Add golden tests to the current OpenID4VP matcher

matcher/.gitignore

@@ -0,0 +1,2 @@
+test_runner
+*.o

matcher/Makefile

@@ -0,0 +1,37 @@
+CXX = g++
+CC = gcc
+CXXFLAGS = -std=c++17 -Wall -Wextra -g -I. -I/usr/include/doctest -I/usr/include/nlohmann
+CFLAGS = -Wall -Wextra -g -I. -Wno-unused-variable -Wno-unused-but-set-variable -Wno-format-overflow
+
+# Common objects
+COMMON_OBJS = dcql.o openid4vp1_0.o base64.o cJSON/cJSON.o issuance/provision.o
+
+# Tests
+test_runner: test_runner.o dcql.o openid4vp1_0.o base64.o cJSON/cJSON.o
+	$(CXX) $(CXXFLAGS) -o $@ $^
+
+test: test_runner
+	./test_runner
+
+test_runner.o: test_runner.cc
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+dcql.o: dcql.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+openid4vp1_0.o: openid4vp1_0.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+base64.o: base64.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+cJSON/cJSON.o: cJSON/cJSON.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+issuance/provision.o: issuance/provision.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -f *.o cJSON/*.o issuance/*.o test_runner
+
+.PHONY: test clean

matcher/base64.c

@@ -43,6 +43,7 @@ int B64DecodeURL(char* input, char** output) {
         output_len--;
     }
 
+    buffer[output_len] = '\0';
 
     return output_len;
 }

matcher/index.md

@@ -0,0 +1,117 @@
+# OpenID4VP Matcher: Comprehensive Code Index
+
+## 1. Registry Binary Format
+The registry blob is a custom binary format:
+- **Header**: 4 bytes (Little-endian `int`) representing the offset from the start of the blob to the beginning of the JSON metadata.
+- **Icon Section**: Raw PNG bytes located between the header and the JSON metadata.
+- **Metadata Section**: UTF-8 encoded JSON string starting at the specified offset.
+
+## 2. Registry JSON Schema
+Root structure: `{"credentials": { ... }}`
+
+### 2.1 mso_mdoc (credentials.mso_mdoc)
+- **Key**: Document Type (e.g., "org.iso.18013.5.1.mDL")
+- **Value**: Array of Credential Objects:
+  - `id`: String.
+  - `display`:
+    - `verification`:
+      - `title`: String.
+      - `subtitle`: String (optional).
+      - `explainer`: String (optional).
+      - `warning`: String (optional).
+      - `metadata_display_text`: String (optional).
+      - `icon`: `{"start": <int>, "length": <int>}`.
+  - `paths`: Map of Namespace -> Map of ClaimName -> Claim object:
+    - `value`: Any (raw value).
+    - `display`:
+      - `verification`:
+        - `display`: String (localized name).
+        - `display_value`: String (optional localized value).
+
+### 2.2 dc+sd-jwt (credentials.dc+sd-jwt)
+- **Key**: Verifiable Credential Type (VCT) string.
+- **Value**: Array of Credential Objects.
+- **Paths Construction**: The Kotlin `SdJwtEntry.claims` (a list) is flattened into a nested `paths` object. Each `SdJwtClaim.path` (an array of strings) defines the nesting.
+- **Example**: A claim with `path = ["user", "name", "first"]` becomes:
+  ```json
+  "paths": {
+    "user": {
+      "name": {
+        "first": {
+          "value": "John",
+          "display": { "verification": { "display": "First Name", ... } }
+        }
+      }
+    }
+  }
+  ```
+- **Structure**:
+  - `id`: String.
+  - `display`: (same as mso_mdoc).
+  - `paths`: Recursive nested object. Leaf nodes are Claim objects (same structure as mso_mdoc).
+
+### 2.3 Issuance (credentials.issuance)
+- **mso_mdoc**: Array of MdocInlineIssuanceEntry objects:
+  - `id`: String.
+  - `subtitle`: String (optional).
+  - `title`: String (optional hint).
+  - `icon`: `{"start": <int>, "length": <int>}` (optional).
+  - `supported`: Array of DocType Strings.
+- **dc+sd-jwt**: Array of SdJwtInlineIssuanceEntry objects:
+  - `id`: String.
+  - `subtitle`: String (optional).
+  - `title`: String (optional hint).
+  - `icon`: `{"start": <int>, "length": <int>}` (optional).
+  - `supported`: Array of VCT Strings.
+
+---
+
+## 3. C Function Index
+
+### base64.c / base64.h
+- `static int B64Lookup(char x)`: Helper function that maps Base64-URL characters to their corresponding 6-bit integer values.
+- `int B64DecodeURL(char* input, char** output)`: Takes a Base64-URL encoded string and decodes it. It allocates a new buffer for the output using `malloc` and returns the decoded length. It correctly handles base64url specific characters ('-' and '_') as well as standard padding ('=').
+
+### credentialmanager.c / credentialmanager.h
+- Provides ACM (Android Credential Manager) environment bindings to interface with the Android OS.
+- `void* GetRequest()`: Fetches the buffer containing the ACM request JSON.
+- `void* GetCredentials()`: Fetches the buffer containing the Registry binary blob.
+- Also exposes WASM imports for ACM reporting: `AddEntrySet`, `AddEntryToSet`, `AddFieldToEntrySet`, `AddPaymentEntryToSetV2`, `GetWasmVersion`, `AddInlineIssuanceEntry`, etc.
+
+### dcql.c / dcql.h
+- `int AddAllClaims(cJSON* matched_claim_names, cJSON* candidate_paths)`: Recursively traverses a JSON object representing candidate claim paths. For every object containing a "display" key, it adds that "display" object to the `matched_claim_names` array. This is used when a request doesn't specify specific claims, so the matcher must collect all available claims from the credential to show to the user.
+- `cJSON* MatchCredential(cJSON* credential, cJSON* credential_store)`: Evaluates a single DCQL `credential` requirement against the registry `credential_store`.
+  - Determines if the requested format is `mso_mdoc` or `dc+sd-jwt`.
+  - Checks if the credential candidate matches the `meta` criteria (e.g., matching `doctype_value` for `mso_mdoc`, or `vct_values` for `dc+sd-jwt`).
+  - Iterates over candidates that matched the `meta` criteria.
+  - If specific `claims` are requested, it traverses the `paths` of the candidate using the requested JSON paths array. It matches claim values if `values` are specified in the request.
+  - If `claim_sets` are specified, it verifies that at least one logical group of claims is fully satisfied by the matched claims.
+  - Identifies matching inline issuance options by comparing `supported` DocTypes or VCTs against the `meta` requirements.
+  - Returns a JSON object with `matched_creds` (list of matched credentials containing `id`, `display`, `matched_claim_names`, and `matched_claim_metadata`) and an `inline_issuance` entry if applicable.
+- `cJSON* dcql_query(cJSON* query, cJSON* credential_store)`: High-level function that orchestrates DCQL evaluation.
+  - Iterates over all `credentials` in the DCQL query and calls `MatchCredential` for each.
+  - If `credential_sets` are defined in the query, it iterates over these sets and their options to find valid combinations of matched credentials that satisfy the query logic (handling `required` flags).
+  - If no `credential_sets` are defined, it requires all requested credentials to match.
+  - Returns a final `match_result` JSON containing `matched_credential_sets` (valid combinations of credentials) and `matched_credentials` (the actual credential details).
+
+### openid4vp1_0.c
+- `void report_credential_set_length(...)`: Recursively calculates the total number of credentials across all options in a matched credential set and reports this total length to the ACM using `AddEntrySet`.
+- `void report_matched_credential(...)`: Reports a specific matched credential to the ACM.
+  - Constructs a JSON metadata string containing the matched claims, request index, and DCQL IDs.
+  - Checks if the credential is a payment transaction (if `transaction_credential_ids` match). If so, it reports it as a payment entry via `AddPaymentEntryToSetV2` or `AddPaymentEntryToSet` (depending on the WASM version).
+  - Otherwise, it reports it as a standard entry via `AddEntryToSet`, providing title, subtitle, explainer, and icon offsets.
+  - Iterates through `matched_claim_names` to report each individual matched claim via `AddFieldToEntrySet`.
+  - Reports `metadata_display_text` via `AddMetadataDisplayTextToEntrySet` if present.
+- `void report_matched_credential_set(...)`: Recursively iterates through the complex `matched_credential_sets` structure returned by `dcql_query` and calls `report_matched_credential` for each valid credential in each option.
+- `int main()`: The global entry point for the WASM module.
+  - Fetches the credentials binary blob and finds the JSON metadata offset.
+  - Parses the registry JSON and the DCQL request JSON.
+  - Determines if the request is OpenID4VP (signed or unsigned) and decodes the payload via `B64DecodeURL` if it's signed (JWS).
+  - Handles transaction data extraction for payments (merchant name, amount, additional info).
+  - Calls `dcql_query` to perform the actual matching.
+  - Extracts the matched results and uses the `report_*` functions to format and send the results back to the Android OS via the ACM API.
+  - Handles inline issuance fallback by calling `AddInlineIssuanceEntry` if no regular credentials match but inline issuance is supported.
+
+### testharness.c
+- Provides mock implementations for ACM APIs (`GetRequestSize`, `GetRequestBuffer`, `GetCredentialsSize`, `ReadCredentialsBuffer`, etc.) to allow for local execution of the `main()` function.
+- Reads test inputs from local files like `request.json` and `testcreds.json`.

matcher/openid4vp1_0.c

@@ -163,7 +163,7 @@ void report_matched_credential(uint32_t wasm_version, cJSON* matched_doc, cJSON*
                     AddFieldForStringIdEntry(id, claim_display, claim_value);
                 }
             }
-            if (wasm_version >= 5) {
+            if (wasm_version >= 5 && metadata_display_text != NULL) {
                 AddMetadataDisplayTextToEntrySet(matched_id, metadata_display_text, set_id, doc_idx);
             }
         }
@@ -195,7 +195,7 @@ void report_matched_credential_set(char* set_id, int curr_set_idx, cJSON *matche
     }
 }
 
-int main()
+int openid4vp_main()
 {
     uint32_t credentials_size;
     GetCredentialsSize(&credentials_size);
@@ -298,7 +298,7 @@ int main()
                     transaction_data = cJSON_Parse(transaction_data_json);
                     transaction_credential_ids = cJSON_GetObjectItem(transaction_data, "credential_ids");
                     char *transaction_data_type = cJSON_GetStringValue(cJSON_GetObjectItem(transaction_data, "type"));
-                    if (strcmp(transaction_data_type, "urn:eudi:sca:payment:1") == 0) {
+                    if (transaction_data_type != NULL && strcmp(transaction_data_type, "urn:eudi:sca:payment:1") == 0) {
                         cJSON *payload = cJSON_GetObjectItem(transaction_data, "payload");
                         merchant_name = cJSON_GetStringValue(cJSON_GetObjectItem(cJSON_GetObjectItem(payload, "payee"), "name"));
 
@@ -316,7 +316,7 @@ int main()
                         printf("transaction amount %s\n", transaction_amount);
 
                         additional_info = cJSON_GetStringValue(cJSON_GetObjectItem(transaction_data, "additional_info"));
-                    } else if (strcmp(transaction_data_type, "payment_details") == 0) {
+                    } else if (transaction_data_type != NULL && strcmp(transaction_data_type, "payment_details") == 0) {
                         merchant_name = cJSON_GetStringValue(cJSON_GetObjectItem(transaction_data, "payee_name"));
 
                         char *amount = cJSON_GetStringValue(cJSON_GetObjectItem(transaction_data, "payment_amount"));
@@ -347,7 +347,7 @@ int main()
                 cJSON_ArrayForEach(matched_option, first_matched_credential_set) {
                     cJSON *matched_credential_ids = cJSON_GetObjectItemCaseSensitive(matched_option, "matched_credential_ids");
                     int credential_set_size = cJSON_GetArraySize(matched_credential_ids);
-                    char set_id_buffer[26];
+                    char set_id_buffer[64];
 
                     if (cJSON_HasObjectItem(matched_option, "set_id")) {
                         char *set_idx = cJSON_GetStringValue(cJSON_GetObjectItemCaseSensitive(matched_option, "set_id"));