tp: fix parsing of unknown values in top level of JSON trace
Skip any values we don't know with a single skip function - this
unifies our handling of any keys regardless of type.
Change-Id: I52555d71acff9fece117482f02af6260364c6229
Bug: https://github.com/google/perfetto/issues/365
diff --git a/src/trace_processor/importers/json/json_trace_tokenizer.cc b/src/trace_processor/importers/json/json_trace_tokenizer.cc
index d57ad8b..b8c486f 100644
--- a/src/trace_processor/importers/json/json_trace_tokenizer.cc
+++ b/src/trace_processor/importers/json/json_trace_tokenizer.cc
@@ -110,6 +110,67 @@
return ReadStringRes::kNeedsMoreData;
}
+enum class SkipValueRes {
+ kEndOfValue,
+ kNeedsMoreData,
+ kFatalError,
+};
+SkipValueRes SkipOneJsonValue(const char* start,
+ const char* end,
+ const char** next) {
+ uint32_t brace_count = 0;
+ uint32_t bracket_count = 0;
+ for (const char* s = start; s < end; s++) {
+ if (*s == '"') {
+ // Because strings can contain {}[] characters, handle them separately
+ // before anything else.
+ std::string ignored;
+ const char* str_next = nullptr;
+ switch (ReadOneJsonString(s, end, &ignored, &str_next)) {
+ case ReadStringRes::kFatalError:
+ return SkipValueRes::kFatalError;
+ case ReadStringRes::kNeedsMoreData:
+ return SkipValueRes::kNeedsMoreData;
+ case ReadStringRes::kEndOfString:
+ // -1 as the loop body will +1 getting to the correct place.
+ s = str_next - 1;
+ break;
+ }
+ continue;
+ }
+ if (brace_count == 0 && bracket_count == 0 && (*s == ',' || *s == '}')) {
+ // If we're at the outermost level and we see a comma or a closing brace,
+ // we've hit the end of the value.
+ // +1 so we skip the closing comma/brace itself.
+ *next = s + 1;
+ return SkipValueRes::kEndOfValue;
+ }
+ if (*s == '[') {
+ ++bracket_count;
+ continue;
+ }
+ if (*s == ']') {
+ if (bracket_count == 0) {
+ return SkipValueRes::kFatalError;
+ }
+ --bracket_count;
+ continue;
+ }
+ if (*s == '{') {
+ ++brace_count;
+ continue;
+ }
+ if (*s == '}') {
+ if (brace_count == 0) {
+ return SkipValueRes::kFatalError;
+ }
+ --brace_count;
+ continue;
+ }
+ }
+ return SkipValueRes::kNeedsMoreData;
+}
+
} // namespace
ReadDictRes ReadOneJsonDict(const char* start,
@@ -278,8 +339,11 @@
if (res == ReadKeyRes::kEndOfDictionary)
break;
- if (res == ReadKeyRes::kFatalError)
- return util::ErrStatus("Failure parsing JSON: encountered fatal error");
+ if (res == ReadKeyRes::kFatalError) {
+ return util::ErrStatus(
+ "Failure parsing JSON: encountered fatal error while parsing key for "
+ "value");
+ }
if (res == ReadKeyRes::kNeedsMoreData) {
return util::ErrStatus("Failure parsing JSON: partial JSON dictionary");
@@ -432,8 +496,10 @@
std::string key;
ReadKeyRes res = ReadOneJsonKey(start, end, &key, &next);
- if (res == ReadKeyRes::kFatalError)
- return util::ErrStatus("Failure parsing JSON: encountered fatal error");
+ if (res == ReadKeyRes::kFatalError) {
+ return util::ErrStatus(
+ "Failure parsing JSON: encountered fatal error while parsing key");
+ }
if (res == ReadKeyRes::kEndOfDictionary ||
res == ReadKeyRes::kNeedsMoreData) {
@@ -477,40 +543,16 @@
return ParseInternal(next, end, out);
}
- // If we don't recognize the key, check if it could be a string or dict.
- // If either of them, parse it and throw it away to move onto the next
- // key.
- if (*next == '"') {
- std::string ignored;
- ReadStringRes value_res = ReadOneJsonString(next, end, &ignored, &next);
- if (value_res == ReadStringRes::kFatalError) {
+ // If we don't know the key for this JSON value just skip it.
+ switch (SkipOneJsonValue(next, end, &next)) {
+ case SkipValueRes::kFatalError:
return base::ErrStatus(
- "Failure parsing JSON: unable to read string for key %s",
+ "Failure parsing JSON: error while parsing value for key %s",
key.c_str());
- }
- if (value_res == ReadStringRes::kNeedsMoreData) {
- break;
- }
- return ParseInternal(next, end, out);
+ case SkipValueRes::kNeedsMoreData:
+ case SkipValueRes::kEndOfValue:
+ return ParseInternal(next, end, out);
}
- if (*next == '{') {
- base::StringView ignored;
- ReadDictRes value_res = ReadOneJsonDict(next, end, &ignored, &next);
- if (value_res == ReadDictRes::kEndOfTrace ||
- value_res == ReadDictRes::kEndOfArray) {
- return util::ErrStatus(
- "Failure parsing JSON: unable to read dict for key %s",
- key.c_str());
- }
- if (value_res == ReadDictRes::kNeedsMoreData) {
- break;
- }
- return ParseInternal(next, end, out);
- }
-
- // Otherwise, just jump to the end of the trace.
- // TODO(lalitm): do something better here.
- position_ = TracePosition::kEof;
break;
}
case TracePosition::kInsideSystemTraceEventsString: {
@@ -522,9 +564,11 @@
while (next < end) {
std::string raw_line;
auto res = ReadOneSystemTraceLine(next, end, &raw_line, &next);
- if (res == ReadSystemLineRes::kFatalError)
+ if (res == ReadSystemLineRes::kFatalError) {
return util::ErrStatus(
- "Failure parsing JSON: encountered fatal error");
+ "Failure parsing JSON: encountered fatal error while parsing "
+ "event inside trace event string");
+ }
if (res == ReadSystemLineRes::kNeedsMoreData)
break;
