From: Trent Huber <trentmhuber@gmail.com>
Date: Thu, 4 Sep 2025 19:18:46 +0000 (-0400)
Subject: Fix history when running multiple sessions
X-Git-Url: https://trenthuber.com/code?a=commitdiff_plain;h=3c1d0429d62a82b76a037989ce9bf12fe21cdad7;p=thus.git

Fix history when running multiple sessions
---

diff --git a/src/history.c b/src/history.c
index 899eaf9..2c50ba5 100644
--- a/src/history.c
+++ b/src/history.c
@@ -16,9 +16,18 @@
 
 static struct {
 	char path[PATH_MAX], entries[MAXHIST + 1][MAXCHARS + 1];
-	size_t b, c, t;
+	size_t b, s, c, t;
 } history;
 
+static void readhistory(FILE *file) {
+	history.b = history.t = 0;
+	while (fgets(history.entries[history.t], sizeof*history.entries, file)) {
+		history.entries[history.t][strlen(history.entries[history.t]) - 1] = '\0';
+		if (INC(t) == history.b) INC(b);
+	}
+	history.s = history.c = history.t;
+}
+
 void inithistory(void) {
 	FILE *file;
 
@@ -29,12 +38,8 @@ void inithistory(void) {
 		if (errno == ENOENT) return;
 		fatal("Unable to open history file for reading");
 	}
-	while (fgets(history.entries[history.t], sizeof*history.entries, file)) {
-		history.entries[history.t][strlen(history.entries[history.t]) - 1] = '\0';
-		if ((history.c = INC(t)) == history.b) INC(b);
-	}
-	if (ferror(file) || !feof(file))
-		fatal("Unable to read from history file");
+	readhistory(file);
+	if (ferror(file) || !feof(file)) fatal("Unable to read from history file");
 	if (fclose(file) == EOF) fatal("Unable to close history file");
 }
 
@@ -52,33 +57,50 @@ int gethistory(int back, char *buffer) {
 
 void sethistory(char *buffer) {
 	strcpy(history.entries[history.t], buffer);
-	if ((history.c = INC(t)) == history.b) INC(b);
+	history.c = INC(t);
+	if (history.t == history.b) INC(b);
+	if (history.t == history.s) INC(s);
 	*history.entries[history.t] = '\0';
 }
 
+static void writehistory(FILE *file) {
+	for (history.c = history.b; history.c != history.t; INC(c)) {
+		if (fputs(history.entries[history.c], file) == EOF) {
+			note("Unable to write to history file");
+			break;
+		}
+		if (fputc('\n', file) == EOF) {
+			note("Unable to terminate line of history file");
+			break;
+		}
+	}
+}
+
 void deinithistory(void) {
 	int fd;
 	FILE *file;
 
 	if (!interactive) return;
 
-	if ((fd = open(history.path, O_WRONLY | O_CREAT | O_TRUNC, 0600)) == -1) {
+	if ((fd = open(history.path, O_WRONLY | O_CREAT | O_APPEND, 0600)) == -1) {
 		note("Unable to open history file for writing");
 		return;
 	}
-	if (!(file = fdopen(fd, "w"))) {
+	if (!(file = fdopen(fd, "a"))) {
 		note("Unable to open history file descriptor as FILE pointer");
 		return;
 	}
-	for (history.c = history.b; history.c != history.t; INC(c)) {
-		if (fputs(history.entries[history.c], file) == EOF) {
-			note("Unable to write to history file");
-			break;
-		}
-		if (fputc('\n', file) == EOF) {
-			note("Unable to terminate line of history file");
-			break;
-		}
+	history.b = history.s;
+	writehistory(file);
+	if (!freopen(history.path, "r", file)) {
+		note("Unable to reopen history file for reading");
+		return;
+	}
+	readhistory(file);
+	if (!freopen(history.path, "w", file)) {
+		note("Unable to reopen history file for writing");
+		return;
 	}
+	writehistory(file);
 	if (fclose(file) == EOF) note("Unable to close history stream");
 }