diff options
Diffstat (limited to 'datastore/src/carquinyol/metadatareader.c')
| -rw-r--r-- | datastore/src/carquinyol/metadatareader.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/datastore/src/carquinyol/metadatareader.c b/datastore/src/carquinyol/metadatareader.c new file mode 100644 index 0000000..454c8c3 --- /dev/null +++ b/datastore/src/carquinyol/metadatareader.c @@ -0,0 +1,233 @@ +#include "Python.h" + +#include <dirent.h> + +// TODO: put it in a place where python can use it when writing metadata +#define MAX_PROPERTY_LENGTH 500 * 1024 + +static PyObject *byte_array_type = NULL; + +int +add_property(const char *metadata_path, char *property_name, PyObject *dict, + int must_exist) +{ + int file_path_size; + char *file_path = NULL; + FILE *file = NULL; + long file_size; + char *value_buf = NULL; + PyObject *value = NULL; + struct stat file_stat; + + // Build path of the property file + file_path_size = strlen(metadata_path) + 1 + strlen(property_name) + 1; + file_path = PyMem_Malloc(file_path_size); + if (file_path == NULL) { + PyErr_NoMemory(); + return 0; + } + snprintf (file_path, file_path_size, "%s/%s", metadata_path, property_name); + + if ((!must_exist) && (stat(file_path, &file_stat) != 0)) { + PyMem_Free(file_path); + return 1; + } + + file = fopen(file_path, "r"); + if (file == NULL) { + char buf[256]; + snprintf(buf, sizeof(buf), "Cannot open property file %s: %s", + file_path, strerror(errno)); + PyErr_SetString(PyExc_IOError, buf); + goto cleanup; + } + + // Get file size + fseek (file, 0, SEEK_END); + file_size = ftell (file); + rewind (file); + + if (file_size == 0) { + // Empty property + fclose(file); + file = NULL; + + value = PyString_FromString(""); + if (value == NULL) { + PyErr_SetString(PyExc_ValueError, + "Failed to convert value to python string"); + goto cleanup; + } + } else { + if (file_size > MAX_PROPERTY_LENGTH) { + PyErr_SetString(PyExc_ValueError, "Property file too big"); + goto cleanup; + } + + // Read the whole file + value_buf = PyMem_Malloc(file_size); + if (value_buf == NULL) { + PyErr_NoMemory(); + goto cleanup; + } + long read_size = fread(value_buf, 1, file_size, file); + if (read_size < file_size) { + char buf[256]; + snprintf(buf, sizeof(buf), + "Error while reading property file %s", file_path); + PyErr_SetString(PyExc_IOError, buf); + goto cleanup; + } + + fclose(file); + file = NULL; + + // Convert value to dbus.ByteArray + PyObject *args = Py_BuildValue("(s#)", value_buf, file_size); + + PyMem_Free(value_buf); + value_buf = NULL; + + value = PyObject_CallObject(byte_array_type, args); + Py_DECREF(args); + + if (value == NULL) { + PyErr_SetString(PyExc_ValueError, + "Failed to convert value to dbus.ByteArray"); + goto cleanup; + } + } + + // Add property to the metadata dict + if (PyDict_SetItemString(dict, property_name, value) == -1) { + PyErr_SetString(PyExc_ValueError, + "Failed to add property to dictionary"); + goto cleanup; + } + + Py_DECREF(value); + PyMem_Free(file_path); + + return 1; + +cleanup: + if (file_path) { + PyMem_Free(file_path); + } + if (value_buf) { + PyMem_Free(value_buf); + } + if (file) { + fclose(file); + } + if (value) { + Py_DECREF(value); + } + return 0; +} + +static PyObject * +read_from_properties_list (const char *metadata_path, PyObject *properties) +{ + PyObject *dict = PyDict_New(); + + int i; + for (i = 0; i < PyList_Size(properties); i++) { + PyObject *property = PyList_GetItem(properties, i); + char *property_name = PyString_AsString (property); + + if (add_property(metadata_path, property_name, dict, 0) == 0) + goto cleanup; + } + + return dict; + +cleanup: + if (dict) { + Py_DECREF(dict); + } + return NULL; +} + +static PyObject * +read_all_properties (const char *metadata_path) +{ + PyObject *dict = PyDict_New(); + DIR *dir_stream = NULL; + struct dirent *dir_entry = NULL; + + dir_stream = opendir (metadata_path); + if (dir_stream == NULL) { + char buf[256]; + snprintf(buf, sizeof(buf), "Couldn't open metadata directory %s", + metadata_path); + PyErr_SetString(PyExc_IOError, buf); + goto cleanup; + } + + dir_entry = readdir(dir_stream); + while (dir_entry != NULL) { + // Skip . and .. + if (dir_entry->d_name[0] == '.' && + (strlen(dir_entry->d_name) == 1 || + (dir_entry->d_name[1] == '.' && + strlen(dir_entry->d_name) == 2))) + goto next_property; + + if (add_property(metadata_path, dir_entry->d_name, dict, 1) == 0) + goto cleanup; + + next_property: + dir_entry = readdir(dir_stream); + } + + closedir(dir_stream); + + return dict; + +cleanup: + if (dict) { + Py_DECREF(dict); + } + if (dir_stream) { + closedir(dir_stream); + } + return NULL; +} + +static PyObject * +metadatareader_retrieve(PyObject *unused, PyObject *args) +{ + PyObject *dict = NULL; + PyObject *properties = NULL; + const char *metadata_path = NULL; + + if (!PyArg_ParseTuple(args, "sO:retrieve", &metadata_path, &properties)) + return NULL; + + if ((properties != Py_None) && (PyList_Size(properties) > 0)) { + dict = read_from_properties_list(metadata_path, properties); + } else { + dict = read_all_properties(metadata_path); + } + + return dict; +} + +static PyMethodDef metadatareader_functions[] = { + {"retrieve", metadatareader_retrieve, METH_VARARGS, + PyDoc_STR("Read a dictionary from a directory with a single file " \ + "(containing the content) per key")}, + {NULL, NULL, 0, NULL} +}; + +PyMODINIT_FUNC +initmetadatareader(void) +{ + PyObject* mod; + mod = Py_InitModule("metadatareader", metadatareader_functions); + + PyObject *dbus_module = PyImport_ImportModule("dbus"); + byte_array_type = PyObject_GetAttrString(dbus_module, "ByteArray"); +} + |