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From: Ian Rogers <irogers@google.com>
To: Weilin Wang <weilin.wang@intel.com>,
	Perry Taylor <perry.taylor@intel.com>,
	Caleb Biggers <caleb.biggers@intel.com>,
	Leo Yan <leo.yan@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Sandipan Das <sandipan.das@amd.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	Zhengjun Xing <zhengjun.xing@linux.intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Ravi Bangoria <ravi.bangoria@amd.com>,
	Xin Gao <gaoxin@cdjrlc.com>, Rob Herring <robh@kernel.org>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>, Ian Rogers <irogers@google.com>
Subject: [PATCH v2 2/3] perf list: Json escape encoding improvements
Date: Thu, 17 Nov 2022 18:46:06 -0800	[thread overview]
Message-ID: <20221118024607.409083-3-irogers@google.com> (raw)
In-Reply-To: <20221118024607.409083-1-irogers@google.com>

Use strbuf to make the string under construction's length
unlimited. Use the format %s to mean a literal string copy and %S to
signify a need to escape the string. Add supported for escaping a
newline character.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-list.c | 109 +++++++++++++++++++++++---------------
 1 file changed, 67 insertions(+), 42 deletions(-)

diff --git a/tools/perf/builtin-list.c b/tools/perf/builtin-list.c
index f3750331e8f6..137d73edb541 100644
--- a/tools/perf/builtin-list.c
+++ b/tools/perf/builtin-list.c
@@ -17,6 +17,7 @@
 #include "util/metricgroup.h"
 #include "util/string2.h"
 #include "util/strlist.h"
+#include "util/strbuf.h"
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
 #include <linux/zalloc.h>
@@ -250,45 +251,56 @@ static void json_print_end(void *ps)
 	printf("%s]\n", print_state->need_sep ? "\n" : "");
 }
 
-static void fix_escape_printf(const char *fmt, ...)
+static void fix_escape_printf(struct strbuf *buf, const char *fmt, ...)
 {
 	va_list args;
-	char buf[2048];
-	size_t buf_pos = 0;
 
 	va_start(args, fmt);
+	strbuf_setlen(buf, 0);
 	for (size_t fmt_pos = 0; fmt_pos < strlen(fmt); fmt_pos++) {
 		switch (fmt[fmt_pos]) {
-		case '%': {
-			const char *s = va_arg(args, const char*);
-
+		case '%':
 			fmt_pos++;
-			assert(fmt[fmt_pos] == 's');
-			for (size_t s_pos = 0; s_pos < strlen(s); s_pos++) {
-				switch (s[s_pos]) {
-				case '\\':
-					__fallthrough;
-				case '\"':
-					buf[buf_pos++] = '\\';
-					assert(buf_pos < sizeof(buf));
-					__fallthrough;
-				default:
-					buf[buf_pos++] = s[s_pos];
-					assert(buf_pos < sizeof(buf));
-					break;
+			switch (fmt[fmt_pos]) {
+			case 's': {
+				const char *s = va_arg(args, const char*);
+
+				strbuf_addstr(buf, s);
+				break;
+			}
+			case 'S': {
+				const char *s = va_arg(args, const char*);
+
+				for (size_t s_pos = 0; s_pos < strlen(s); s_pos++) {
+					switch (s[s_pos]) {
+					case '\n':
+						strbuf_addstr(buf, "\\n");
+						break;
+					case '\\':
+						__fallthrough;
+					case '\"':
+						strbuf_addch(buf, '\\');
+						__fallthrough;
+					default:
+						strbuf_addch(buf, s[s_pos]);
+						break;
+					}
 				}
+				break;
+			}
+			default:
+				pr_err("Unexpected format character '%c'\n", fmt[fmt_pos]);
+				strbuf_addch(buf, '%');
+				strbuf_addch(buf, fmt[fmt_pos]);
 			}
 			break;
-		}
 		default:
-			buf[buf_pos++] = fmt[fmt_pos];
-			assert(buf_pos < sizeof(buf));
+			strbuf_addch(buf, fmt[fmt_pos]);
 			break;
 		}
 	}
 	va_end(args);
-	buf[buf_pos] = '\0';
-	fputs(buf, stdout);
+	fputs(buf->buf, stdout);
 }
 
 static void json_print_event(void *ps, const char *pmu_name, const char *topic,
@@ -301,62 +313,71 @@ static void json_print_event(void *ps, const char *pmu_name, const char *topic,
 {
 	struct json_print_state *print_state = ps;
 	bool need_sep = false;
+	struct strbuf buf;
 
+	strbuf_init(&buf, 0);
 	printf("%s{\n", print_state->need_sep ? ",\n" : "");
 	print_state->need_sep = true;
 	if (pmu_name) {
-		fix_escape_printf("\t\"Unit\": \"%s\"", pmu_name);
+		fix_escape_printf(&buf, "\t\"Unit\": \"%S\"", pmu_name);
 		need_sep = true;
 	}
 	if (topic) {
-		fix_escape_printf("%s\t\"Topic\": \"%s\"", need_sep ? ",\n" : "", topic);
+		fix_escape_printf(&buf, "%s\t\"Topic\": \"%S\"", need_sep ? ",\n" : "", topic);
 		need_sep = true;
 	}
 	if (event_name) {
-		fix_escape_printf("%s\t\"EventName\": \"%s\"", need_sep ? ",\n" : "", event_name);
+		fix_escape_printf(&buf, "%s\t\"EventName\": \"%S\"", need_sep ? ",\n" : "",
+				  event_name);
 		need_sep = true;
 	}
 	if (event_alias && strlen(event_alias)) {
-		fix_escape_printf("%s\t\"EventAlias\": \"%s\"", need_sep ? ",\n" : "", event_alias);
+		fix_escape_printf(&buf, "%s\t\"EventAlias\": \"%S\"", need_sep ? ",\n" : "",
+				  event_alias);
 		need_sep = true;
 	}
 	if (scale_unit && strlen(scale_unit)) {
-		fix_escape_printf("%s\t\"ScaleUnit\": \"%s\"", need_sep ? ",\n" : "",
+		fix_escape_printf(&buf, "%s\t\"ScaleUnit\": \"%S\"", need_sep ? ",\n" : "",
 				  scale_unit);
 		need_sep = true;
 	}
 	if (event_type_desc) {
-		fix_escape_printf("%s\t\"EventType\": \"%s\"", need_sep ? ",\n" : "",
+		fix_escape_printf(&buf, "%s\t\"EventType\": \"%S\"", need_sep ? ",\n" : "",
 				  event_type_desc);
 		need_sep = true;
 	}
 	if (deprecated) {
-		fix_escape_printf("%s\t\"Deprecated\": \"%s\"", need_sep ? ",\n" : "",
+		fix_escape_printf(&buf, "%s\t\"Deprecated\": \"%S\"", need_sep ? ",\n" : "",
 				  deprecated ? "1" : "0");
 		need_sep = true;
 	}
 	if (desc) {
-		fix_escape_printf("%s\t\"BriefDescription\": \"%s\"", need_sep ? ",\n" : "", desc);
+		fix_escape_printf(&buf, "%s\t\"BriefDescription\": \"%S\"", need_sep ? ",\n" : "",
+				  desc);
 		need_sep = true;
 	}
 	if (long_desc) {
-		fix_escape_printf("%s\t\"PublicDescription\": \"%s\"", need_sep ? ",\n" : "",
+		fix_escape_printf(&buf, "%s\t\"PublicDescription\": \"%S\"", need_sep ? ",\n" : "",
 				  long_desc);
 		need_sep = true;
 	}
 	if (encoding_desc) {
-		fix_escape_printf("%s\t\"Encoding\": \"%s\"", need_sep ? ",\n" : "", encoding_desc);
+		fix_escape_printf(&buf, "%s\t\"Encoding\": \"%S\"", need_sep ? ",\n" : "",
+				  encoding_desc);
 		need_sep = true;
 	}
 	if (metric_name) {
-		fix_escape_printf("%s\t\"MetricName\": \"%s\"", need_sep ? ",\n" : "", metric_name);
+		fix_escape_printf(&buf, "%s\t\"MetricName\": \"%S\"", need_sep ? ",\n" : "",
+				  metric_name);
 		need_sep = true;
 	}
 	if (metric_expr) {
-		fix_escape_printf("%s\t\"MetricExpr\": \"%s\"", need_sep ? ",\n" : "", metric_expr);
+		fix_escape_printf(&buf, "%s\t\"MetricExpr\": \"%S\"", need_sep ? ",\n" : "",
+				  metric_expr);
 		need_sep = true;
 	}
 	printf("%s}", need_sep ? "\n" : "");
+	strbuf_release(&buf);
 }
 
 static void json_print_metric(void *ps __maybe_unused, const char *group,
@@ -366,35 +387,39 @@ static void json_print_metric(void *ps __maybe_unused, const char *group,
 {
 	struct json_print_state *print_state = ps;
 	bool need_sep = false;
+	struct strbuf buf;
 
+	strbuf_init(&buf, 0);
 	printf("%s{\n", print_state->need_sep ? ",\n" : "");
 	print_state->need_sep = true;
 	if (group) {
-		fix_escape_printf("\t\"MetricGroup\": \"%s\"", group);
+		fix_escape_printf(&buf, "\t\"MetricGroup\": \"%S\"", group);
 		need_sep = true;
 	}
 	if (name) {
-		fix_escape_printf("%s\t\"MetricName\": \"%s\"", need_sep ? ",\n" : "", name);
+		fix_escape_printf(&buf, "%s\t\"MetricName\": \"%S\"", need_sep ? ",\n" : "", name);
 		need_sep = true;
 	}
 	if (expr) {
-		fix_escape_printf("%s\t\"MetricExpr\": \"%s\"", need_sep ? ",\n" : "", expr);
+		fix_escape_printf(&buf, "%s\t\"MetricExpr\": \"%S\"", need_sep ? ",\n" : "", expr);
 		need_sep = true;
 	}
 	if (unit) {
-		fix_escape_printf("%s\t\"ScaleUnit\": \"%s\"", need_sep ? ",\n" : "", unit);
+		fix_escape_printf(&buf, "%s\t\"ScaleUnit\": \"%S\"", need_sep ? ",\n" : "", unit);
 		need_sep = true;
 	}
 	if (desc) {
-		fix_escape_printf("%s\t\"BriefDescription\": \"%s\"", need_sep ? ",\n" : "", desc);
+		fix_escape_printf(&buf, "%s\t\"BriefDescription\": \"%S\"", need_sep ? ",\n" : "",
+				  desc);
 		need_sep = true;
 	}
 	if (long_desc) {
-		fix_escape_printf("%s\t\"PublicDescription\": \"%s\"", need_sep ? ",\n" : "",
+		fix_escape_printf(&buf, "%s\t\"PublicDescription\": \"%S\"", need_sep ? ",\n" : "",
 				  long_desc);
 		need_sep = true;
 	}
 	printf("%s}", need_sep ? "\n" : "");
+	strbuf_release(&buf);
 }
 
 int cmd_list(int argc, const char **argv)
-- 
2.38.1.584.g0f3c55d4c2-goog


  parent reply	other threads:[~2022-11-18  2:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-18  2:46 [PATCH v2 0/3] perf list libpfm fixes Ian Rogers
2022-11-18  2:46 ` [PATCH v2 1/3] perf list: Support newlines in wordwrap Ian Rogers
2022-11-18  2:46 ` Ian Rogers [this message]
2022-11-18  2:46 ` [PATCH v2 3/3] perf list: List callback support for libpfm Ian Rogers
2022-11-24 13:06 ` [PATCH v2 0/3] perf list libpfm fixes Arnaldo Carvalho de Melo

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