json print/parse from/to PVStructure

src/json/parsehelper.cpp

@@ -0,0 +1,104 @@
+/*
+ * Copyright information and license terms for this software can be
+ * found in the file LICENSE that is included with the distribution
+ */
+
+#include <stdexcept>
+#include <sstream>
+
+#include <pv/pvdVersion.h>
+
+#if EPICS_VERSION_INT>=VERSION_INT(3,15,0,1)
+
+#define epicsExportSharedSymbols
+#include "pv/json.h"
+
+namespace {
+
+void check_trailing(const std::string& line, bool commentok)
+{
+    size_t idx = line.find_first_not_of(" \t\n\r");
+    if(idx==line.npos) return;
+    // TODO: detect the end of potentially multi-line comments...
+    // for now trailing comments not allowed
+    throw std::runtime_error("Trailing junk");
+}
+
+} // namespace
+
+namespace epics{namespace pvData{
+
+bool yajl_parse_helper(std::istream& src,
+                       yajl_handle handle,
+                       const yajl_parser_config& config)
+{
+    unsigned linenum=0;
+    bool done = false;
+
+    std::string line;
+    while(std::getline(src, line)) {
+        linenum++;
+
+        if(done) {
+            check_trailing(line, config.allowComments);
+            continue;
+        }
+
+        yajl_status sts = yajl_parse(handle, (const unsigned char*)line.c_str(), line.size());
+
+        switch(sts) {
+        case yajl_status_ok: {
+            size_t consumed = yajl_get_bytes_consumed(handle);
+            if(consumed<line.size()) {
+                check_trailing(line.substr(consumed), config.allowComments);
+            }
+            done = true;
+            break;
+        }
+        case yajl_status_client_canceled:
+            return false;
+        case yajl_status_insufficient_data:
+            // continue with next line
+            break;
+        case yajl_status_error:
+        {
+            std::ostringstream msg;
+            unsigned char *raw = yajl_get_error(handle, 1, (const unsigned char*)line.c_str(), line.size());
+            if(!raw) {
+                msg<<"Unknown error on line "<<linenum;
+            } else {
+                try {
+                    msg<<"Error on line "<<linenum<<" : "<<(const char*)raw;
+                }catch(...){
+                    yajl_free_error(handle, raw);
+                    throw;
+                }
+                yajl_free_error(handle, raw);
+            }
+            throw std::runtime_error(msg.str());
+        }
+        }
+    }
+
+    if(!src.eof() || src.bad()) {
+        std::ostringstream msg;
+        msg<<"I/O error after line "<<linenum;
+        throw std::runtime_error(msg.str());
+
+    } else if(!done) switch(yajl_parse_complete(handle)) {
+    case yajl_status_ok:
+        break;
+    case yajl_status_client_canceled:
+        return false;
+    case yajl_status_insufficient_data:
+        throw std::runtime_error("unexpected end of input");
+    case yajl_status_error:
+        throw std::runtime_error("Error while completing parsing");
+    }
+
+    return true;
+}
+
+}} // namespace epics::pvData
+
+#endif // EPICS_VERSION_INT