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1 /*
2  * QDict data type.
3  *
4  * Copyright (C) 2009 Red Hat Inc.
5  *
6  * Authors:
7  *  Luiz Capitulino <lcapitulino@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2.  See
10  * the COPYING file in the top-level directory.
11  */
12 
13 #include "qint.h"
14 #include "qfloat.h"
15 #include "qdict.h"
16 #include "qbool.h"
17 #include "qstring.h"
18 #include "qobject.h"
19 #include "qemu-queue.h"
20 #include "qemu-common.h"
21 
22 static void qdict_destroy_obj(QObject *obj);
23 
24 static const QType qdict_type = {
25     .code = QTYPE_QDICT,
26     .destroy = qdict_destroy_obj,
27 };
28 
29 /**
30  * qdict_new(): Create a new QDict
31  *
32  * Return strong reference.
33  */
qdict_new(void)34 QDict *qdict_new(void)
35 {
36     QDict *qdict;
37 
38     qdict = qemu_mallocz(sizeof(*qdict));
39     QOBJECT_INIT(qdict, &qdict_type);
40 
41     return qdict;
42 }
43 
44 /**
45  * qobject_to_qdict(): Convert a QObject into a QDict
46  */
qobject_to_qdict(const QObject * obj)47 QDict *qobject_to_qdict(const QObject *obj)
48 {
49     if (qobject_type(obj) != QTYPE_QDICT)
50         return NULL;
51 
52     return container_of(obj, QDict, base);
53 }
54 
55 /**
56  * tdb_hash(): based on the hash agorithm from gdbm, via tdb
57  * (from module-init-tools)
58  */
tdb_hash(const char * name)59 static unsigned int tdb_hash(const char *name)
60 {
61     unsigned value;	/* Used to compute the hash value.  */
62     unsigned   i;	/* Used to cycle through random values. */
63 
64     /* Set the initial value from the key size. */
65     for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
66         value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
67 
68     return (1103515243 * value + 12345);
69 }
70 
71 /**
72  * alloc_entry(): allocate a new QDictEntry
73  */
alloc_entry(const char * key,QObject * value)74 static QDictEntry *alloc_entry(const char *key, QObject *value)
75 {
76     QDictEntry *entry;
77 
78     entry = qemu_mallocz(sizeof(*entry));
79     entry->key = qemu_strdup(key);
80     entry->value = value;
81 
82     return entry;
83 }
84 
85 /**
86  * qdict_find(): List lookup function
87  */
qdict_find(const QDict * qdict,const char * key,unsigned int hash)88 static QDictEntry *qdict_find(const QDict *qdict,
89                               const char *key, unsigned int hash)
90 {
91     QDictEntry *entry;
92 
93     QLIST_FOREACH(entry, &qdict->table[hash], next)
94         if (!strcmp(entry->key, key))
95             return entry;
96 
97     return NULL;
98 }
99 
100 /**
101  * qdict_put_obj(): Put a new QObject into the dictionary
102  *
103  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
104  * its 'value' will be replaced.
105  *
106  * This is done by freeing the reference to the stored QObject and
107  * storing the new one in the same entry.
108  *
109  * NOTE: ownership of 'value' is transferred to the QDict
110  */
qdict_put_obj(QDict * qdict,const char * key,QObject * value)111 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
112 {
113     unsigned int hash;
114     QDictEntry *entry;
115 
116     hash = tdb_hash(key) % QDICT_HASH_SIZE;
117     entry = qdict_find(qdict, key, hash);
118     if (entry) {
119         /* replace key's value */
120         qobject_decref(entry->value);
121         entry->value = value;
122     } else {
123         /* allocate a new entry */
124         entry = alloc_entry(key, value);
125         QLIST_INSERT_HEAD(&qdict->table[hash], entry, next);
126         qdict->size++;
127     }
128 }
129 
130 /**
131  * qdict_get(): Lookup for a given 'key'
132  *
133  * Return a weak reference to the QObject associated with 'key' if
134  * 'key' is present in the dictionary, NULL otherwise.
135  */
qdict_get(const QDict * qdict,const char * key)136 QObject *qdict_get(const QDict *qdict, const char *key)
137 {
138     QDictEntry *entry;
139 
140     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
141     return (entry == NULL ? NULL : entry->value);
142 }
143 
144 /**
145  * qdict_haskey(): Check if 'key' exists
146  *
147  * Return 1 if 'key' exists in the dict, 0 otherwise
148  */
qdict_haskey(const QDict * qdict,const char * key)149 int qdict_haskey(const QDict *qdict, const char *key)
150 {
151     unsigned int hash = tdb_hash(key) % QDICT_HASH_SIZE;
152     return (qdict_find(qdict, key, hash) == NULL ? 0 : 1);
153 }
154 
155 /**
156  * qdict_size(): Return the size of the dictionary
157  */
qdict_size(const QDict * qdict)158 size_t qdict_size(const QDict *qdict)
159 {
160     return qdict->size;
161 }
162 
163 /**
164  * qdict_get_obj(): Get a QObject of a specific type
165  */
qdict_get_obj(const QDict * qdict,const char * key,qtype_code type)166 static QObject *qdict_get_obj(const QDict *qdict, const char *key,
167                               qtype_code type)
168 {
169     QObject *obj;
170 
171     obj = qdict_get(qdict, key);
172     assert(obj != NULL);
173     assert(qobject_type(obj) == type);
174 
175     return obj;
176 }
177 
178 /**
179  * qdict_get_double(): Get an number mapped by 'key'
180  *
181  * This function assumes that 'key' exists and it stores a
182  * QFloat or QInt object.
183  *
184  * Return number mapped by 'key'.
185  */
qdict_get_double(const QDict * qdict,const char * key)186 double qdict_get_double(const QDict *qdict, const char *key)
187 {
188     QObject *obj = qdict_get(qdict, key);
189 
190     assert(obj);
191     switch (qobject_type(obj)) {
192     case QTYPE_QFLOAT:
193         return qfloat_get_double(qobject_to_qfloat(obj));
194     case QTYPE_QINT:
195         return qint_get_int(qobject_to_qint(obj));
196     default:
197         assert(0);
198     }
199 }
200 
201 /**
202  * qdict_get_int(): Get an integer mapped by 'key'
203  *
204  * This function assumes that 'key' exists and it stores a
205  * QInt object.
206  *
207  * Return integer mapped by 'key'.
208  */
qdict_get_int(const QDict * qdict,const char * key)209 int64_t qdict_get_int(const QDict *qdict, const char *key)
210 {
211     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
212     return qint_get_int(qobject_to_qint(obj));
213 }
214 
215 /**
216  * qdict_get_bool(): Get a bool mapped by 'key'
217  *
218  * This function assumes that 'key' exists and it stores a
219  * QBool object.
220  *
221  * Return bool mapped by 'key'.
222  */
qdict_get_bool(const QDict * qdict,const char * key)223 int qdict_get_bool(const QDict *qdict, const char *key)
224 {
225     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QBOOL);
226     return qbool_get_int(qobject_to_qbool(obj));
227 }
228 
229 /**
230  * qdict_get_qlist(): Get the QList mapped by 'key'
231  *
232  * This function assumes that 'key' exists and it stores a
233  * QList object.
234  *
235  * Return QList mapped by 'key'.
236  */
qdict_get_qlist(const QDict * qdict,const char * key)237 QList *qdict_get_qlist(const QDict *qdict, const char *key)
238 {
239     return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
240 }
241 
242 /**
243  * qdict_get_qdict(): Get the QDict mapped by 'key'
244  *
245  * This function assumes that 'key' exists and it stores a
246  * QDict object.
247  *
248  * Return QDict mapped by 'key'.
249  */
qdict_get_qdict(const QDict * qdict,const char * key)250 QDict *qdict_get_qdict(const QDict *qdict, const char *key)
251 {
252     return qobject_to_qdict(qdict_get_obj(qdict, key, QTYPE_QDICT));
253 }
254 
255 /**
256  * qdict_get_str(): Get a pointer to the stored string mapped
257  * by 'key'
258  *
259  * This function assumes that 'key' exists and it stores a
260  * QString object.
261  *
262  * Return pointer to the string mapped by 'key'.
263  */
qdict_get_str(const QDict * qdict,const char * key)264 const char *qdict_get_str(const QDict *qdict, const char *key)
265 {
266     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
267     return qstring_get_str(qobject_to_qstring(obj));
268 }
269 
270 /**
271  * qdict_get_try_int(): Try to get integer mapped by 'key'
272  *
273  * Return integer mapped by 'key', if it is not present in
274  * the dictionary or if the stored object is not of QInt type
275  * 'err_value' will be returned.
276  */
qdict_get_try_int(const QDict * qdict,const char * key,int64_t err_value)277 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
278                           int64_t err_value)
279 {
280     QObject *obj;
281 
282     obj = qdict_get(qdict, key);
283     if (!obj || qobject_type(obj) != QTYPE_QINT)
284         return err_value;
285 
286     return qint_get_int(qobject_to_qint(obj));
287 }
288 
289 /**
290  * qdict_get_try_str(): Try to get a pointer to the stored string
291  * mapped by 'key'
292  *
293  * Return a pointer to the string mapped by 'key', if it is not present
294  * in the dictionary or if the stored object is not of QString type
295  * NULL will be returned.
296  */
qdict_get_try_str(const QDict * qdict,const char * key)297 const char *qdict_get_try_str(const QDict *qdict, const char *key)
298 {
299     QObject *obj;
300 
301     obj = qdict_get(qdict, key);
302     if (!obj || qobject_type(obj) != QTYPE_QSTRING)
303         return NULL;
304 
305     return qstring_get_str(qobject_to_qstring(obj));
306 }
307 
308 /**
309  * qdict_iter(): Iterate over all the dictionary's stored values.
310  *
311  * This function allows the user to provide an iterator, which will be
312  * called for each stored value in the dictionary.
313  */
qdict_iter(const QDict * qdict,void (* iter)(const char * key,QObject * obj,void * opaque),void * opaque)314 void qdict_iter(const QDict *qdict,
315                 void (*iter)(const char *key, QObject *obj, void *opaque),
316                 void *opaque)
317 {
318     int i;
319     QDictEntry *entry;
320 
321     for (i = 0; i < QDICT_HASH_SIZE; i++) {
322         QLIST_FOREACH(entry, &qdict->table[i], next)
323             iter(entry->key, entry->value, opaque);
324     }
325 }
326 
327 /**
328  * qentry_destroy(): Free all the memory allocated by a QDictEntry
329  */
qentry_destroy(QDictEntry * e)330 static void qentry_destroy(QDictEntry *e)
331 {
332     assert(e != NULL);
333     assert(e->key != NULL);
334     assert(e->value != NULL);
335 
336     qobject_decref(e->value);
337     qemu_free(e->key);
338     qemu_free(e);
339 }
340 
341 /**
342  * qdict_del(): Delete a 'key:value' pair from the dictionary
343  *
344  * This will destroy all data allocated by this entry.
345  */
qdict_del(QDict * qdict,const char * key)346 void qdict_del(QDict *qdict, const char *key)
347 {
348     QDictEntry *entry;
349 
350     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
351     if (entry) {
352         QLIST_REMOVE(entry, next);
353         qentry_destroy(entry);
354         qdict->size--;
355     }
356 }
357 
358 /**
359  * qdict_destroy_obj(): Free all the memory allocated by a QDict
360  */
qdict_destroy_obj(QObject * obj)361 static void qdict_destroy_obj(QObject *obj)
362 {
363     int i;
364     QDict *qdict;
365 
366     assert(obj != NULL);
367     qdict = qobject_to_qdict(obj);
368 
369     for (i = 0; i < QDICT_HASH_SIZE; i++) {
370         QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
371         while (entry) {
372             QDictEntry *tmp = QLIST_NEXT(entry, next);
373             QLIST_REMOVE(entry, next);
374             qentry_destroy(entry);
375             entry = tmp;
376         }
377     }
378 
379     qemu_free(qdict);
380 }
381