"blob" fields: Added separate CONVMODE_BLOB_AUTO conversion mode for fields that should be rendered as B64 only in case they are really non-printable or non-ASCIIbmc19661

This is an addition to 8d5cce896d ("blob" fields: avoid binary encoding if possible) to avoid change of behaviour for CONVMODE_BLOB_B64.

2 files changed, 23 insertions, 10 deletions

diff --git a/src/sysync/mimedirprofile.cpp b/src/sysync/mimedirprofile.cpp
index 1499876..c8fe995 100644
--- a/src/sysync/mimedirprofile.cpp
+++ b/src/sysync/mimedirprofile.cpp
@@ -175,6 +175,8 @@ bool TMIMEProfileConfig::getConvMode(cAppCharP aText, sInt16 &aConvMode)
       aConvMode = CONVMODE_MULTIMIX;
     else if (strucmp(aText,"blob_b64",n)==0)
       aConvMode = CONVMODE_BLOB_B64;
+    else if (strucmp(aText,"blob_auto",n)==0)
+      aConvMode = CONVMODE_BLOB_AUTO;
     else if (strucmp(aText,"mailto",n)==0)
       aConvMode = CONVMODE_MAILTO;
     else if (strucmp(aText,"valuetype",n)==0)
@@ -2260,7 +2262,8 @@ sInt16 TMimeDirProfileHandler::generateValue(
           maxSiz = 0; // no size restriction
         bool noTruncate=aItem.getTargetItemType()->getFieldOptions(fid)->notruncate;
         // check for BLOB values
-        if ((aConvDefP->convmode & CONVMODE_MASK)==CONVMODE_BLOB_B64) {
+        sInt16 convmode = aConvDefP->convmode & CONVMODE_MASK;
+        if (convmode==CONVMODE_BLOB_B64 || convmode==CONVMODE_BLOB_AUTO) {
           // no value lists, escaping, enums. Simply set value and encoding
           TItemField *fldP = aItem.getArrayField(fid,aRepOffset,true); // existing array elements only
           if (!fldP) return GENVALUE_EXHAUSTED; // no leaf field - must be exhausted array (fldP==NULL is not possible here for non-arrays)
@@ -2275,16 +2278,22 @@ sInt16 TMimeDirProfileHandler::generateValue(
           }
           // append to existing string
           fldP->appendToString(outval,maxSiz);
-          // force B64 encoding if non-printable or non-ASCII characters
-          // are in the value
-          size_t len = outval.size();
-          for (size_t i = 0; i < len; i++) {
-            char c = outval[i];
-            if (!isascii(c) || !isprint(c)) {
-              aEncoding=enc_base64;
-              break;
+          if (convmode==CONVMODE_BLOB_AUTO) {
+            // auto mode: use  B64 encoding only if non-printable or
+            // non-ASCII characters are in the value
+            size_t len = outval.size();
+            for (size_t i = 0; i < len; i++) {
+              char c = outval[i];
+              if (!isascii(c) || !isprint(c)) {
+                aEncoding=enc_base64;
+                break;
+              }
             }
           }
+          else {
+            // blob mode: always use B64
+            aEncoding=enc_base64;
+          }
           // only ASCII in value: either because it contains only
           // those to start with or because they will be encoded
           aNonASCII=false;
@@ -3658,7 +3667,10 @@ bool TMimeDirProfileHandler::parseValue(
     // find out if value exists (available in source and target)
     if (isFieldAvailable(aItem,fid)) {
       // parse only if field available in both source and target
-      if ((aConvDefP->convmode & CONVMODE_MASK)==CONVMODE_BLOB_B64) {
+      if (
+        (aConvDefP->convmode & CONVMODE_MASK)==CONVMODE_BLOB_B64 ||
+        (aConvDefP->convmode & CONVMODE_MASK)==CONVMODE_BLOB_AUTO
+      ) {
         // move 1:1 into field
         // - get pointer to leaf field
         TItemField *fldP = aItem.getArrayField(fid,aRepOffset);
diff --git a/src/sysync/mimedirprofile.h b/src/sysync/mimedirprofile.h
index 4db8bdf..ed67fbf 100755
--- a/src/sysync/mimedirprofile.h
+++ b/src/sysync/mimedirprofile.h
@@ -49,6 +49,7 @@ namespace sysync {
 #define CONVMODE_VALUETYPE 14 // automatic VALUE parameter e.g. for timestamp fields that contain a date-only value (VALUE=DATE) or duration (VALUE=DURATION)
 #define CONVMODE_MULTIMIX 15 // special mode for mapping enums to bits (like CONVMODE_BITMAP), but mixed from multiple fields and with option to store as-is (special enum "value" syntax needed)
 #define CONVMODE_FULLVALUETYPE 16 // explicit VALUE parameter, does not assume a default
+#define CONVMODE_BLOB_AUTO 17 // like CONVMODE_BLOB_B64, but if data consists of printable ASCII-chars only, no B64 encoding is used
 
 // derived type modes start here
 #define CONVMODE_MIME_DERIVATES 20