Added history through the --history=<name> flag.

2 files changed, 129 insertions, 14 deletions

diff --git a/README.md b/README.md
index 1d8a036..ece7021 100644
--- a/README.md
+++ b/README.md
@@ -17,5 +17,20 @@ Here's a simple program to move a file from the current directory:
     file="`ls | ask "Pick a file: "`"
     mv "$file" "`ask "Move $file to: "`"
 
+`ask` also supports a few other command line options:
+
+* `ask -y` or `ask --yes` and `ask -n` or `ask --no` will append " [Y/n]" or
+  " [y/N]" respectively to the prompt, and provide "Y" and "N" as the only
+  options, and will exit with success or failure accordingly. (e.g. `if ask
+  --yes "Continue?"; then ...`)
+* `ask --quickpick` or `ask -Q` will pick an option automatically without
+  pressing enter if there is only one valid option.
+* `ask --password` or `ask -P` will show a typing indicator without displaying
+  the typed letters on the screen. (e.g. `password="$(ask -P "Enter your
+  password: ")"`)
+* `ask --history=<name>` will load/save previous `ask` responses in
+  `$XDG_DATA/ask/<name>.hist` (`~/.local/share/ask/<name>.hist` by default) for
+  use with up/down arrow keys. Maximum of 1000 entries are stored per log file.
+
 ## License
 `ask` is released under the MIT License. See LICENSE for details.
diff --git a/ask.c b/ask.c
index 62f4052..c0fefed 100644
--- a/ask.c
+++ b/ask.c
@@ -1,20 +1,26 @@
 /* ask - a simple command line asker
  * Copyright 2019 Bruce Hill
  * Released under the MIT License (see LICENSE for details)
- * Usage: ask [-Q|--quickpick] [-y|--yes] [-n|--no] [-p|--password]
- *   [-v|--version] [-h|--help] [-q |--query=initial] [[--prompt=]prompt [options...]]
+ * Usage: ask [-Q|--quickpick] [-y|--yes] [-n|--no] [-P|--password] [[-H |--history=]name]
+ *   [-v|--version] [-h|--help] [-q |--query=initial] [[-p |--prompt=]prompt [options...]]
  *    --password: password mode
  *    --quickpick: quickpick mode (exit when only one option remains)
  *    --version: print version and exit
  *    --help: print usage and exit
  *    --query: initial value to pre-populate user input
  *    --prompt: use the given prompt (displayed in bold)
- *    --yes: append "[Y/n]" to the prompt, use quickpick mode, 
+ *    --yes: append " [Y/n]" to the prompt, use quickpick mode, 
+ *    --no: append " [y/N]" to the prompt, use quickpick mode, 
+ *    --history: store the selected value in a history file, which can be browsed with
+ *        up/down arrow keys
  */
+#include <errno.h>
+#include <limits.h>
 #include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <termios.h>
@@ -26,8 +32,10 @@
 #define LOWERCASE(c) ('A' <= (c) && (c) <= 'Z' ? ((c) + 'a' - 'A') : (c))
 #define EQ(a, b) (case_sensitive ? (a) == (b) : LOWERCASE(a) == LOWERCASE(b))
 #define PASSWORD "-\\|/"
+#define MAX_HISTORY 1000
 
-static int password = 0, quickpick = 0, case_sensitive = 0;
+static int password = 0, quickpick = 0, case_sensitive = 0, histindex = 0, nhistory = 0;
+static char histpath[PATH_MAX] = {0};
 
 static inline void *memcheck(void *p)
 {
@@ -139,6 +147,29 @@ static int draw_line(FILE *out, const char *option, const char *patt, int cursor
     return to_start;
 }
 
+static void get_history(char **buf, size_t *cap, int index)
+{
+    if (nhistory == 0) return;
+    if (index == nhistory) {
+        (*buf)[0] = '\0';
+        return;
+    }
+    FILE *f = fopen(histpath, "r");
+    char histline[256];
+    for (int i = 0; i < histindex; i++) {
+        if (fgets(histline, sizeof(histline), f) == NULL)
+            return;
+        if (histline[strlen(histline)-1] != '\n')
+            --i;
+    }
+    do {
+        *buf = memcheck(realloc(*buf, (*cap += 100)));
+        if (fgets(*buf, *cap, f) == NULL)
+            return;
+    } while ((*buf)[strlen(*buf)-1] != '\n');
+    (*buf)[strlen(*buf)-1] = '\0';
+}
+
 /*
  * A basic fuzzy matcher and line inputter
  */
@@ -264,6 +295,24 @@ static char *get_input(FILE *in, FILE *out, const char *prompt, const char *init
             case KEY_ARROW_RIGHT: case KEY_CTRL_F:
                 if (b < len) ++b;
                 break;
+            case KEY_ARROW_UP:
+                if (nhistory > 0) {
+                    --histindex;
+                    if (histindex < 0) histindex = 0;
+                    get_history(&buf, &cap, histindex);
+                    len = strlen(buf);
+                    b = len;
+                }
+                break;
+            case KEY_ARROW_DOWN:
+                if (nhistory > 0) {
+                    ++histindex;
+                    if (histindex > nhistory) histindex = nhistory;
+                    get_history(&buf, &cap, histindex);
+                    len = strlen(buf);
+                    b = len;
+                }
+                break;
             case KEY_CTRL_Q: case KEY_CTRL_V: {
                 int nextkey;
                 while ((nextkey = bgetkey(in, NULL, NULL, -1)) < 0)
@@ -318,7 +367,7 @@ static int cmp_len(const void *v1, const void *v2)
 int main(int argc, char *argv[])
 {
     int yes = 0, no = 0;
-    char *prompt = NULL, *query = NULL;
+    char *prompt = NULL, *query = NULL, *histname = NULL;
     char **opts = NULL;
     size_t linescap = 0, linecap = 0;
     int nopts = 0;
@@ -334,9 +383,12 @@ int main(int argc, char *argv[])
             opts[nopts++] = memcheck(strdup(line));
         }
     }
-    int a = 1;
-    while (a < argc) {
-        if (argv[a][0] == '-' && argv[a][1] != '-') {
+    int a;
+    for (a = 1; a < argc; a++) {
+        if (strcmp(argv[a], "-H") == 0) {
+            histname = argv[++a];
+            continue;
+        } else if (argv[a][0] == '-' && argv[a][1] != '-') {
             for (char *p = &argv[a][1]; *p; p++) {
                 switch (*p) {
                     case 'P': password = 1; break;
@@ -357,6 +409,8 @@ int main(int argc, char *argv[])
             query = &argv[a][strlen("--query=")];
         } else if (strcmp(argv[a], "--password") == 0) {
             password = 1;
+        } else if (strncmp(argv[a], "--history=", strlen("--history=")) == 0) {
+            histname = &argv[a][strlen("--history=")];
         } else if (strcmp(argv[a], "--quickpick") == 0) {
             quickpick = 1;
         } else if (strcmp(argv[a], "--yes") == 0) {
@@ -376,7 +430,6 @@ int main(int argc, char *argv[])
             printf("ask %s\n", ASK_VERSION);
             return 0;
         } else break;
-        ++a;
     }
     if (!prompt && a < argc) prompt = argv[a++];
 
@@ -396,12 +449,12 @@ int main(int argc, char *argv[])
     if (yes) {
         char *p2 = memcheck(calloc((prompt ? strlen(prompt) : 0)+5+1, sizeof(char)));
         if (prompt) strcpy(p2, prompt);
-        strcat(p2, "[Y/n]");
+        strcat(p2, " [Y/n]");
         prompt = p2;
     } else if (no) {
         char *p2 = memcheck(calloc((prompt ? strlen(prompt) : 0)+5+1, sizeof(char)));
         if (prompt) strcpy(p2, prompt);
-        strcat(p2, "[y/N]");
+        strcat(p2, " [y/N]");
         prompt = p2;
     }
 
@@ -415,6 +468,41 @@ int main(int argc, char *argv[])
     if (tcsetattr(fileno(tty_out), TCSAFLUSH, &bb_termios) == -1)
         return 1;
 
+    if (histname) {
+        char *xdg_data = getenv("XDG_DATA_HOME");
+        if (xdg_data == NULL) {
+            strcpy(histpath, getenv("HOME"));
+            strcat(histpath, "/.local/.share/ask/");
+        } else {
+            strcpy(histpath, xdg_data);
+            strcat(histpath, "/ask/");
+        }
+        strcat(histpath, histname);
+
+        for (char* p = strchr(histpath + 1, '/'); p; p = strchr(p + 1, '/')) {
+            *p = '\0';
+            if (mkdir(histpath, 0777) == -1) {
+                if (errno != EEXIST) {
+                    *p = '/';
+                    printf("Error: could not create history directory at %s", histpath);
+                    return 1;
+                }
+            }
+            *p = '/';
+        }
+
+        char buf[1024];
+        FILE *f = fopen(histpath, "r");
+        if (f) {
+            while (fgets(buf, sizeof(buf), f) != NULL) {
+                size_t len = strlen(buf);
+                if (len > 1 && buf[len-1] == '\n')
+                    ++nhistory;
+            }
+            histindex = nhistory;
+        }
+    }
+
     // Prefer shorter matches, but otherwise use alphabetic order
     qsort(opts, (size_t)nopts, sizeof(char*), cmp_len);
     char *output = get_input(tty_in, tty_out, prompt, query, nopts, opts);
@@ -430,12 +518,24 @@ int main(int argc, char *argv[])
     // the program is exiting
     if (!output) return 1;
 
-    fputs(output, stdout);
     if (yes)
-        return strcmp(output, "n") == 0 && strcmp(output, "N") == 0;
+        return strcmp(output, "N") == 0;
     if (no)
-        return strcmp(output, "y") != 0 && strcmp(output, "Y") != 0;
+        return strcmp(output, "Y") != 0;
+
+    fputs(output, stdout);
 
+    if (histpath[0] && strlen(output) > 0) {
+        FILE *f = fopen(histpath, "a");
+        fprintf(f, "%s\n", output);
+        fclose(f);
+        if (++nhistory > MAX_HISTORY) {
+            if (fork() == 0) {
+                char *args[] = {"sed", "-i", "1d", histpath, NULL};
+                execvp("sed", args);
+            }
+        }
+    }
     return 0;
 }
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1