CharReader: Add ErrorInfo and parse() overload

Author: KyleFromKitware

Diff for: include/json/reader.h

@@ -244,6 +244,13 @@ class JSONCPP_DEPRECATED(
  */
 class JSON_API CharReader {
 public:
+  class JSON_API ErrorInfo {
+  public:
+    ptrdiff_t offset_start;
+    ptrdiff_t offset_limit;
+    String message;
+  };
+
   virtual ~CharReader() = default;
   /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
    * document. The document must be a UTF-8 encoded string containing the
@@ -264,6 +271,24 @@ class JSON_API CharReader {
   virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
                      String* errs) = 0;
 
+  /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
+   * document. The document must be a UTF-8 encoded string containing the
+   * document to read.
+   *
+   * \param      beginDoc Pointer on the beginning of the UTF-8 encoded string
+   *                      of the document to read.
+   * \param      endDoc   Pointer on the end of the UTF-8 encoded string of the
+   *                      document to read. Must be >= beginDoc.
+   * \param[out] root     Contains the root value of the document if it was
+   *                      successfully parsed.
+   * \param[out] errs     Structured error messages a list of items that list
+   *                      errors in the parsed document.
+   * \return \c true if the document was successfully parsed, \c false if an
+   * error occurred.
+   */
+  virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
+                     std::vector<ErrorInfo>& errs) = 0;
+
   class JSON_API Factory {
   public:
     virtual ~Factory() = default;

Diff for: src/lib_json/json_reader.cpp

@@ -884,17 +884,12 @@ class OurReader {
 public:
   using Char = char;
   using Location = const Char*;
-  struct StructuredError {
-    ptrdiff_t offset_start;
-    ptrdiff_t offset_limit;
-    String message;
-  };
 
   explicit OurReader(OurFeatures const& features);
   bool parse(const char* beginDoc, const char* endDoc, Value& root,
              bool collectComments = true);
   String getFormattedErrorMessages() const;
-  std::vector<StructuredError> getStructuredErrors() const;
+  std::vector<CharReader::ErrorInfo> getErrorInfo() const;
 
 private:
   OurReader(OurReader const&);      // no impl
@@ -1849,14 +1844,14 @@ String OurReader::getFormattedErrorMessages() const {
   return formattedMessage;
 }
 
-std::vector<OurReader::StructuredError> OurReader::getStructuredErrors() const {
-  std::vector<OurReader::StructuredError> allErrors;
+std::vector<CharReader::ErrorInfo> OurReader::getErrorInfo() const {
+  std::vector<CharReader::ErrorInfo> allErrors;
   for (const auto& error : errors_) {
-    OurReader::StructuredError structured;
-    structured.offset_start = error.token_.start_ - begin_;
-    structured.offset_limit = error.token_.end_ - begin_;
-    structured.message = error.message_;
-    allErrors.push_back(structured);
+    CharReader::ErrorInfo errorInfo;
+    errorInfo.offset_start = error.token_.start_ - begin_;
+    errorInfo.offset_limit = error.token_.end_ - begin_;
+    errorInfo.message = error.message_;
+    allErrors.push_back(errorInfo);
   }
   return allErrors;
 }
@@ -1876,6 +1871,13 @@ class OurCharReader : public CharReader {
     }
     return ok;
   }
+
+  bool parse(char const* beginDoc, char const* endDoc, Value* root,
+             std::vector<ErrorInfo>& errs) override {
+    bool ok = reader_.parse(beginDoc, endDoc, *root, collectComments_);
+    errs = reader_.getErrorInfo();
+    return ok;
+  }
 };
 
 CharReaderBuilder::CharReaderBuilder() { setDefaults(&settings_); }

Diff for: src/test_lib_json/main.cpp

@@ -3903,6 +3903,32 @@ JSONTEST_FIXTURE_LOCAL(FuzzTest, fuzzDoesntCrash) {
                              example.size()));
 }
 
+struct ParseWithErrorInfoTest : JsonTest::TestCase {};
+
+JSONTEST_FIXTURE_LOCAL(ParseWithErrorInfoTest, success) {
+  Json::CharReaderBuilder b;
+  CharReaderPtr reader(b.newCharReader());
+  char const doc[] = "{}";
+  Json::Value root;
+  std::vector<Json::CharReader::ErrorInfo> errs;
+  JSONTEST_ASSERT(reader->parse(doc, doc + std::strlen(doc), &root, errs));
+  JSONTEST_ASSERT_EQUAL(0, errs.size());
+}
+
+JSONTEST_FIXTURE_LOCAL(ParseWithErrorInfoTest, singleError) {
+  Json::CharReaderBuilder b;
+  CharReaderPtr reader(b.newCharReader());
+  char const doc[] = R"({ 1: 2 })";
+  Json::Value root;
+  std::vector<Json::CharReader::ErrorInfo> errs;
+  JSONTEST_ASSERT(!reader->parse(doc, doc + std::strlen(doc), &root, errs));
+  JSONTEST_ASSERT_EQUAL(1, errs.size());
+  JSONTEST_ASSERT_EQUAL(std::string("Missing '}' or object member name"),
+                        errs[0].message);
+  JSONTEST_ASSERT_EQUAL(2, errs[0].offset_start);
+  JSONTEST_ASSERT_EQUAL(3, errs[0].offset_limit);
+}
+
 int main(int argc, const char* argv[]) {
   JsonTest::Runner runner;