[RFC Patch v2 1/3] notmuch-opts.[ch]: new argument parsing framework for notmuch.

[David Bremner]

From: David Bremner <bremner at debian.org>

As we noticed when Jani kindly converted things to getopt_long, much
of the work in argument parsing in notmuch is due to the the key-value
style arguments like --format=(raw|json|text).

In this version I implement Austin Clements' suggestion of basing the
main API on taking pointers to output variables.
---
 Makefile.local |    1 +
 notmuch-opts.c |  120 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 notmuch-opts.h |   50 +++++++++++++++++++++++
 3 files changed, 171 insertions(+), 0 deletions(-)
 create mode 100644 notmuch-opts.c
 create mode 100644 notmuch-opts.h

diff --git a/Makefile.local b/Makefile.local
index c94402b..6606be8 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -303,6 +303,7 @@ notmuch_client_srcs =		\
 	notmuch-count.c		\
 	notmuch-dump.c		\
 	notmuch-new.c		\
+	notmuch-opts.c		\
 	notmuch-reply.c		\
 	notmuch-restore.c	\
 	notmuch-search.c	\
diff --git a/notmuch-opts.c b/notmuch-opts.c
new file mode 100644
index 0000000..a8c5223
--- /dev/null
+++ b/notmuch-opts.c
@@ -0,0 +1,120 @@
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include "error_util.h"
+#include "notmuch-opts.h"
+
+/*
+  Search the list of keywords for a given argument, assigning the
+  output variable to the corresponding value.  Return FALSE if nothing
+  matches.
+*/
+
+static notmuch_bool_t
+_process_keyword_arg (const notmuch_opt_desc_t *arg_desc, const char *arg_str) {
+
+    if (arg_str[0] != ':' && arg_str[0] != '=') {
+	return FALSE;
+    }
+
+    /* skip delimiter */
+    arg_str++;
+
+    notmuch_keyword_t *keywords = arg_desc->keywords;
+
+    while (keywords->name) {
+	if (strcmp (arg_str, keywords->name) == 0) {
+	    if (arg_desc->output_var) {
+		*((int *)arg_desc->output_var) = keywords->value;
+	    }
+	    return TRUE;
+	}
+	keywords++;
+    }
+    return FALSE;
+}
+
+/*
+   Search for the {pos_arg_index}th position argument, return FALSE if
+   that does not exist.
+*/
+
+notmuch_bool_t
+parse_position_arg (const char *arg_str, int pos_arg_index, const notmuch_opt_desc_t *arg_desc) {
+
+    int pos_arg_counter = 0;
+    while (arg_desc->name){
+	if (arg_desc->opt_type == NOTMUCH_OPT_POSITION) {
+	    if (pos_arg_counter == pos_arg_index) {
+		if (arg_desc->output_var) {
+		    *((const char **)arg_desc->output_var) = arg_str;
+		}
+		return TRUE;
+	    }
+	    pos_arg_counter++;
+	}
+	arg_desc++;
+    }
+    return FALSE;
+}
+
+notmuch_opt_result_t
+parse_option (const char *arg,
+	      const notmuch_opt_desc_t *options){
+
+    assert(arg);
+    assert(options);
+
+    arg += 2;
+
+    const notmuch_opt_desc_t *try = options;
+    while (try->name) {
+	if (strncmp (arg, try->name, strlen(try->name)) == 0) {
+
+	    switch (try->opt_type) {
+	    case NOTMUCH_OPT_KEYWORD:
+		return  _process_keyword_arg (try, arg+strlen(try->name));
+		break;
+	    case NOTMUCH_OPT_BOOLEAN:
+		return TRUE;
+		break;
+	    case NOTMUCH_OPT_POSITION:
+	    case NOTMUCH_OPT_NULL:
+	    default:
+		INTERNAL_ERROR ("unknown or unhandled option type %d", try->opt_type);
+		/*UNREACHED*/
+	    }
+	}
+	try++;
+    }
+    return FALSE;
+}
+
+int
+notmuch_parse_args (int argc, char **argv, const notmuch_opt_desc_t *options, int opt_index){
+
+    int pos_arg_index = 0;
+    notmuch_bool_t more_args = TRUE;
+
+    while (more_args && opt_index < argc) {
+	if (strncmp (argv[opt_index],"--",2) != 0) {
+
+	    more_args = parse_position_arg (argv[opt_index], pos_arg_index, options);
+
+	    if (more_args) {
+		pos_arg_index++;
+		opt_index++;
+	    }
+
+	} else {
+
+	    if (strlen (argv[opt_index]) == 2)
+		return opt_index+1;
+
+	    more_args = parse_option (argv[opt_index], options);
+	    opt_index++;
+	}
+    }
+
+    return opt_index;
+}
diff --git a/notmuch-opts.h b/notmuch-opts.h
new file mode 100644
index 0000000..75d65cb
--- /dev/null
+++ b/notmuch-opts.h
@@ -0,0 +1,50 @@
+#ifndef NOTMUCH_OPTS_H
+#define NOTMUCH_OPTS_H
+
+#include "notmuch.h"
+
+enum notmuch_opt_type {
+    NOTMUCH_OPT_NULL = 0,
+    NOTMUCH_OPT_BOOLEAN,
+    NOTMUCH_OPT_KEYWORD,
+    NOTMUCH_OPT_POSITION
+};
+
+typedef enum notmuch_opt_result {
+    NOTMUCH_OPT_ERROR = -2,
+    NOTMUCH_OPT_GOT_POS = -1,
+    NOTMUCH_OPT_STOP = 0,
+    NOTMUCH_OPT_SUCCESS = 1
+} notmuch_opt_result_t;
+
+typedef struct notmuch_keyword {
+    const char *name;
+    int value;
+} notmuch_keyword_t;
+
+typedef struct notmuch_opt_desc {
+    const char *name;
+    int  arg_id;
+    enum notmuch_opt_type opt_type;
+    struct notmuch_keyword *keywords;
+    void *output_var;
+} notmuch_opt_desc_t;
+
+typedef struct notmuch_opt {
+    int arg_id;
+    int keyword_id;
+    const char *string;
+} notmuch_opt_t;
+
+notmuch_bool_t
+parse_option (const char *arg, const notmuch_opt_desc_t* options);
+
+notmuch_bool_t
+parse_position_arg (const char *arg,
+		    int position_arg_index,
+		    const notmuch_opt_desc_t* options);
+
+int
+notmuch_parse_args(int argc, char **argv, const notmuch_opt_desc_t *options, int opt_index);
+
+#endif
-- 
1.7.5.4