Garmin: Improve field cast safety

2026-07-31 07:44:24 +02:00 · 2026-01-13 22:08:54 +00:00
parent 8dad0e1da6
commit 0bdb76c6d4
3 changed files with 66 additions and 19 deletions
@@ -2,6 +2,7 @@ package nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit;

 import androidx.annotation.NonNull;

+import java.lang.reflect.Array;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -18,8 +19,11 @@ import nodomain.freeyourgadget.gadgetbridge.util.GBToStringBuilder;
 import static nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.baseTypes.BaseType.STRING;

 import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;

 public class RecordData {
+    private static final Logger LOG = LoggerFactory.getLogger(RecordData.class);

    private final RecordDefinition recordDefinition;
    private final RecordHeader recordHeader;
@@ -143,6 +147,59 @@ public class RecordData {
        return null;
    }

+    public <T> T getFieldByNumber(int number, final Class<T> clazz) {
+        return safeCast(getFieldByNumber(number), clazz);
+    }
+
+    public <T> T[] getArrayFieldByNumber(int number, final Class<T> clazz) {
+        final Object object = getFieldByNumber(number);
+        if (object == null)
+            return null;
+        if (!object.getClass().isArray()) {
+            final T casted = safeCast(object, clazz);
+            if (casted != null) {
+                @SuppressWarnings("unchecked")
+                final T[] ret = (T[]) Array.newInstance(clazz, 1);
+                ret[0] = casted;
+                return ret;
+            }
+        }
+
+        final Object[] objectsArray = (Object[]) object;
+
+        @SuppressWarnings("unchecked")
+        final T[] ret = (T[]) Array.newInstance(clazz, objectsArray.length);
+
+        for (int i = 0; i < objectsArray.length; i++) {
+            ret[i] = safeCast(objectsArray[i], clazz);
+            if (ret[i] == null) {
+                // One of the safe casts failed - abort
+                return null;
+            }
+        }
+
+        return ret;
+    }
+
+    private <T> T safeCast(final Object object, final Class<T> clazz) {
+        if (object == null) {
+            return null;
+        }
+        if (clazz.isInstance(object)) {
+            return clazz.cast(object);
+        }
+
+        LOG.error(
+                "Unable to cast {} ({}) to {}, returning null - this is likely a bug. Record: {}",
+                object,
+                object.getClass().getSimpleName(),
+                clazz.getSimpleName(),
+                this
+        );
+
+        return null;
+    }
+
    public Object getFieldByName(String name) {
        for (FieldData fieldData :
                fieldDataList) {
@@ -290,6 +347,7 @@ public class RecordData {
            return fieldDefinition.decode(valueHolder);
        }

+        @NonNull
        public String toString() {
            return "(" + fieldDefinition.getBaseType().name() + "/" + size + ")";
        }
@@ -52,7 +52,7 @@ import nodomain.freeyourgadget.gadgetbridge.util.FileUtils;
@RequiresApi(api = Build.VERSION_CODES.CUR_DEVELOPMENT)
 public class FitCodeGen {
    private static final String COPYRIGHT_HEADER = """
-            /*  Copyright (C) 2025 Freeyourgadget
+            /*  Copyright (C) 2026 Freeyourgadget
            
                This file is part of Gadgetbridge.
            
@@ -126,7 +126,8 @@ public class FitCodeGen {
        final String result = template
                .replace("${copyrightHeader}", (existingHeader.isEmpty() ? COPYRIGHT_HEADER : existingHeader).strip())
                .replace("${generatorClass}", Objects.requireNonNull(getClass().getCanonicalName()))
-                .replace("${switchCases}", String.join("\n", switchCases));
+                .replace("${switchCases}", String.join("\n", switchCases))
+                .replaceAll("\\R", System.lineSeparator());

        FileUtils.copyStringToFile(result, factoryFile, "replace");
    }
@@ -246,18 +247,7 @@ public class FitCodeGen {
                        
                            @Nullable
                            public ${fieldType}[] ${getterName}() {
-                                final Object object = getFieldByNumber(${primitiveNumber});
-                                if (object == null)
-                                    return null;
-                                if (!object.getClass().isArray()) {
-                                    return new ${fieldType}[]{(${fieldType}) object};
-                                }
-                                final Object[] objectsArray = (Object[]) object;
-                                final ${fieldType}[] ret = new ${fieldType}[objectsArray.length];
-                                for (int i = 0; i < objectsArray.length; i++) {
-                                    ret[i] = (${fieldType}) objectsArray[i];
-                                }
-                                return ret;
+                                return getArrayFieldByNumber(${primitiveNumber}, ${fieldType}.class);
                            }
                        """;
            } else {
@@ -266,7 +256,7 @@ public class FitCodeGen {
                        
                            @Nullable
                            public ${fieldType} ${getterName}() {
-                                return (${fieldType}) getFieldByNumber(${primitiveNumber});
+                                return getFieldByNumber(${primitiveNumber}, ${fieldType}.class);
                            }
                        """;
            }
@@ -344,7 +334,9 @@ public class FitCodeGen {
            sb.append("}\n");
        }

-        FileUtils.copyStringToFile(sb.toString(), outputFile, "replace");
+        final String output = sb.toString().replaceAll("\\R", System.lineSeparator());
+
+        FileUtils.copyStringToFile(output, outputFile, "replace");
    }

    public Class<?> getFieldType(final GlobalFITMessage.FieldDefinitionPrimitive primitive) {
@@ -1,3 +0,0 @@
-# nodomain.freeyourgadget.gadgetbridge.service.devices.garmin.fit.codegenFitCodeGen
-# is hard coded to uses \n
-*.java text eol=lf