Feature/c api

src/metkit/CMakeLists.txt

@@ -4,7 +4,6 @@ ecbuild_generate_config_headers( DESTINATION ${INSTALL_INCLUDE_DIR}/metkit )
 
 configure_file( metkit_config.h.in    metkit_config.h )
 configure_file( metkit_version.h.in   metkit_version.h )
-configure_file( metkit_version.cc.in  metkit_version.cc )
 
 install(FILES
             ${CMAKE_CURRENT_BINARY_DIR}/metkit_config.h
@@ -15,7 +14,6 @@ install(FILES
 ### metkit sources
 
 list( APPEND metkit_srcs
-    ${CMAKE_CURRENT_BINARY_DIR}/metkit_version.cc
     config/LibMetkit.cc
     config/LibMetkit.h
     mars/BaseProtocol.cc
@@ -100,6 +98,8 @@ list( APPEND metkit_srcs
     hypercube/HyperCube.cc
     hypercube/HyperCube.h
     hypercube/HyperCubePayloaded.h
+    api/metkit_c.cc 
+    api/metkit_c.h
 )
 
 list( APPEND metkit_persistent_srcs

src/metkit/api/metkit_c.cc

@@ -0,0 +1,348 @@
+#include "metkit_c.h"
+#include "metkit/mars/MarsExpension.h"
+#include "metkit/mars/MarsRequest.h"
+#include "metkit/metkit_version.h"
+
+#include "eckit/exception/Exceptions.h"
+#include "eckit/runtime/Main.h"
+#include "eckit/utils/Optional.h"
+
+#include <functional>
+
+extern "C" {
+
+// ---------------------------------------------------------------------------------------------------------------------
+
+struct metkit_marsrequest_t : public metkit::mars::MarsRequest {
+    using metkit::mars::MarsRequest::MarsRequest;
+
+    metkit_marsrequest_t(metkit::mars::MarsRequest&& k) :
+        metkit::mars::MarsRequest(std::move(k)) {}
+};
+
+struct metkit_requestiterator_t {
+    metkit_requestiterator_t(std::vector<metkit::mars::MarsRequest>&& vec) :
+        vector_(std::move(vec)), iterator_(vector_.begin()) {}
+
+    int next() {
+        if (iterator_ == vector_.end()) {
+            return METKIT_ITERATION_COMPLETE;
+        }
+        ++iterator_;
+        return iterator_ == vector_.end() ? METKIT_ITERATION_COMPLETE : METKIT_SUCCESS;
+    }
+
+    void current(metkit_marsrequest_t* request)  {
+        ASSERT(iterator_ != vector_.end());
+        *request = std::move(*iterator_);
+    }
+
+private:
+
+    std::vector<metkit::mars::MarsRequest> vector_;
+    std::vector<metkit::mars::MarsRequest>::iterator iterator_;
+};
+
+/// @comment: (maby)
+/// Not sure if there is much value in having a param iterator. We could just return an array of
+/// strings (char**) using metkit_marsrequest_params.
+/// I think we should metkit_paramiterator_t.
+struct metkit_paramiterator_t {
+    metkit_paramiterator_t(std::vector<std::string> vec) :
+        vector_(std::move(vec)), iterator_(vector_.begin()) {}
+
+    int next() {
+        if (iterator_ == vector_.end()) {
+            return METKIT_ITERATION_COMPLETE;
+        }
+        ++iterator_;
+
+        return iterator_ == vector_.end() ? METKIT_ITERATION_COMPLETE : METKIT_SUCCESS;
+    }
+
+    void current(const char** param) {
+        ASSERT(iterator_ != vector_.end());
+        *param = iterator_->c_str();
+    }
+
+private: 
+    std::vector<std::string> vector_;
+    std::vector<std::string>::iterator iterator_;
+};
+
+// ---------------------------------------------------------------------------------------------------------------------
+//                           ERROR HANDLING
+
+}  // extern "C"
+
+static thread_local std::string g_current_error_string;
+
+const char* metkit_get_error_string(int) {
+    return g_current_error_string.c_str();
+}
+
+int innerWrapFn(std::function<int()> f) {
+    return f();
+}
+
+int innerWrapFn(std::function<void()> f) {
+    f();
+    return METKIT_SUCCESS;
+}
+
+template <typename FN>
+[[nodiscard]] int tryCatch(FN&& fn) {
+    try {
+        return innerWrapFn(fn);
+    }
+    catch (const eckit::UserError& e) {
+        eckit::Log::error() << "User Error: " << e.what() << std::endl;
+        g_current_error_string = e.what();
+        return METKIT_ERROR_USER;
+    }
+    catch (const eckit::AssertionFailed& e) {
+        eckit::Log::error() << "Assertion Failed: " << e.what() << std::endl;
+        g_current_error_string = e.what();
+        return METKIT_ERROR_ASSERT;
+    }
+    catch (const eckit::Exception& e) {
+        eckit::Log::error() << "METKIT Error: " << e.what() << std::endl;
+        g_current_error_string = e.what();
+        return METKIT_ERROR;
+    }
+    catch (const std::exception& e) {
+        eckit::Log::error() << "Unknown Error: " << e.what() << std::endl;
+        g_current_error_string = e.what();
+        return METKIT_ERROR_UNKNOWN;
+    }
+    catch (...) {
+        eckit::Log::error() << "Unknown Error!" << std::endl;
+        g_current_error_string = "<unknown>";
+        return METKIT_ERROR_UNKNOWN;
+    }
+}
+
+extern "C" {
+
+// -----------------------------------------------------------------------------
+//                           HELPERS
+// -----------------------------------------------------------------------------
+
+int metkit_version(const char** version) {
+    *version = metkit_version_str();
+    return METKIT_SUCCESS;
+}
+
+int metkit_vcs_version(const char** sha1) {
+    *sha1 = metkit_git_sha1();
+    return METKIT_SUCCESS;
+}
+
+int metkit_initialise() {
+    return tryCatch([] {
+        static bool initialised = false;
+
+        if (initialised) {
+            eckit::Log::warning()
+                << "Initialising Metkit library twice" << std::endl;
+        }
+
+        if (!initialised) {
+            const char* argv[2] = {"metkit-api", 0};
+            eckit::Main::initialise(1, const_cast<char**>(argv));
+            initialised = true;
+        }
+    });
+}
+
+// -----------------------------------------------------------------------------
+//                           PARSING
+// -----------------------------------------------------------------------------
+
+int metkit_parse_marsrequest(const char* str, metkit_requestiterator_t** requests, bool strict) {
+    return tryCatch([requests, str, strict] {
+        ASSERT(requests);
+        ASSERT(str);
+        std::istringstream in(str);
+        *requests = new metkit_requestiterator_t(metkit::mars::MarsRequest::parse(in, strict));
+    });
+}
+
+// -----------------------------------------------------------------------------
+//                           REQUEST
+// -----------------------------------------------------------------------------
+
+int metkit_new_marsrequest(metkit_marsrequest_t** request) {
+    return tryCatch([request] {
+        ASSERT(request);
+        *request = new metkit_marsrequest_t();
+    });
+}
+
+int metkit_free_marsrequest(const metkit_marsrequest_t* request) {
+    return tryCatch([request] {
+        ASSERT(request);
+        delete request;
+    });
+}   
+
+int metkit_marsrequest_add(metkit_marsrequest_t* request, const char* param, const char* values[], int numValues) {
+    return tryCatch([request, param, values, numValues] {
+        ASSERT(request);
+        ASSERT(param);
+        ASSERT(values);
+        std::string n(param);
+        std::vector<std::string> vv;
+        for (int i = 0; i < numValues; i++) {
+            vv.push_back(std::string(values[i]));
+        }
+        request->values(n, vv);
+    });
+}
+
+int metkit_marsrequest_add1(metkit_marsrequest_t* request, const char* param, const char* value) {
+    return metkit_marsrequest_add(request, param, &value, 1);
+}
+
+int metkit_marsrequest_set_verb(metkit_marsrequest_t* request, const char* verb) {
+    return tryCatch([request, verb] {
+        ASSERT(request);
+        ASSERT(verb);
+        request->verb(verb);
+    });
+}
+
+int metkit_marsrequest_verb(const metkit_marsrequest_t* request, const char** verb) {
+    return tryCatch([request, verb] {
+        ASSERT(request);
+        ASSERT(verb);
+        *verb = request->verb().c_str();
+    });
+}
+
+int metkit_marsrequest_has_param(const metkit_marsrequest_t* request, const char* param, bool* has) {
+    return tryCatch([request, param, has] {
+        ASSERT(request);
+        ASSERT(param);
+        ASSERT(has);
+        *has = request->has(param);
+    });
+}
+
+int metkit_marsrequest_params(const metkit_marsrequest_t* request, metkit_paramiterator_t** params) {
+    return tryCatch([request, params] {
+        ASSERT(request);
+        ASSERT(params);
+        *params = new metkit_paramiterator_t(request->params());
+    });
+}
+
+int metkit_marsrequest_count_values(const metkit_marsrequest_t* request, const char* param, size_t* count) {
+    return tryCatch([request, param, count] {
+        ASSERT(request);
+        ASSERT(param);
+        ASSERT(count);
+        *count = request->countValues(param);
+    });
+}
+
+int metkit_marsrequest_value(const metkit_marsrequest_t* request, const char* param, int index, const char** value) {
+    return tryCatch([request, param, index, value] {
+        ASSERT(request);
+        ASSERT(param);
+        ASSERT(value);
+        *value = (request->values(param, false))[index].c_str();
+    });
+}
+
+int metkit_marsrequest_values(const metkit_marsrequest_t* request, const char* param, const char** values[], size_t* numValues) {
+    return tryCatch([request, param, values, numValues] {
+        ASSERT(request);
+        ASSERT(param);
+        ASSERT(values);
+        ASSERT(numValues);
+        const std::vector<std::string>& v = request->values(param);
+        *numValues = v.size();
+        *values = new const char*[v.size()];
+        for (size_t i = 0; i < v.size(); i++) {
+            (*values)[i] = v[i].c_str();
+        }
+    });
+}
+
+int metkit_marsrequest_expand(const metkit_marsrequest_t* request, metkit_marsrequest_t* expandedRequest, bool inherit, bool strict) {
+    return tryCatch([request, expandedRequest, inherit, strict] {
+        ASSERT(request);
+        ASSERT(expandedRequest);
+        ASSERT(expandedRequest->empty());
+        metkit::mars::MarsExpension expand(inherit, strict);
+        *expandedRequest = expand.expand(*request);
+    });
+}
+
+int metkit_marsrequest_merge(metkit_marsrequest_t* request, const metkit_marsrequest_t* otherRequest) {
+    return tryCatch([request, otherRequest] {
+        ASSERT(request);
+        ASSERT(otherRequest);
+        request->merge(*otherRequest);
+    });
+}
+
+// -----------------------------------------------------------------------------
+//                           REQUEST ITERATOR
+// -----------------------------------------------------------------------------
+
+int metkit_free_requestiterator(const metkit_requestiterator_t* it) {
+    return tryCatch([it] {
+        ASSERT(it);
+        delete it;
+    });
+}
+
+int metkit_requestiterator_next(metkit_requestiterator_t* it) {
+    return tryCatch(std::function<int()>{[it] {
+        ASSERT(it);
+        return it->next();
+    }});
+}
+
+int metkit_requestiterator_request(metkit_requestiterator_t* it, metkit_marsrequest_t* request) {
+    return tryCatch([it, request] {
+        ASSERT(it);
+        ASSERT(request);
+        ASSERT(request->empty());
+
+        it->current(request);
+    });
+}
+
+// -----------------------------------------------------------------------------
+//                           PARAM ITERATOR
+// -----------------------------------------------------------------------------
+
+int metkit_free_paramiterator(const metkit_paramiterator_t* it) {
+    return tryCatch([it] {
+        ASSERT(it);
+        delete it;
+    });
+}
+
+int metkit_paramiterator_next(metkit_paramiterator_t* it) {
+    return tryCatch(std::function<int()>{[it] {
+        ASSERT(it);
+        return it->next();
+    }});
+}
+
+int metkit_paramiterator_param(metkit_paramiterator_t* it, const char** param) {
+    return tryCatch([it, param] {
+        ASSERT(it);
+        ASSERT(param);
+        it->current(param);
+    });
+}
+
+
+// ---------------------------------------------------------------------------------------------------------------------
+
+}  // extern "C"