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author | Markus Armbruster <armbru@redhat.com> | 2020-12-11 18:11:47 +0100 |
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committer | Markus Armbruster <armbru@redhat.com> | 2020-12-19 10:39:16 +0100 |
commit | 998da0b1581bfda6d6d0e82b9e42edfa1bf5cfe5 (patch) | |
tree | 6b2046f40c846775fa91b1b205f61f0e277ddb15 /qobject | |
parent | 91f54d92c752e392be4903c9ad2846b2cdd0398d (diff) | |
download | qemu-998da0b1581bfda6d6d0e82b9e42edfa1bf5cfe5.zip qemu-998da0b1581bfda6d6d0e82b9e42edfa1bf5cfe5.tar.gz qemu-998da0b1581bfda6d6d0e82b9e42edfa1bf5cfe5.tar.bz2 |
qobject: Factor JSON writer out of qobject_to_json()
We have two JSON writers written in C: qobject/qjson.c provides
qobject_to_json(), and migration/qjson.c provides a more low level
imperative interface. They don't share code. The latter tacitly
limits numbers to int64_t, and strings contents to characters that
don't need escaping.
Factor out qobject_to_json()'s JSON writer as qobject/json-writer.c.
Straightforward, except for numbers: since the writer is to be
independent of QObject, it can't use qnum_to_string(). Open-code it
instead. This is actually an improvement of sorts, because it
liberates qnum_to_string() from JSON's needs: its JSON-related FIXMEs
move to the JSON writer, where they belong.
The next commit will replace migration/qjson.c.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201211171152.146877-16-armbru@redhat.com>
Diffstat (limited to 'qobject')
-rw-r--r-- | qobject/json-writer.c | 247 | ||||
-rw-r--r-- | qobject/meson.build | 5 | ||||
-rw-r--r-- | qobject/qjson.c | 123 | ||||
-rw-r--r-- | qobject/qnum.c | 5 |
4 files changed, 280 insertions, 100 deletions
diff --git a/qobject/json-writer.c b/qobject/json-writer.c new file mode 100644 index 0000000..309a31d --- /dev/null +++ b/qobject/json-writer.c @@ -0,0 +1,247 @@ +/* + * JSON Writer + * + * Copyright IBM, Corp. 2009 + * Copyright (c) 2010-2020 Red Hat Inc. + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * Markus Armbruster <armbru@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 "qemu/osdep.h" +#include "qapi/qmp/json-writer.h" +#include "qemu/unicode.h" + +struct JSONWriter { + bool pretty; + bool need_comma; + GString *contents; + GByteArray *container_is_array; +}; + +JSONWriter *json_writer_new(bool pretty) +{ + JSONWriter *writer = g_new(JSONWriter, 1); + + writer->pretty = pretty; + writer->need_comma = false; + writer->contents = g_string_new(NULL); + writer->container_is_array = g_byte_array_new(); + return writer; +} + +const char *json_writer_get(JSONWriter *writer) +{ + g_assert(!writer->container_is_array->len); + return writer->contents->str; +} + +GString *json_writer_get_and_free(JSONWriter *writer) +{ + GString *contents = writer->contents; + + writer->contents = NULL; + g_byte_array_free(writer->container_is_array, true); + g_free(writer); + return contents; +} + +void json_writer_free(JSONWriter *writer) +{ + if (writer) { + g_string_free(json_writer_get_and_free(writer), true); + } +} + +static void enter_container(JSONWriter *writer, bool is_array) +{ + unsigned depth = writer->container_is_array->len; + + g_byte_array_set_size(writer->container_is_array, depth + 1); + writer->container_is_array->data[depth] = is_array; + writer->need_comma = false; +} + +static void leave_container(JSONWriter *writer, bool is_array) +{ + unsigned depth = writer->container_is_array->len; + + assert(depth); + assert(writer->container_is_array->data[depth - 1] == is_array); + g_byte_array_set_size(writer->container_is_array, depth - 1); + writer->need_comma = true; +} + +static bool in_object(JSONWriter *writer) +{ + unsigned depth = writer->container_is_array->len; + + return depth && !writer->container_is_array->data[depth - 1]; +} + +static void pretty_newline(JSONWriter *writer) +{ + if (writer->pretty) { + g_string_append_printf(writer->contents, "\n%*s", + writer->container_is_array->len * 4, ""); + } +} + +static void pretty_newline_or_space(JSONWriter *writer) +{ + if (writer->pretty) { + g_string_append_printf(writer->contents, "\n%*s", + writer->container_is_array->len * 4, ""); + } else { + g_string_append_c(writer->contents, ' '); + } +} + +static void quoted_str(JSONWriter *writer, const char *str) +{ + const char *ptr; + char *end; + int cp; + + g_string_append_c(writer->contents, '"'); + + for (ptr = str; *ptr; ptr = end) { + cp = mod_utf8_codepoint(ptr, 6, &end); + switch (cp) { + case '\"': + g_string_append(writer->contents, "\\\""); + break; + case '\\': + g_string_append(writer->contents, "\\\\"); + break; + case '\b': + g_string_append(writer->contents, "\\b"); + break; + case '\f': + g_string_append(writer->contents, "\\f"); + break; + case '\n': + g_string_append(writer->contents, "\\n"); + break; + case '\r': + g_string_append(writer->contents, "\\r"); + break; + case '\t': + g_string_append(writer->contents, "\\t"); + break; + default: + if (cp < 0) { + cp = 0xFFFD; /* replacement character */ + } + if (cp > 0xFFFF) { + /* beyond BMP; need a surrogate pair */ + g_string_append_printf(writer->contents, "\\u%04X\\u%04X", + 0xD800 + ((cp - 0x10000) >> 10), + 0xDC00 + ((cp - 0x10000) & 0x3FF)); + } else if (cp < 0x20 || cp >= 0x7F) { + g_string_append_printf(writer->contents, "\\u%04X", cp); + } else { + g_string_append_c(writer->contents, cp); + } + } + }; + + g_string_append_c(writer->contents, '"'); +} + +static void maybe_comma_name(JSONWriter *writer, const char *name) +{ + if (writer->need_comma) { + g_string_append_c(writer->contents, ','); + pretty_newline_or_space(writer); + } else { + if (writer->contents->len) { + pretty_newline(writer); + } + writer->need_comma = true; + } + + if (in_object(writer)) { + quoted_str(writer, name); + g_string_append(writer->contents, ": "); + } +} + +void json_writer_start_object(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append_c(writer->contents, '{'); + enter_container(writer, false); +} + +void json_writer_end_object(JSONWriter *writer) +{ + leave_container(writer, false); + pretty_newline(writer); + g_string_append_c(writer->contents, '}'); +} + +void json_writer_start_array(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append_c(writer->contents, '['); + enter_container(writer, true); +} + +void json_writer_end_array(JSONWriter *writer) +{ + leave_container(writer, true); + pretty_newline(writer); + g_string_append_c(writer->contents, ']'); +} + +void json_writer_bool(JSONWriter *writer, const char *name, bool val) +{ + maybe_comma_name(writer, name); + g_string_append(writer->contents, val ? "true" : "false"); +} + +void json_writer_null(JSONWriter *writer, const char *name) +{ + maybe_comma_name(writer, name); + g_string_append(writer->contents, "null"); +} + +void json_writer_int64(JSONWriter *writer, const char *name, int64_t val) +{ + maybe_comma_name(writer, name); + g_string_append_printf(writer->contents, "%" PRId64, val); +} + +void json_writer_uint64(JSONWriter *writer, const char *name, uint64_t val) +{ + maybe_comma_name(writer, name); + g_string_append_printf(writer->contents, "%" PRIu64, val); +} + +void json_writer_double(JSONWriter *writer, const char *name, double val) +{ + maybe_comma_name(writer, name); + + /* + * FIXME: g_string_append_printf() is locale dependent; but JSON + * requires numbers to be formatted as if in the C locale. + * Dependence on C locale is a pervasive issue in QEMU. + */ + /* + * FIXME: This risks printing Inf or NaN, which are not valid + * JSON values. + */ + g_string_append_printf(writer->contents, "%.17g", val); +} + +void json_writer_str(JSONWriter *writer, const char *name, const char *str) +{ + maybe_comma_name(writer, name); + quoted_str(writer, str); +} diff --git a/qobject/meson.build b/qobject/meson.build index bb63c06..4683a85 100644 --- a/qobject/meson.build +++ b/qobject/meson.build @@ -1,3 +1,4 @@ -util_ss.add(files('qnull.c', 'qnum.c', 'qstring.c', 'qdict.c', 'qlist.c', 'qbool.c', - 'qlit.c', 'qjson.c', 'qobject.c', 'json-lexer.c', 'json-streamer.c', 'json-parser.c', +util_ss.add(files('qnull.c', 'qnum.c', 'qstring.c', 'qdict.c', + 'qlist.c', 'qbool.c', 'qlit.c', 'qjson.c', 'qobject.c', + 'json-writer.c', 'json-lexer.c', 'json-streamer.c', 'json-parser.c', 'block-qdict.c')) diff --git a/qobject/qjson.c b/qobject/qjson.c index 962214f..bcc376e 100644 --- a/qobject/qjson.c +++ b/qobject/qjson.c @@ -14,13 +14,13 @@ #include "qemu/osdep.h" #include "qapi/error.h" #include "qapi/qmp/json-parser.h" +#include "qapi/qmp/json-writer.h" #include "qapi/qmp/qjson.h" #include "qapi/qmp/qbool.h" #include "qapi/qmp/qdict.h" #include "qapi/qmp/qlist.h" #include "qapi/qmp/qnum.h" #include "qapi/qmp/qstring.h" -#include "qemu/unicode.h" typedef struct JSONParsingState { @@ -149,132 +149,69 @@ QDict *qdict_from_jsonf_nofail(const char *string, ...) return qdict; } -static void json_pretty_newline(GString *accu, bool pretty, int indent) +static void to_json(JSONWriter *writer, const char *name, + const QObject *obj) { - if (pretty) { - g_string_append_printf(accu, "\n%*s", indent * 4, ""); - } -} - -static void quoted_str(const char *str, GString *accu) -{ - const char *ptr; - int cp; - char *end; - - g_string_append_c(accu, '"'); + switch (qobject_type(obj)) { + case QTYPE_QNULL: + json_writer_null(writer, name); + break; + case QTYPE_QNUM: { + QNum *val = qobject_to(QNum, obj); - for (ptr = str; *ptr; ptr = end) { - cp = mod_utf8_codepoint(ptr, 6, &end); - switch (cp) { - case '\"': - g_string_append(accu, "\\\""); - break; - case '\\': - g_string_append(accu, "\\\\"); - break; - case '\b': - g_string_append(accu, "\\b"); - break; - case '\f': - g_string_append(accu, "\\f"); + switch (val->kind) { + case QNUM_I64: + json_writer_int64(writer, name, val->u.i64); break; - case '\n': - g_string_append(accu, "\\n"); + case QNUM_U64: + json_writer_uint64(writer, name, val->u.u64); break; - case '\r': - g_string_append(accu, "\\r"); - break; - case '\t': - g_string_append(accu, "\\t"); + case QNUM_DOUBLE: + json_writer_double(writer, name, val->u.dbl); break; default: - if (cp < 0) { - cp = 0xFFFD; /* replacement character */ - } - if (cp > 0xFFFF) { - /* beyond BMP; need a surrogate pair */ - g_string_append_printf(accu, "\\u%04X\\u%04X", - 0xD800 + ((cp - 0x10000) >> 10), - 0xDC00 + ((cp - 0x10000) & 0x3FF)); - } else if (cp < 0x20 || cp >= 0x7F) { - g_string_append_printf(accu, "\\u%04X", cp); - } else { - g_string_append_c(accu, cp); - } + abort(); } - }; - - g_string_append_c(accu, '"'); -} - -static void to_json(const QObject *obj, GString *accu, bool pretty, int indent) -{ - switch (qobject_type(obj)) { - case QTYPE_QNULL: - g_string_append(accu, "null"); - break; - case QTYPE_QNUM: { - QNum *val = qobject_to(QNum, obj); - char *buffer = qnum_to_string(val); - g_string_append(accu, buffer); - g_free(buffer); break; } case QTYPE_QSTRING: { - quoted_str(qstring_get_str(qobject_to(QString, obj)), accu); + QString *val = qobject_to(QString, obj); + + json_writer_str(writer, name, qstring_get_str(val)); break; } case QTYPE_QDICT: { QDict *val = qobject_to(QDict, obj); - const char *comma = pretty ? "," : ", "; - const char *sep = ""; const QDictEntry *entry; - g_string_append_c(accu, '{'); + json_writer_start_object(writer, name); for (entry = qdict_first(val); entry; entry = qdict_next(val, entry)) { - g_string_append(accu, sep); - json_pretty_newline(accu, pretty, indent + 1); - quoted_str(qdict_entry_key(entry), accu); - g_string_append(accu, ": "); - to_json(qdict_entry_value(entry), accu, pretty, indent + 1); - sep = comma; + to_json(writer, qdict_entry_key(entry), qdict_entry_value(entry)); } - json_pretty_newline(accu, pretty, indent); - g_string_append_c(accu, '}'); + json_writer_end_object(writer); break; } case QTYPE_QLIST: { QList *val = qobject_to(QList, obj); - const char *comma = pretty ? "," : ", "; - const char *sep = ""; QListEntry *entry; - g_string_append_c(accu, '['); + json_writer_start_array(writer, name); QLIST_FOREACH_ENTRY(val, entry) { - g_string_append(accu, sep); - json_pretty_newline(accu, pretty, indent + 1); - to_json(qlist_entry_obj(entry), accu, pretty, indent + 1); - sep = comma; + to_json(writer, NULL, qlist_entry_obj(entry)); } - json_pretty_newline(accu, pretty, indent); - g_string_append_c(accu, ']'); + json_writer_end_array(writer); break; } case QTYPE_QBOOL: { QBool *val = qobject_to(QBool, obj); - if (qbool_get_bool(val)) { - g_string_append(accu, "true"); - } else { - g_string_append(accu, "false"); - } + json_writer_bool(writer, name, qbool_get_bool(val)); break; } default: @@ -284,10 +221,10 @@ static void to_json(const QObject *obj, GString *accu, bool pretty, int indent) GString *qobject_to_json_pretty(const QObject *obj, bool pretty) { - GString *accu = g_string_new(NULL); + JSONWriter *writer = json_writer_new(pretty); - to_json(obj, accu, pretty, 0); - return accu; + to_json(writer, NULL, obj); + return json_writer_get_and_free(writer); } GString *qobject_to_json(const QObject *obj) diff --git a/qobject/qnum.c b/qobject/qnum.c index 35ba41e..5dd6693 100644 --- a/qobject/qnum.c +++ b/qobject/qnum.c @@ -168,11 +168,6 @@ char *qnum_to_string(QNum *qn) case QNUM_U64: return g_strdup_printf("%" PRIu64, qn->u.u64); case QNUM_DOUBLE: - /* FIXME: g_strdup_printf() is locale dependent; but JSON requires - * numbers to be formatted as if in the C locale. Dependence - * on C locale is a pervasive issue in QEMU. */ - /* FIXME: This risks printing Inf or NaN, which are not valid - * JSON values. */ /* 17 digits suffice for IEEE double */ return g_strdup_printf("%.17g", qn->u.dbl); } |