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[PATCH 04/20] qobject: Use GString instead of QString to accumulate JSON
From: |
Markus Armbruster |
Subject: |
[PATCH 04/20] qobject: Use GString instead of QString to accumulate JSON |
Date: |
Fri, 11 Dec 2020 18:11:36 +0100 |
QString supports modifying its string, but it's quite limited: you can
only append. The remaining callers use it for building an initial
string, never for modifying it later.
Use of GString for building the initial string is actually more
convenient here. Change qobject_to_json() & friends to do that.
Once all such uses are replaced this way, QString can become immutable.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
include/qapi/qmp/qstring.h | 1 +
qobject/qjson.c | 85 +++++++++++++++++---------------------
qobject/qstring.c | 19 +++++++++
3 files changed, 58 insertions(+), 47 deletions(-)
diff --git a/include/qapi/qmp/qstring.h b/include/qapi/qmp/qstring.h
index e2e356e5e7..ae7698d6c7 100644
--- a/include/qapi/qmp/qstring.h
+++ b/include/qapi/qmp/qstring.h
@@ -25,6 +25,7 @@ struct QString {
QString *qstring_new(void);
QString *qstring_from_str(const char *str);
QString *qstring_from_substr(const char *str, size_t start, size_t end);
+QString *qstring_from_gstring(GString *gstr);
size_t qstring_get_length(const QString *qstring);
const char *qstring_get_str(const QString *qstring);
const char *qstring_get_try_str(const QString *qstring);
diff --git a/qobject/qjson.c b/qobject/qjson.c
index 523a4ab8de..e7100a539c 100644
--- a/qobject/qjson.c
+++ b/qobject/qjson.c
@@ -149,28 +149,23 @@ QDict *qdict_from_jsonf_nofail(const char *string, ...)
return qdict;
}
-static void json_pretty_newline(QString *str, bool pretty, int indent)
+static void json_pretty_newline(GString *accu, bool pretty, int indent)
{
- int i;
-
if (pretty) {
- qstring_append(str, "\n");
- for (i = 0; i < indent; i++) {
- qstring_append(str, " ");
- }
+ g_string_append_printf(accu, "\n%*s", indent * 4, "");
}
}
-static void to_json(const QObject *obj, QString *str, bool pretty, int indent)
+static void to_json(const QObject *obj, GString *accu, bool pretty, int indent)
{
switch (qobject_type(obj)) {
case QTYPE_QNULL:
- qstring_append(str, "null");
+ g_string_append(accu, "null");
break;
case QTYPE_QNUM: {
QNum *val = qobject_to(QNum, obj);
char *buffer = qnum_to_string(val);
- qstring_append(str, buffer);
+ g_string_append(accu, buffer);
g_free(buffer);
break;
}
@@ -178,35 +173,34 @@ static void to_json(const QObject *obj, QString *str,
bool pretty, int indent)
QString *val = qobject_to(QString, obj);
const char *ptr;
int cp;
- char buf[16];
char *end;
ptr = qstring_get_str(val);
- qstring_append(str, "\"");
+ g_string_append_c(accu, '"');
for (; *ptr; ptr = end) {
cp = mod_utf8_codepoint(ptr, 6, &end);
switch (cp) {
case '\"':
- qstring_append(str, "\\\"");
+ g_string_append(accu, "\\\"");
break;
case '\\':
- qstring_append(str, "\\\\");
+ g_string_append(accu, "\\\\");
break;
case '\b':
- qstring_append(str, "\\b");
+ g_string_append(accu, "\\b");
break;
case '\f':
- qstring_append(str, "\\f");
+ g_string_append(accu, "\\f");
break;
case '\n':
- qstring_append(str, "\\n");
+ g_string_append(accu, "\\n");
break;
case '\r':
- qstring_append(str, "\\r");
+ g_string_append(accu, "\\r");
break;
case '\t':
- qstring_append(str, "\\t");
+ g_string_append(accu, "\\t");
break;
default:
if (cp < 0) {
@@ -214,20 +208,18 @@ static void to_json(const QObject *obj, QString *str,
bool pretty, int indent)
}
if (cp > 0xFFFF) {
/* beyond BMP; need a surrogate pair */
- snprintf(buf, sizeof(buf), "\\u%04X\\u%04X",
- 0xD800 + ((cp - 0x10000) >> 10),
- 0xDC00 + ((cp - 0x10000) & 0x3FF));
+ g_string_append_printf(accu, "\\u%04X\\u%04X",
+ 0xD800 + ((cp - 0x10000) >> 10),
+ 0xDC00 + ((cp - 0x10000) & 0x3FF));
} else if (cp < 0x20 || cp >= 0x7F) {
- snprintf(buf, sizeof(buf), "\\u%04X", cp);
+ g_string_append_printf(accu, "\\u%04X", cp);
} else {
- buf[0] = cp;
- buf[1] = 0;
+ g_string_append_c(accu, cp);
}
- qstring_append(str, buf);
}
};
- qstring_append(str, "\"");
+ g_string_append_c(accu, '"');
break;
}
case QTYPE_QDICT: {
@@ -237,25 +229,25 @@ static void to_json(const QObject *obj, QString *str,
bool pretty, int indent)
const QDictEntry *entry;
QString *qkey;
- qstring_append(str, "{");
+ g_string_append_c(accu, '{');
for (entry = qdict_first(val);
entry;
entry = qdict_next(val, entry)) {
- qstring_append(str, sep);
- json_pretty_newline(str, pretty, indent + 1);
+ g_string_append(accu, sep);
+ json_pretty_newline(accu, pretty, indent + 1);
qkey = qstring_from_str(qdict_entry_key(entry));
- to_json(QOBJECT(qkey), str, pretty, indent + 1);
+ to_json(QOBJECT(qkey), accu, pretty, indent + 1);
qobject_unref(qkey);
- qstring_append(str, ": ");
- to_json(qdict_entry_value(entry), str, pretty, indent + 1);
+ g_string_append(accu, ": ");
+ to_json(qdict_entry_value(entry), accu, pretty, indent + 1);
sep = comma;
}
- json_pretty_newline(str, pretty, indent);
- qstring_append(str, "}");
+ json_pretty_newline(accu, pretty, indent);
+ g_string_append_c(accu, '}');
break;
}
case QTYPE_QLIST: {
@@ -264,26 +256,26 @@ static void to_json(const QObject *obj, QString *str,
bool pretty, int indent)
const char *sep = "";
QListEntry *entry;
- qstring_append(str, "[");
+ g_string_append_c(accu, '[');
QLIST_FOREACH_ENTRY(val, entry) {
- qstring_append(str, sep);
- json_pretty_newline(str, pretty, indent + 1);
- to_json(qlist_entry_obj(entry), str, pretty, indent + 1);
+ g_string_append(accu, sep);
+ json_pretty_newline(accu, pretty, indent + 1);
+ to_json(qlist_entry_obj(entry), accu, pretty, indent + 1);
sep = comma;
}
- json_pretty_newline(str, pretty, indent);
- qstring_append(str, "]");
+ json_pretty_newline(accu, pretty, indent);
+ g_string_append_c(accu, ']');
break;
}
case QTYPE_QBOOL: {
QBool *val = qobject_to(QBool, obj);
if (qbool_get_bool(val)) {
- qstring_append(str, "true");
+ g_string_append(accu, "true");
} else {
- qstring_append(str, "false");
+ g_string_append(accu, "false");
}
break;
}
@@ -294,11 +286,10 @@ static void to_json(const QObject *obj, QString *str,
bool pretty, int indent)
QString *qobject_to_json_pretty(const QObject *obj, bool pretty)
{
- QString *str = qstring_new();
+ GString *accu = g_string_new(NULL);
- to_json(obj, str, pretty, 0);
-
- return str;
+ to_json(obj, accu, pretty, 0);
+ return qstring_from_gstring(accu);
}
QString *qobject_to_json(const QObject *obj)
diff --git a/qobject/qstring.c b/qobject/qstring.c
index b66a2c35f2..af7c18ca73 100644
--- a/qobject/qstring.c
+++ b/qobject/qstring.c
@@ -66,6 +66,25 @@ QString *qstring_from_str(const char *str)
return qstring_from_substr(str, 0, strlen(str));
}
+/**
+ * qstring_from_gstring(): Convert a GString to a QString
+ *
+ * Return strong reference.
+ */
+
+QString *qstring_from_gstring(GString *gstr)
+{
+ QString *qstring;
+
+ qstring = g_malloc(sizeof(*qstring));
+ qobject_init(QOBJECT(qstring), QTYPE_QSTRING);
+ qstring->length = gstr->len;
+ qstring->capacity = gstr->allocated_len;
+ qstring->string = g_string_free(gstr, false);
+ return qstring;
+}
+
+
static void capacity_increase(QString *qstring, size_t len)
{
if (qstring->capacity < (qstring->length + len)) {
--
2.26.2
- [PATCH 00/20] Immutable QString, and also one JSON writer less, Markus Armbruster, 2020/12/11
- [PATCH 02/20] monitor: Use GString instead of QString for output buffer, Markus Armbruster, 2020/12/11
- [PATCH 04/20] qobject: Use GString instead of QString to accumulate JSON,
Markus Armbruster <=
- [PATCH 14/20] qobject: Factor quoted_str() out of to_json(), Markus Armbruster, 2020/12/11
- [PATCH 08/20] qobject: Move internals to qobject-internal.h, Markus Armbruster, 2020/12/11
- [PATCH 05/20] qobject: Change qobject_to_json()'s value to GString, Markus Armbruster, 2020/12/11
- [PATCH 06/20] Revert "qstring: add qstring_free()", Markus Armbruster, 2020/12/11
- [PATCH 12/20] qobject: Drop qobject_get_try_str(), Markus Armbruster, 2020/12/11
- [PATCH 19/20] block: Use GString instead of QString to build filenames, Markus Armbruster, 2020/12/11
- [PATCH 09/20] qmp: Fix tracing of non-string command IDs, Markus Armbruster, 2020/12/11
- [PATCH 03/20] qobject: Make qobject_to_json_pretty() take a pretty argument, Markus Armbruster, 2020/12/11
- [PATCH 07/20] hw/rdma: Replace QList by GQueue, Markus Armbruster, 2020/12/11