From 9f580cac8584767e1167db9d9b1515826f79d1b9 Mon Sep 17 00:00:00 2001
From: Christian Neukirchen <chneukirchen@gmail.com>
Date: Mon, 11 Jul 2016 14:23:59 +0200
Subject: [PATCH] add thread

---
 thread.c | 250 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 250 insertions(+)
 create mode 100644 thread.c

diff --git a/thread.c b/thread.c
new file mode 100644
index 0000000..e1201ac
--- /dev/null
+++ b/thread.c
@@ -0,0 +1,250 @@
+/* jwz-style threading
+ * clean-room implementation of https://www.jwz.org/doc/threading.html
+ * without looking at any code
+ *
+ * subject threading and sibling sorting is not done yet
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <wchar.h>
+
+#include <search.h>
+
+
+#include "blaze822.h"
+
+struct container {
+        char *mid;
+	char *file;
+	struct message *msg;
+	struct container *parent;
+	struct container *child;
+	struct container *next;
+};
+
+static void *mids;
+
+int
+midorder(const void *a, const void *b)
+{
+        struct container *ia = (struct container *)a;
+        struct container *ib = (struct container *)b;
+
+	return strcmp(ia->mid, ib->mid);
+}
+
+char *
+mid(struct message *msg)
+{
+	char *v;
+	v = blaze822_hdr(msg, "message-id");
+	// XXX intern mid?
+	if (v) {
+		char *m;
+
+		m = strchr(v, '<');
+		if (!m)
+			return 0;
+		v = strchr(m, '>');
+		if (!v)
+			return 0;
+		return strndup(m+1, v-m-1);
+	}
+	else
+		return 0;
+}
+
+struct container *
+midcont(char *mid)
+{
+	struct container key, **result;
+	key.mid = mid;
+
+	if (!(result = tfind(&key, &mids, midorder))) {
+		struct container *c = malloc(sizeof (struct container));
+		c->mid = mid;
+		c->file = 0;
+		c->msg = 0;
+		c->parent = c->child = c->next = 0;
+		printf("ADD %s\n", mid);
+		return *(struct container **)tsearch(c, &mids, midorder);
+	} else {
+		return *result;
+	}
+}
+
+struct container *
+store_id(char *file, struct message *msg)
+{
+	struct container *c;
+
+	c = midcont(mid(msg));
+	c->file = file;
+	c->msg = msg;
+
+	return c;
+}
+
+void
+thread(char *file)
+{
+	struct message *msg;
+
+	msg = blaze822(file);
+	if (!msg)
+		return;
+
+	struct container *c = store_id(file, msg);
+
+	char *mid = "";
+
+	char *v;
+	struct container *parent = 0, *me = 0;
+
+	v = blaze822_hdr(msg, "references");
+	if (v) {
+		char *m, *n;
+		parent = 0;
+		while (1) {
+			m = strchr(v, '<');
+			if (!m)
+				break;
+			v = strchr(m, '>');
+			if (!v)
+				break;
+			mid = strndup(m+1, v-m-1);
+			// XXX free?
+
+			printf("ref |%s|\n", mid);
+
+			me = midcont(mid);
+			if (parent && !me->parent) {
+				me->parent = me;
+				parent->child = me;
+			}
+
+			parent = me;
+		}
+	}
+	
+	v = blaze822_hdr(msg, "in-reply-to");
+	char *irt;
+	if (v) {
+		char *m, *n;
+		m = strchr(v, '<');
+		if (!m)
+			goto out;
+		v = strchr(m, '>');
+		if (!v)
+			goto out;
+		irt = strndup(m+1, v-m-1);
+		printf("irt |%s|\n", irt);
+		
+		if (strcmp(irt, mid) != 0) {
+			parent = midcont(irt);
+		}
+	}
+out:
+
+	if (parent) {
+		c->parent = parent;
+		parent->child = c;
+	}
+}
+
+struct container *top;
+struct container *lastc;
+
+void
+find_root(const void *nodep, const VISIT which, const int depth)
+{
+        (void)depth;
+
+        if (which == postorder || which == leaf) {
+		struct container *c = *(struct container **)nodep;
+
+		if (!c->parent) {
+//			printf("%s\n", c->mid);
+			printf("root %s\n", c->mid);
+			lastc->next = c;
+			c->next = 0;
+			lastc = c;
+		}
+	}
+}
+
+void
+find_roots()
+{
+	top = malloc (sizeof (struct container));
+	top->msg = 0;
+	top->next = top->child = top->parent = 0;
+	top->mid = "(top)";
+
+	lastc = top;
+
+	twalk(mids, find_root);
+}
+
+void
+print_tree(struct container *c, int depth)
+{
+	do {
+		if (depth >= 0) {
+			int i;
+			for (i = 0; i < depth; i++)
+				printf(" ");
+			if (c->file)
+				printf("%s\n", c->file);
+			else
+				printf("<%s>\n", c->mid);
+		}
+	
+		if (c->child)
+			print_tree(c->child, depth+1);
+	} while (c = c->next);
+}
+
+int
+main(int argc, char *argv[])
+{
+	char *s;
+	
+	char *line = 0;
+	size_t linelen = 0;
+	int read;
+
+	int i = 0;
+
+	if (argc == 1 || (argc == 2 && strcmp(argv[1], "-") == 0)) {
+		while ((read = getdelim(&line, &linelen, '\n', stdin)) != -1) {
+			if (line[read-1] == '\n') line[read-1] = 0;
+			printf("%s\n", line);
+			thread(line);
+			i++;
+		}
+	} else {
+		for (i = 1; i < argc; i++) {
+			thread(argv[i]);
+		}
+		i--;
+	}
+
+	printf("%d mails scanned\n", i);
+	
+	find_roots();
+
+	print_tree(top, -1);
+
+	return 0;
+}