webmap-import: Improve OGRFieldDefn::[GS]et*() capability detection.

The PostgreSQL driver doesn't support AlternativeName, for instance.

1 files changed, 48 insertions, 30 deletions

diff --git a/webmap-import b/webmap-import
index 8512e6d..c1d07a3 100755
--- a/webmap-import
+++ b/webmap-import
@@ -330,19 +330,44 @@ def formatTZFlag(tzFlag):
     tzSign = '+' if tzFlag > 100 else '-'
     return f'{tzSign}{tzHour:02}{tzMinute:02}'
 
+def setFieldIf(cond, attrName, val, data, fldName, drvName, log=logging.warning):
+    if cond:
+        data[attrName] = val
+    else:
+        if isinstance(val, str):
+            val2 = '"' + val + '"'
+        else:
+            val2 = str(val)
+        log('Ignoring %s=%s on field "%s" (not supported by %s driver)',
+            attrName, val2, fldName, drvName)
+
 # Validate layer creation options and schema.  The schema is modified in
 # place with the parsed result.
 # (We need the driver of the output dataset to determine capability on
 # constraints.)
 def validateSchema(layers, drvo=None, lco_defaults=None):
-    # cache driver capabilities
-    drvoSupportsDefaultFields = getMetadataItem(drvo, GDAL_DCAP_DEFAULT_FIELDS)
-    drvoSupportsNotNULLFields = getMetadataItem(drvo, GDAL_DCAP_NOTNULL_FIELDS)
-    drvoSupportsUniqueFields  = getMetadataItem(drvo, GDAL_DCAP_UNIQUE_FIELDS)
-
     # Cf. https://github.com/OSGeo/gdal/blob/master/NEWS.md
-    hasCommentSupport = common.gdal_version_min(maj=3, min=7) # GetComment()/SetComment() added in 3.7.0
-    hasTZFlagSupport  = common.gdal_version_min(maj=3, min=8) # GetTZFlag()/SetTZFlag() and OGR_TZFLAG_* constants added in 3.8.0
+    if common.gdal_version_min(maj=3, min=7):
+        # list of capability flags supported by the CreateField() API
+        drvoFieldDefnFlags = drvo.GetMetadataItem(gdalconst.DMD_CREATION_FIELD_DEFN_FLAGS)
+        drvoFieldDefnFlags = drvoFieldDefnFlags.split(' ') if drvoFieldDefnFlags is not None else []
+        drvoSupportsFieldComment = 'Comment' in drvoFieldDefnFlags
+        # GetTZFlag()/SetTZFlag() and OGR_TZFLAG_* constants added in 3.8.0
+        hasTZFlagSupport = common.gdal_version_min(maj=3, min=8)
+    else:
+        # list of flags supported by the OGRLayer::AlterFieldDefn() API
+        drvoFieldDefnFlags = drvo.GetMetadataItem(gdalconst.DMD_ALTER_FIELD_DEFN_FLAGS)
+        drvoFieldDefnFlags = drvoFieldDefnFlags.split(' ') if drvoFieldDefnFlags is not None else []
+        # GetComment()/SetComment() added in 3.7.0
+        drvoSupportsFieldComment = False
+        hasTZFlagSupport = False
+
+    # cache driver capabilities
+    drvoSupportsFieldWidthPrecision = 'WidthPrecision' in drvoFieldDefnFlags
+    drvoSupportsFieldNullable = 'Nullable' in drvoFieldDefnFlags and getMetadataItem(drvo, GDAL_DCAP_NOTNULL_FIELDS)
+    drvoSupportsFieldUnique   = 'Unique'   in drvoFieldDefnFlags and getMetadataItem(drvo, GDAL_DCAP_UNIQUE_FIELDS)
+    drvoSupportsFieldDefault  = 'Default'  in drvoFieldDefnFlags and getMetadataItem(drvo, GDAL_DCAP_DEFAULT_FIELDS)
+    drvoSupportsFieldAlternativeName = 'AlternativeName' in drvoFieldDefnFlags
 
     for layername, layerdef in layers.items():
         create = layerdef.get('create', None)
@@ -383,13 +408,13 @@ def validateSchema(layers, drvo=None, lco_defaults=None):
                     if k2 == 'name':
                         pass
                     elif k2 == 'alternativename' or k2 == 'alias':
-                        fld_def2['AlternativeName'] = v
+                        setFieldIf(drvoSupportsFieldAlternativeName,
+                            'AlternativeName', v, fld_def2, fld_name, drvo.ShortName,
+                            log=logging.debug)
                     elif k2 == 'comment':
-                        if hasCommentSupport:
-                            fld_def2['Comment'] = v
-                        else:
-                            logging.debug('Ignoring Comment="%s" on field "%s" (OGR v%s is too old)',
-                                v, fld_name, gdal.__version__)
+                        setFieldIf(drvoSupportsFieldComment,
+                            'Comment', v, fld_def2, fld_name, drvo.ShortName,
+                            log=logging.debug)
 
                     elif k2 == 'type':
                         fld_def2['Type'] = parseFieldType(v)
@@ -402,29 +427,22 @@ def validateSchema(layers, drvo=None, lco_defaults=None):
                             logging.debug('Ignoring TZ="%s" on field "%s" (OGR v%s is too old)',
                                 v, fld_name, gdal.__version__)
                     elif k2 == 'width' and v is not None and isinstance(v, int):
-                        fld_def2['Width'] = v
+                        setFieldIf(drvoSupportsFieldWidthPrecision,
+                            'Width', v, fld_def2, fld_name, drvo.ShortName)
                     elif k2 == 'precision' and v is not None and isinstance(v, int):
-                        fld_def2['Precision'] = v
+                        setFieldIf(drvoSupportsFieldWidthPrecision,
+                            'Precision', v, fld_def2, fld_name, drvo.ShortName)
 
                     # constraints
                     elif k2 == 'default':
-                        if drvoSupportsDefaultFields:
-                            fld_def2['Default'] = v
-                        else:
-                            logging.warning('%s driver lacks GDAL_DCAP_DEFAULT_FIELDS support',
-                                drvo.ShortName)
+                        setFieldIf(drvoSupportsFieldDefault,
+                            'Default', v, fld_def2, fld_name, drvo.ShortName)
                     elif k2 == 'nullable' and v is not None and isinstance(v, bool):
-                        if drvoSupportsNotNULLFields:
-                            fld_def2['Nullable'] = v
-                        else:
-                            logging.warning('%s driver lacks GDAL_DCAP_NOTNULL_FIELDS support',
-                                drvo.ShortName)
+                        setFieldIf(drvoSupportsFieldNullable,
+                            'Nullable', v, fld_def2, fld_name, drvo.ShortName)
                     elif k2 == 'unique' and v is not None and isinstance(v, bool):
-                        if drvoSupportsUniqueFields:
-                            fld_def2['Unique'] = v
-                        else:
-                            logging.warning('%s driver lacks GDAL_DCAP_UNIQUE_FIELDS support',
-                                drvo.ShortName)
+                        setFieldIf(drvoSupportsFieldUnique,
+                            'Unique', v, fld_def2, fld_name, drvo.ShortName)
                     else:
                         raise Exception(f'Field "{fld_name}" has unknown key "{k}"')