3 files changed, 23 insertions, 20 deletions

diff --git a/archive.h b/archive.h
index 6cc7c5f..5a80748 100644
--- a/archive.h
+++ b/archive.h
@@ -59,7 +59,6 @@ static inline void envelopeFree(struct Envelope envelope) {
 }
 
 #define TEMPLATE(...) #__VA_ARGS__
-#define ESCAPE_URL_CAP(len) (3 * (len))
 
 struct Variable {
 	const char *name;
@@ -73,8 +72,9 @@ int escapeXML(FILE *file, const char *str);
 
 int templateRender(
 	FILE *file, const char *template,
-	const struct Variable *vars, EscapeFn *escape
+	const struct Variable vars[], EscapeFn *escape
 );
+char *templateURL(const char *template, const struct Variable vars[]);
 
 #define MBOX_HEADERS \
 	"Date Subject From Sender Reply-To To Cc Bcc " \
diff --git a/html.c b/html.c
index 85b6f6b..e404434 100644
--- a/html.c
+++ b/html.c
@@ -14,7 +14,6 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#include <assert.h>
 #include <err.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -50,21 +49,7 @@ int htmlEnvelope(FILE *file, const struct Envelope *envelope) {
 		{ "messageID", envelope->messageID },
 		{0},
 	};
-
-	size_t cap = sizeof(Mailto);
-	for (struct Variable *var = mailtoVars; var->value; ++var) {
-		cap += ESCAPE_URL_CAP(strlen(var->value));
-	}
-	char *mailto = malloc(cap);
-	if (!mailto) err(EX_OSERR, "malloc");
-
-	FILE *url = fmemopen(mailto, cap, "w");
-	if (!url) err(EX_OSERR, "fmemopen");
-
-	int error = 0
-		|| templateRender(url, Mailto, mailtoVars, escapeURL)
-		|| fclose(url);
-	assert(!error);
+	char *mailto = templateURL(Mailto, mailtoVars);
 
 	const char *from = envelope->from.name;
 	if (!from) from = envelope->from.mailbox;
@@ -84,7 +69,7 @@ int htmlEnvelope(FILE *file, const struct Envelope *envelope) {
 		{ "date", date },
 		{0},
 	};
-	error = templateRender(file, Summary, summaryVars, escapeXML);
+	int error = templateRender(file, Summary, summaryVars, escapeXML);
 	free(mailto);
 	if (error) return error;
 
diff --git a/template.c b/template.c
index 92c6381..426f1d0 100644
--- a/template.c
+++ b/template.c
@@ -68,7 +68,7 @@ int escapeXML(FILE *file, const char *str) {
 
 int templateRender(
 	FILE *file, const char *template,
-	const struct Variable *vars, EscapeFn *escape
+	const struct Variable vars[], EscapeFn *escape
 ) {
 	for (bool subst = false; *template; subst ^= true) {
 		size_t len = strcspn(template, "[]");
@@ -97,3 +97,21 @@ int templateRender(
 	}
 	return 0;
 }
+
+char *templateURL(const char *template, const struct Variable vars[]) {
+	size_t cap = 3 * strlen(template) + 1;
+	for (const struct Variable *var = vars; var->name; ++var) {
+		cap += 3 * strlen(var->value);
+	}
+
+	char *buf = malloc(cap);
+	if (!buf) err(EX_OSERR, "malloc");
+
+	FILE *file = fmemopen(buf, cap, "w");
+	if (!file) err(EX_OSERR, "fmemopen");
+
+	int error = templateRender(file, template, vars, escapeURL) || fclose(file);
+	assert(!error);
+
+	return buf;
+}