDict mapped by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QDict object.
+ *
+ * Return QDict mapped by 'key'.
+ */
+QDict *qdict_get_qdict(const QDict *qdict, const char *key)
+{
+    return qobject_to_qdict(qdict_get_obj(qdict, key, QTYPE_QDICT));
+}
+
+/**
+ * qdict_get_str(): Get a pointer to the stored string mapped
+ * by 'key'
+ *
+ * This function assumes that 'key' exists and it stores a
+ * QString object.
+ *
+ * Return pointer to the string mapped by 'key'.
+ */
+const char *qdict_get_str(const QDict *qdict, const char *key)
+{
+    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
+    return qstring_get_str(qobject_to_qstring(obj));
+}
+
+/**
+ * qdict_get_try_int(): Try to get integer mapped by 'key'
+ *
+ * Return integer mapped by 'key', if it is not present in
+ * the dictionary or if the stored object is not of QInt type
+ * 'def_value' will be returned.
+ */
+int64_t qdict_get_try_int(const QDict *qdict, const char *key,
+                          int64_t def_value)
+{
+    QObject *obj;
+
+    obj = qdict_get(qdict, key);
+    if (!obj || qobject_type(obj) != QTYPE_QINT)
+        return def_value;
+
+    return qint_get_int(qobject_to_qint(obj));
+}
+
+/**
+ * qdict_get_try_bool(): Try to get a bool mapped by 'key'
+ *
+ * Return bool mapped by 'key', if it is not present in the
+ * dictionary or if the stored object is not of QBool type
+ * 'def_value' will be returned.
+ */
+int qdict_get_try_bool(const QDict *qdict, const char *key, int def_value)
+{
+    QObject *obj;
+
+    obj = qdict_get(qdict, key);
+    if (!obj || qobject_type(obj) != QTYPE_QBOOL)
+        return def_value;
+
+    return qbool_get_int(qobject_to_qbool(obj));
+}
+
+/**
+ * qdict_get_try_str(): Try to get a pointer to the stored string
+ * mapped by 'key'
+ *
+ * Return a pointer to the string mapped by 'key', if it is not present
+ * in the dictionary or if the stored object is not of QString type
+ * NULL will be returned.
+ */
+const char *qdict_get_try_str(const QDict *qdict, const char *key)
+{
+    QObject *obj;
+
+    obj = qdict_get(qdict, key);
+    if (!obj || qobject_type(obj) != QTYPE_QSTRING)
+        return NULL;
+
+    return qstring_get_str(qobject_to_qstring(obj));
+}
+
+/**
+ * qdict_iter(): Iterate over all the dictionary's stored values.
+ *
+ * This function allows the user to provide an iterator, which will be
+ * called for each stored value in the dictionary.
+ */
+void qdict_iter(const QDict *qdict,
+                void (*iter)(const char *key, QObject *obj, void *opaque),
+                void *opaque)
+{
+    int i;
+    QDictEntry *entry;
+
+    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
+        QLIST_FOREACH(entry, &qdict->table[i], next)
+            iter(entry->key, entry->value, opaque);
+    }
+}
+
+static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
+{
+    int i;
+
+    for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
+        if (!QLIST_EMPTY(&qdict->table[i])) {
+            return QLIST_FIRST(&qdict->table[i]);
+        }
+    }
+
+    return NULL;
+}
+
+/**
+ * qdict_first(): Return first qdict entry for iteration.
+ */
+const QDictEntry *qdict_first(const QDict *qdict)
+{
+    return qdict_next_entry(qdict, 0);
+}
+
+/**
+ * qdict_next(): Return next qdict entry in an iteration.
+ */
+const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
+{
+    QDictEntry *ret;
+
+    ret = QLIST_NEXT(entry, next);
+    if (!ret) {
+        unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
+        ret = qdict_next_entry(qdict, bucket + 1);
+    }
+
+    return ret;
+}
+
+/**
+ * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
+ * another reference is added.
+ */
+QDict *qdict_clone_shallow(const QDict *src)
+{
+    QDict *dest;
+    QDictEntry *entry;
+    int i;
+
+    dest = qdict_new();
+
+    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
+        QLIST_FOREACH(entry, &src->table[i], next) {
+            qobject_incref(entry->value);
+            qdict_put_obj(dest, entry->key, entry->value);
+        }
+    }
+
+    return dest;
+}
+
+/**
+ * qentry_destroy(): Free all the memory allocated by a QDictEntry
+ */
+static void qentry_destroy(QDictEntry *e)
+{
+    assert(e != NULL);
+    assert(e->key != NULL);
+    assert(e->value != NULL);
+
+    qobject_decref(e->value);
+    g_free(e->key);
+    g_free(e);
+}
+
+/**
+ * qdict_del(): Delete a 'key:value' pair from the dictionary
+ *
+ * This will destroy all data allocated by this entry.
+ */
+void qdict_del(QDict *qdict, const char *key)
+{
+    QDictEntry *entry;
+
+    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
+    if (entry) {
+        QLIST_REMOVE(entry, next);
+        qentry_destroy(entry);
+        qdict->size--;
+    }
+}
+
+/**
+ * qdict_destroy_obj(): Free all the memory allocated by a QDict
+ */
+static void qdict_destroy_obj(QObject *obj)
+{
+    int i;
+    QDict *qdict;
+
+    assert(obj != NULL);
+    qdict = qobject_to_qdict(obj);
+
+    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
+        QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
+        while (entry) {
+            QDictEntry *tmp = QLIST_NEXT(entry, next);
+            QLIST_REMOVE(entry, next);
+            qentry_destroy(entry);
+            entry = tmp;
+        }
+    }
+
+    g_free(qdict);
+}
+
+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. */
+            qobject_incref(value);
+            qdict_put_obj(target, new_key, 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. */
+            qobject_incref(value);
+            qdict_put_obj(target, new_key, 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)) {
+            qobject_incref(entry->value);
+            qdict_put_obj(*dst, p, entry->value);
+            qdict_del(src, entry->key);
+        }
+        entry = next;
+    }
+}
+
+static bool qdict_has_prefixed_entries(const QDict *src, const char *start)
+{
+    const QDictEntry *entry;
+
+    for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
+        if (strstart(entry->key, start, NULL)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+/**
+ * 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);
+
+        is_subqdict = qdict_has_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_incref(subqobj);
+            qdict_del(src, indexstr);
+        }
+
+        qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
+    }
+}
+
+/**
+ * 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)) {
+            qobject_incref(entry->value);
+            qdict_put_obj(dest, entry->key, entry->value);
+            qdict_del(src, entry->key);
+        }
+
+        entry = next;
+    }
+}