Fix dbConstLink to handle a long-string array properly

Added a new parser dbLSConvertJSON for long-string arrays.
New test checks that only the first string element is used.

src/ioc/db/dbConstLink.c

@@ -73,26 +73,11 @@ static long dbConstLoadLS(struct link *plink, char *pbuffer, epicsUInt32 size,
     epicsUInt32 *plen)
 {
     const char *pstr = plink->value.constantStr;
-    size_t len;
 
     if (!pstr)
         return S_db_badField;
-    if (!size)
-        return 0;
-    len = strlen(pstr);
 
-    /* FIXME This handles the common case, but not the general one... */
-    if (pstr[0] == '[' && pstr[1] == '"' &&
-        pstr[len-2] == '"' && pstr[len-1] == ']') {
-        pstr += 2;
-        len -= 4;
-    }
-    if (len+1 > size) len = size-1;
-
-    memcpy(pbuffer, pstr, len);
-    pbuffer[len] = 0;
-    *plen = len+1;
-    return 0;
+    return dbLSConvertJSON(pstr, pbuffer, size, plen);
 }
 
 static long dbConstLoadArray(struct link *plink, short dbrType, void *pbuffer,

src/ioc/db/dbConvertJSON.c

@@ -17,6 +17,7 @@
 #define epicsExportSharedSymbols
 #include "dbAccessDefs.h"
 #include "dbConvertFast.h"
+#include "dbConvertJSON.h"
 
 typedef long (*FASTCONVERT)();
 
@@ -49,6 +50,10 @@ static int dbcj_integer(void *ctx, long num) {
     return 1;
 }
 
+static int dblsj_integer(void *ctx, long num) {
+    return 0;    /* Illegal */
+}
+
 static int dbcj_double(void *ctx, double num) {
     parseContext *parser = (parseContext *) ctx;
     FASTCONVERT conv = dbFastPutConvertRoutine[DBF_DOUBLE][parser->dbrType];
@@ -61,6 +66,10 @@ static int dbcj_double(void *ctx, double num) {
     return 1;
 }
 
+static int dblsj_double(void *ctx, double num) {
+    return 0;    /* Illegal */
+}
+
 static int dbcj_string(void *ctx, const unsigned char *val, unsigned int len) {
     parseContext *parser = (parseContext *) ctx;
     char *pdest = parser->pdest;
@@ -69,7 +78,7 @@ static int dbcj_string(void *ctx, const unsigned char *val, unsigned int len) {
      * metadata about the field than we have available at the moment.
      */
     if (parser->dbrType != DBF_STRING) {
-        errlogPrintf("dbPutConvertJSON: String provided, numeric value(s) expected\n");
+        errlogPrintf("dbConvertJSON: String provided, numeric value(s) expected\n");
         return 0; /* Illegal */
     }
 
@@ -84,8 +93,28 @@ static int dbcj_string(void *ctx, const unsigned char *val, unsigned int len) {
     return 1;
 }
 
+static int dblsj_string(void *ctx, const unsigned char *val, unsigned int len) {
+    parseContext *parser = (parseContext *) ctx;
+    char *pdest = parser->pdest;
+
+    if (parser->dbrType != DBF_STRING) {
+        errlogPrintf("dbConvertJSON: dblsj_string dbrType error\n");
+        return 0; /* Illegal */
+    }
+
+    if (parser->elems > 0) {
+        if (len > parser->dbrSize - 1)
+            len = parser->dbrSize - 1;
+        strncpy(pdest, (const char *) val, len);
+        pdest[len] = 0;
+        parser->pdest = pdest + len;
+        parser->elems = 0;
+    }
+    return 1;
+}
+
 static int dbcj_start_map(void *ctx) {
-    errlogPrintf("dbPutConvertJSON: Map type not supported\n");
+    errlogPrintf("dbConvertJSON: Map type not supported\n");
     return 0;    /* Illegal */
 }
 
@@ -101,7 +130,7 @@ static int dbcj_start_array(void *ctx) {
     parseContext *parser = (parseContext *) ctx;
 
     if (++parser->depth > 1) 
-        errlogPrintf("dbPutConvertJSON: Embedded arrays not supported\n");
+        errlogPrintf("dbConvertJSON: Embedded arrays not supported\n");
 
     return (parser->depth == 1);
 }
@@ -157,7 +186,7 @@ long dbPutConvertJSON(const char *json, short dbrType,
     case yajl_status_error: {
         unsigned char *err = yajl_get_error(yh, 1,
             (const unsigned char *) json, (unsigned int) jlen);
-        fprintf(stderr, "dbPutConvertJSON: %s\n", err);
+        fprintf(stderr, "dbConvertJSON: %s\n", err);
         yajl_free_error(yh, err);
         }
         /* fall through */
@@ -170,3 +199,59 @@ long dbPutConvertJSON(const char *json, short dbrType,
 }
 
 
+static yajl_callbacks dblsj_callbacks = {
+    dbcj_null, dbcj_boolean, dblsj_integer, dblsj_double, NULL, dblsj_string,
+    dbcj_start_map, dbcj_map_key, dbcj_end_map,
+    dbcj_start_array, dbcj_end_array
+};
+
+long dbLSConvertJSON(const char *json, char *pdest, epicsUInt32 size,
+    epicsUInt32 *plen)
+{
+    parseContext context, *parser = &context;
+    yajl_alloc_funcs dbcj_alloc;
+    yajl_handle yh;
+    yajl_status ys;
+    size_t jlen = strlen(json);
+    long status;
+
+    if (!size) {
+        *plen = 0;
+        return 0;
+    }
+
+    parser->depth = 0;
+    parser->dbrType = DBF_STRING;
+    parser->dbrSize = size;
+    parser->pdest = pdest;
+    parser->elems = 1;
+
+    yajl_set_default_alloc_funcs(&dbcj_alloc);
+    yh = yajl_alloc(&dblsj_callbacks, &dbcj_config, &dbcj_alloc, parser);
+    if (!yh)
+        return S_db_noMemory;
+
+    ys = yajl_parse(yh, (const unsigned char *) json, (unsigned int) jlen);
+    if (ys == yajl_status_insufficient_data)
+        ys = yajl_parse_complete(yh);
+
+    switch (ys) {
+    case yajl_status_ok:
+        *plen = (char *) parser->pdest - pdest + 1;
+        status = 0;
+        break;
+
+    case yajl_status_error: {
+        unsigned char *err = yajl_get_error(yh, 1,
+            (const unsigned char *) json, (unsigned int) jlen);
+        fprintf(stderr, "dbLoadLS_JSON: %s\n", err);
+        yajl_free_error(yh, err);
+        }
+        /* fall through */
+    default:
+        status = S_db_badField;
+    }
+
+    yajl_free(yh);
+    return status;
+}

src/ioc/db/dbConvertJSON.h

@@ -18,7 +18,8 @@ extern "C" {
 /* This name should probably be changed to inclue "array" */
 epicsShareFunc long dbPutConvertJSON(const char *json, short dbrType,
     void *pdest, long *psize);
-
+epicsShareFunc long dbLSConvertJSON(const char *json, char *pdest,
+    epicsUInt32 size, epicsUInt32 *plen);
 #ifdef __cplusplus
 }
 #endif

src/std/rec/test/linkInitTest.c

@@ -53,6 +53,8 @@ static void testLongStringInit()
         testdbGetFieldEqual("longstr3.VAL", DBR_STRING, "!--------------------------------------");
     }
 
+    testdbGetFieldEqual("longstr4.VAL", DBR_STRING, "One");
+
     testIocShutdownOk();
 
     testdbCleanup();
@@ -149,7 +151,7 @@ static void testPrintfInit()
 
 MAIN(linkInitTest)
 {
-    testPlan(30);
+    testPlan(31);
     testLongStringInit();
     testCalcInit();
     testPrintfInit();

src/std/rec/test/linkInitTest.db

@@ -1,4 +1,3 @@
-
 record(lsi, "longstr1") {
   field(SIZV, "100")
   field(INP, ["!----------------------------------------------!"])
@@ -14,6 +13,10 @@ record(lsi, "longstr3") {
   field(INP, {const: "!----------------------------------------------!"})
 }
 
+record(stringin, "longstr4") {
+  field(INP, ["One","Two","Three","Four"])
+}
+
 record(ai, "emptylink" ) {
   field(INP, {calc: {expr:"0"}})
 }