Feat: Expose sign-from-context, deprecate settings Signer

library/src/androidTest/kotlin/org/contentauth/c2pa/AndroidSignerTests.kt

@@ -105,6 +105,30 @@ class AndroidSignerTests : SignerTests() {
         assertTrue(result.success, "StrongBox Availability test failed: ${result.message}")
     }
 
+    @Test
+    fun runTestSignWithContextFromSettings() = runBlocking {
+        val result = testSignWithContextFromSettings()
+        assertTrue(result.success, "Sign With Context (settings signer) test failed: ${result.message}")
+    }
+
+    @Test
+    fun runTestSignUnsupportedFormat() = runBlocking {
+        val result = testSignUnsupportedFormat()
+        assertTrue(result.success, "Sign Unsupported Format test failed: ${result.message}")
+    }
+
+    @Test
+    fun runTestSignWithContextFromJson() = runBlocking {
+        val result = testSignWithContextFromJson()
+        assertTrue(result.success, "Sign With Context (fromJson builder) test failed: ${result.message}")
+    }
+
+    @Test
+    fun runTestSignWithContextWithoutSigner() = runBlocking {
+        val result = testSignWithContextWithoutSigner()
+        assertTrue(result.success, "Sign With Context (no signer) test failed: ${result.message}")
+    }
+
     @Test
     fun runTestSignerFromSettingsToml() = runBlocking {
         val result = testSignerFromSettingsToml()

library/src/main/jni/c2pa_jni.c

@@ -1034,34 +1034,9 @@ JNIEXPORT jint JNICALL Java_org_contentauth_c2pa_Builder_writeIngredientArchiveN
     return result;
 }
 
-JNIEXPORT jobject JNICALL Java_org_contentauth_c2pa_Builder_signNative(JNIEnv *env, jobject obj, jlong builderPtr, jstring format, jlong sourceStreamPtr, jlong destStreamPtr, jlong signerPtr) {
-    if (builderPtr == 0 || format == NULL || sourceStreamPtr == 0 || destStreamPtr == 0 || signerPtr == 0) {
-        (*env)->ThrowNew(env, (*env)->FindClass(env, "java/lang/IllegalArgumentException"), 
-                         "Builder, format, streams, and signer cannot be null");
-        return NULL;
-    }
-
-    struct C2paBuilder *builder = (struct C2paBuilder*)(uintptr_t)builderPtr;
-    const char *cformat = jstring_to_cstring(env, format);
-    if (cformat == NULL) {
-        return NULL;
-    }
-
-    struct C2paStream *source = (struct C2paStream*)(uintptr_t)sourceStreamPtr;
-    struct C2paStream *dest = (struct C2paStream*)(uintptr_t)destStreamPtr;
-    struct C2paSigner *signer = (struct C2paSigner*)(uintptr_t)signerPtr;
-
-    const unsigned char *manifestBytes = NULL;
-    int64_t size = c2pa_builder_sign(builder, cformat, source, dest, signer, &manifestBytes);
-
-    release_cstring(env, format, cformat);
-
-    if (size < 0) {
-        throw_c2pa_exception(env, "Failed to sign builder");
-        return NULL;
-    }
-
-    // Create result object
+// Builds a Builder.SignResult from a sign call's outputs. Frees manifestBytes on every
+// path; returns NULL (with the pending exception cleared) if construction fails.
+static jobject build_sign_result(JNIEnv *env, int64_t size, const unsigned char *manifestBytes) {
     jclass resultClass = g_signResultClass;
     if (resultClass == NULL) {
         resultClass = (*env)->FindClass(env, "org/contentauth/c2pa/Builder$SignResult");
@@ -1073,7 +1048,7 @@ JNIEXPORT jobject JNICALL Java_org_contentauth_c2pa_Builder_signNative(JNIEnv *e
             return NULL;
         }
     }
-    
+
     jmethodID constructor = (*env)->GetMethodID(env, resultClass, "<init>", "(J[B)V");
     if (constructor == NULL) {
         check_exception(env);
@@ -1082,32 +1057,93 @@ JNIEXPORT jobject JNICALL Java_org_contentauth_c2pa_Builder_signNative(JNIEnv *e
         }
         return NULL;
     }
-    
+
     jbyteArray jmanifestBytes = NULL;
     if (manifestBytes != NULL && size > 0) {
         jmanifestBytes = safe_new_byte_array(env, size);
         if (jmanifestBytes == NULL) {
             c2pa_free(manifestBytes);
             return NULL;
         }
-        
+
         (*env)->SetByteArrayRegion(env, jmanifestBytes, 0, size, (const jbyte*)manifestBytes);
         if (check_exception(env)) {
             c2pa_free(manifestBytes);
             return NULL;
         }
-
+    }
+    if (manifestBytes != NULL) {
         c2pa_free(manifestBytes);
     }
-    
+
     jobject result = (*env)->NewObject(env, resultClass, constructor, (jlong)size, jmanifestBytes);
     if (result == NULL) {
         check_exception(env);
     }
-    
+
     return result;
 }
 
+JNIEXPORT jobject JNICALL Java_org_contentauth_c2pa_Builder_signNative(JNIEnv *env, jobject obj, jlong builderPtr, jstring format, jlong sourceStreamPtr, jlong destStreamPtr, jlong signerPtr) {
+    if (builderPtr == 0 || format == NULL || sourceStreamPtr == 0 || destStreamPtr == 0 || signerPtr == 0) {
+        (*env)->ThrowNew(env, (*env)->FindClass(env, "java/lang/IllegalArgumentException"), 
+                         "Builder, format, streams, and signer cannot be null");
+        return NULL;
+    }
+
+    struct C2paBuilder *builder = (struct C2paBuilder*)(uintptr_t)builderPtr;
+    const char *cformat = jstring_to_cstring(env, format);
+    if (cformat == NULL) {
+        return NULL;
+    }
+
+    struct C2paStream *source = (struct C2paStream*)(uintptr_t)sourceStreamPtr;
+    struct C2paStream *dest = (struct C2paStream*)(uintptr_t)destStreamPtr;
+    struct C2paSigner *signer = (struct C2paSigner*)(uintptr_t)signerPtr;
+
+    const unsigned char *manifestBytes = NULL;
+    int64_t size = c2pa_builder_sign(builder, cformat, source, dest, signer, &manifestBytes);
+
+    release_cstring(env, format, cformat);
+
+    // On failure, return NULL and let the Kotlin wrapper raise C2PAError from c2pa_error().
+    if (size < 0) {
+        return NULL;
+    }
+
+    return build_sign_result(env, size, manifestBytes);
+}
+
+JNIEXPORT jobject JNICALL Java_org_contentauth_c2pa_Builder_signWithContextNative(JNIEnv *env, jobject obj, jlong builderPtr, jstring format, jlong sourceStreamPtr, jlong destStreamPtr) {
+    if (builderPtr == 0 || format == NULL || sourceStreamPtr == 0 || destStreamPtr == 0) {
+        (*env)->ThrowNew(env, (*env)->FindClass(env, "java/lang/IllegalArgumentException"),
+                         "Builder, format, and streams cannot be null");
+        return NULL;
+    }
+
+    struct C2paBuilder *builder = (struct C2paBuilder*)(uintptr_t)builderPtr;
+    const char *cformat = jstring_to_cstring(env, format);
+    if (cformat == NULL) {
+        return NULL;
+    }
+
+    struct C2paStream *source = (struct C2paStream*)(uintptr_t)sourceStreamPtr;
+    struct C2paStream *dest = (struct C2paStream*)(uintptr_t)destStreamPtr;
+
+    // Signer comes from the builder's context (programmatic or from settings).
+    const unsigned char *manifestBytes = NULL;
+    int64_t size = c2pa_builder_sign_context(builder, cformat, source, dest, &manifestBytes);
+
+    release_cstring(env, format, cformat);
+
+    // On failure, return NULL and let the Kotlin wrapper raise C2PAError from c2pa_error().
+    if (size < 0) {
+        return NULL;
+    }
+
+    return build_sign_result(env, size, manifestBytes);
+}
+
 // New Builder methods
 JNIEXPORT jbyteArray JNICALL Java_org_contentauth_c2pa_Builder_dataHashedPlaceholderNative(JNIEnv *env, jobject obj, jlong builderPtr, jlong reservedSize, jstring format) {
     if (builderPtr == 0 || format == NULL || reservedSize <= 0) {

library/src/main/kotlin/org/contentauth/c2pa/Builder.kt

@@ -576,13 +576,30 @@ class Builder internal constructor(private var ptr: Long) : Closeable {
      * @throws C2PAError.Api if signing fails
      */
     @Throws(C2PAError::class)
-    fun sign(format: String, source: Stream, dest: Stream, signer: Signer): SignResult {
-        val result = signNative(ptr, format, source.rawPtr, dest.rawPtr, signer.ptr)
-        if (result.size < 0) {
-            throw C2PAError.Api(C2PA.getError() ?: "Failed to sign")
-        }
-        return result
-    }
+    fun sign(format: String, source: Stream, dest: Stream, signer: Signer): SignResult =
+        signNative(ptr, format, source.rawPtr, dest.rawPtr, signer.ptr)
+            ?: throw C2PAError.Api(C2PA.getError() ?: "Failed to sign")
+
+    /**
+     * Signs the manifest using the signer configured on the builder's [C2PAContext] — either set
+     * programmatically (`C2PAContextBuilder.setSigner`) or supplied via settings (`[signer.local]`
+     * / `[cawg_x509_signer]`) — and writes the signed asset to [dest].
+     *
+     * Unlike [sign], no explicit [Signer] is passed; the builder's context must have a signer
+     * configured, or signing fails. Every builder has a context ([fromJson] creates one
+     * internally), so this also works for builders created with [fromJson] and a [C2PASettings]
+     * that carries a signer. Use this instead of the deprecated settings-based [Signer] factories.
+     *
+     * @param format The MIME type of the asset (e.g. "image/jpeg")
+     * @param source The input stream containing the original asset
+     * @param dest The output stream for the signed asset
+     * @return A [SignResult] containing the manifest size and optional manifest bytes
+     * @throws C2PAError.Api if signing fails (e.g. the context has no signer)
+     */
+    @Throws(C2PAError::class)
+    fun signWithContext(format: String, source: Stream, dest: Stream): SignResult =
+        signWithContextNative(ptr, format, source.rawPtr, dest.rawPtr)
+            ?: throw C2PAError.Api(C2PA.getError() ?: "Failed to sign with context")
 
     /**
      * Creates a data-hashed placeholder for deferred signing workflows.
@@ -815,7 +832,13 @@ class Builder internal constructor(private var ptr: Long) : Closeable {
         sourceHandle: Long,
         destHandle: Long,
         signerHandle: Long,
-    ): SignResult
+    ): SignResult?
+    private external fun signWithContextNative(
+        handle: Long,
+        format: String,
+        sourceHandle: Long,
+        destHandle: Long,
+    ): SignResult?
     private external fun dataHashedPlaceholderNative(handle: Long, reservedSize: Long, format: String): ByteArray?
     private external fun signDataHashedEmbeddableNative(
         handle: Long,

library/src/main/kotlin/org/contentauth/c2pa/C2PA.kt

@@ -44,12 +44,20 @@ object C2PA {
      * Load settings from a string.
      * Returns the result code from the native call (0 for success).
      */
+    @Deprecated(
+        "Global settings apply relies on the deprecated c2pa_load_settings. Configure settings " +
+            "in C2PASettings and build a C2PAContext instead.",
+    )
     @JvmStatic
     fun loadSettingsResult(settings: String, format: String): Int = loadSettingsNative(settings, format)
 
     /**
      * Load settings from a string
      */
+    @Deprecated(
+        "Global settings apply relies on the deprecated c2pa_load_settings. Configure settings " +
+            "in C2PASettings and build a C2PAContext instead.",
+    )
     @Throws(C2PAError::class)
     fun loadSettings(settings: String, format: String) {
         executeC2PAOperation("Failed to load settings") {

library/src/main/kotlin/org/contentauth/c2pa/Signer.kt

@@ -116,6 +116,11 @@ class Signer internal constructor(internal var ptr: Long) : Closeable {
          * }
          * ```
          */
+        @Deprecated(
+            "Settings-based signers rely on deprecated core APIs (c2pa_load_settings / " +
+                "c2pa_signer_from_settings). Configure the signer in C2PASettings, build a " +
+                "C2PAContext, and sign via Builder.signWithContext().",
+        )
         @JvmStatic
         @Throws(C2PAError::class)
         fun fromSettingsJson(settingsJson: String): Signer = fromSettings(settingsJson, "json")
@@ -161,6 +166,11 @@ class Signer internal constructor(internal var ptr: Long) : Closeable {
          * referenced_assertions = ["cawg.training-mining"]
          * ```
          */
+        @Deprecated(
+            "Settings-based signers rely on deprecated core APIs (c2pa_load_settings / " +
+                "c2pa_signer_from_settings). Configure the signer in C2PASettings, build a " +
+                "C2PAContext, and sign via Builder.signWithContext().",
+        )
         @JvmStatic
         @Throws(C2PAError::class)
         fun fromSettingsToml(settingsToml: String): Signer = fromSettings(settingsToml, "toml")
@@ -173,6 +183,7 @@ class Signer internal constructor(internal var ptr: Long) : Closeable {
          * @return A new [Signer] instance configured according to the settings.
          * @throws C2PAError if the settings are invalid or the signer cannot be created.
          */
+        @Suppress("DEPRECATION")
         @JvmStatic
         @Throws(C2PAError::class)
         private fun fromSettings(settings: String, format: String): Signer =
@@ -195,6 +206,11 @@ class Signer internal constructor(internal var ptr: Long) : Closeable {
          * @param format The format of the settings string ("json" or "toml").
          * @throws C2PAError if the settings are invalid.
          */
+        @Deprecated(
+            "Global settings apply relies on the deprecated c2pa_load_settings. Configure settings " +
+                "in C2PASettings and build a C2PAContext instead.",
+        )
+        @Suppress("DEPRECATION")
         @JvmStatic
         @Throws(C2PAError::class)
         fun loadSettings(settings: String, format: String) {

test-app/app/src/main/kotlin/org/contentauth/c2pa/testapp/TestScreen.kt

@@ -225,6 +225,10 @@ private suspend fun runAllTests(context: Context): List<TestResult> = withContex
     results.add(signerTests.testStrongBoxSignerIntegration())
     results.add(signerTests.testKeyStoreSignerKeyManagement())
     results.add(signerTests.testStrongBoxAvailability())
+    results.add(signerTests.testSignUnsupportedFormat())
+    results.add(signerTests.testSignWithContextFromSettings())
+    results.add(signerTests.testSignWithContextFromJson())
+    results.add(signerTests.testSignWithContextWithoutSigner())
     results.add(signerTests.testSignerFromSettingsToml())
     results.add(signerTests.testSignerFromSettingsJson())
     results.add(signerTests.testCawgCombinedPemSigner())

test-shared/src/main/kotlin/org/contentauth/c2pa/test/shared/CoreTests.kt

@@ -332,6 +332,7 @@ abstract class CoreTests : TestBase() {
         }
     }
 
+    @Suppress("DEPRECATION")
     suspend fun testLoadSettings(): TestResult = withContext(Dispatchers.IO) {
         runTest("Load Settings") {
             val settingsJson =