srd: don't check directory structure a PD is in, but what it implements.

Also added extra check to require start() and decode() methods in the
PD's Decoder class.

1 files changed, 41 insertions, 103 deletions

diff --git a/decoder.c b/decoder.c
index 65d05d0..7dd1e96 100644
--- a/decoder.c
+++ b/decoder.c
@@ -18,10 +18,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <glib.h>
 #include "config.h"
 #include "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
 #include "sigrokdecode-internal.h"
+#include <dirent.h>
 
 /* The list of protocol decoders. */
 GSList *pd_list = NULL;
@@ -75,12 +75,12 @@ struct srd_decoder *srd_get_decoder_by_id(const char *id)
  */
 int srd_load_decoder(const char *name, struct srd_decoder **dec)
 {
-	PyObject *py_basedec, *py_annlist, *py_ann;
+	PyObject *py_basedec, *py_method, *py_annlist, *py_ann;
 	struct srd_decoder *d;
 	int alen, ret, i;
 	char **ann;
 
-	py_basedec = NULL;
+	py_basedec = py_method = NULL;
 
 	srd_dbg("decoder: %s: loading module '%s'", __func__, name);
 
@@ -106,7 +106,7 @@ int srd_load_decoder(const char *name, struct srd_decoder **dec)
 		/* This generated an AttributeError exception. */
 		PyErr_Print();
 		PyErr_Clear();
-		srd_err("Decoder class not found in protocol decoder module %s", name);
+		srd_err("Decoder class not found in protocol decoder %s", name);
 		goto err_out;
 	}
 
@@ -122,6 +122,34 @@ int srd_load_decoder(const char *name, struct srd_decoder **dec)
 	}
 	Py_DecRef(py_basedec);
 
+	/* Check for a proper start() method. */
+	if (!PyObject_HasAttrString(d->py_dec, "start")) {
+		srd_err("Protocol decoder %s has no start() method Decoder "
+				"class.", name);
+		goto err_out;
+	}
+	py_method = PyObject_GetAttrString(d->py_dec, "start");
+	if (!PyFunction_Check(py_method)) {
+		srd_err("Protocol decoder %s Decoder class attribute 'start'"
+				"is not a method.", name);
+		goto err_out;
+	}
+	Py_DecRef(py_method);
+
+	/* Check for a proper decode() method. */
+	if (!PyObject_HasAttrString(d->py_dec, "decode")) {
+		srd_err("Protocol decoder %s has no decode() method Decoder "
+				"class.", name);
+		goto err_out;
+	}
+	py_method = PyObject_GetAttrString(d->py_dec, "decode");
+	if (!PyFunction_Check(py_method)) {
+		srd_err("Protocol decoder %s Decoder class attribute 'decode' "
+				"is not a method.", name);
+		goto err_out;
+	}
+	Py_DecRef(py_method);
+
 	if (py_attr_as_str(d->py_dec, "id", &(d->id)) != SRD_OK)
 		goto err_out;
 
@@ -170,6 +198,7 @@ int srd_load_decoder(const char *name, struct srd_decoder **dec)
 
 err_out:
 	if (ret != SRD_OK) {
+		Py_XDECREF(py_method);
 		Py_XDECREF(py_basedec);
 		Py_XDECREF(d->py_dec);
 		Py_XDECREF(d->py_mod);
@@ -231,117 +260,26 @@ int srd_unload_decoder(struct srd_decoder *dec)
 	return SRD_OK;
 }
 
-/**
- * Check if the directory in the specified search path is a valid PD dir.
- *
- * A valid sigrok protocol decoder consists of a directory, which contains
- * at least two .py files (the special __init__.py and at least one additional
- * .py file which contains the actual PD code).
- *
- * TODO: We should also check that this is not a random other Python module,
- * but really a sigrok PD module by some means.
- *
- * @param search_path A string containing the (absolute) path to the directory
- *                    where 'entry' resides in.
- * @param entry A string containing the (relative) directory name of the
- *              sigrok PD module. E.g. "i2c" for the I2C protocol decoder.
- * @return SRD_OK, if the directory is a valid sigrok PD, a negative error
- *         code, such as SRD_ERR, otherwise.
- */
-int srd_is_valid_pd_dir(const gchar *search_path, const gchar *entry)
-{
-	GDir *dir;
-	int py_files = 0, has_init_py = 0;
-	gchar *path1, *path2, *file;
-	GError *error;
-
-	/* TODO: Error handling. */
-	path1 = g_build_filename(search_path, entry, NULL);
-
-	/* Check that it is a directory (and exists). */
-	if (!g_file_test(path1, G_FILE_TEST_IS_DIR)) {
-		srd_dbg("decoder: %s: '%s' not a directory or doesn't exist",
-			__func__, entry);
-		return SRD_ERR;
-	}
-
-	if (!(dir = g_dir_open(path1, 0, &error))) { /* TODO: flags? */
-		srd_dbg("decoder: %s: '%s' failed to open directory",
-			__func__, entry);
-		return SRD_ERR;
-	}
-
-	/* Check the contents of the directory. */
-	while ((file = g_dir_read_name(dir)) != NULL) {
-		/* TODO: Error handling. */
-		path2 = g_build_filename(path1, file, NULL);
-
-		/* Ignore non-files. */
-		if (!g_file_test(path2, G_FILE_TEST_IS_REGULAR)) {
-			srd_spew("decoder: %s: '%s' not a file, ignoring",
-				 __func__, file);
-			continue;
-		}
-
-		/* Count number of .py files. */
-		if (g_str_has_suffix(path2, ".py")) {
-			srd_spew("decoder: %s: found .py file: '%s'",
-				 __func__, file);
-			py_files++;
-		}
-
-		/* Check if it's an __init__.py file. */
-		if (g_str_has_suffix(path2, "__init__.py")) {
-			srd_spew("decoder: %s: found __init__.py file: '%s'",
-				 __func__, path2);
-			has_init_py = 1;
-		}
-	}
-	g_dir_close(dir);
-
-	/* Check if the directory contains >= 2 *.py files. */
-	if (py_files < 2) {
-		srd_dbg("decoder: %s: '%s' is not a valid PD dir, it doesn't "
-			"contain >= 2 .py files", __func__, entry);
-		return SRD_ERR;
-	}
-
-	/* Check if the directory contains an __init__.py file. */
-	if (!has_init_py) {
-		srd_dbg("decoder: %s: '%s' is not a valid PD dir, it doesn't "
-			"contain an __init__.py file", __func__, entry);
-		return SRD_ERR;
-	}
-
-	/* TODO: Check if it's a PD, not a random other Python module. */
-
-	return SRD_OK;
-}
-
 int srd_load_all_decoders(void)
 {
-	GDir *dir;
-	gchar *direntry;
+	DIR *dir;
+	struct dirent *dp;
 	int ret;
 	char *decodername;
 	struct srd_decoder *dec;
-	GError *error;
 
-	if (!(dir = g_dir_open(DECODERS_DIR, 0, &error))) { /* TODO: flags? */
+	if (!(dir = opendir(DECODERS_DIR))) {
 		Py_Finalize(); /* Returns void. */
 		return SRD_ERR_DECODERS_DIR;
 	}
 
-	while ((direntry = g_dir_read_name(dir)) != NULL) {
-		/* Ignore directory entries which are not valid PDs. */
-		if (srd_is_valid_pd_dir(DECODERS_DIR, direntry) != SRD_OK) {
-			srd_dbg("decoder: %s: '%s' not a valid PD dir, "
-				"ignoring it", __func__, direntry);
+	while ((dp = readdir(dir)) != NULL) {
+		/* Ignore filenames which don't end with ".py". */
+		if (!g_str_has_suffix(dp->d_name, ".py"))
 			continue;
-		}
 
 		/* The decoder name is the PD directory name (e.g. "i2c"). */
-		decodername = g_strdup(direntry);
+		decodername = g_strndup(dp->d_name, strlen(dp->d_name) - 3);
 
 		/* TODO: Error handling. Use g_try_malloc(). */
 		if (!(dec = malloc(sizeof(struct srd_decoder)))) {
@@ -356,7 +294,7 @@ int srd_load_all_decoders(void)
 			pd_list = g_slist_append(pd_list, dec);
 		}
 	}
-	g_dir_close(dir);
+	closedir(dir);
 
 	return SRD_OK;
 }