py/repl: Refactor autocomplete, extracting reusable parts.

Originally at adafruit#4548

Signed-off-by: Artyom Skrobov <[email protected]>

Author: tyomitch

py/repl.c

@@ -143,6 +143,87 @@ bool mp_repl_continue_with_input(const char *input) {
     return false;
 }
 
+STATIC bool test_qstr(mp_obj_t obj, qstr name) {
+    // try object member
+    mp_obj_t dest[2];
+    mp_load_method_protected(obj, name, dest, true);
+    return dest[0] != MP_OBJ_NULL;
+}
+
+STATIC const char *find_completions(const char *s_start, size_t s_len,
+    mp_obj_t obj, size_t *match_len, qstr *q_first, qstr *q_last) {
+
+    const char *match_str = NULL;
+    *match_len = 0;
+    *q_first = *q_last = 0;
+    size_t nqstr = QSTR_TOTAL();
+    for (qstr q = MP_QSTR_ + 1; q < nqstr; ++q) {
+        size_t d_len;
+        const char *d_str = (const char *)qstr_data(q, &d_len);
+        // special case; filter out words that begin with underscore
+        // unless there's already a partial match
+        if (s_len == 0 && d_str[0] == '_') {
+            continue;
+        }
+        if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
+            if (test_qstr(obj, q)) {
+                if (match_str == NULL) {
+                    match_str = d_str;
+                    *match_len = d_len;
+                } else {
+                    // search for longest common prefix of match_str and d_str
+                    // (assumes these strings are null-terminated)
+                    for (size_t j = s_len; j <= *match_len && j <= d_len; ++j) {
+                        if (match_str[j] != d_str[j]) {
+                            *match_len = j;
+                            break;
+                        }
+                    }
+                }
+                if (*q_first == 0) {
+                    *q_first = q;
+                }
+                *q_last = q;
+            }
+        }
+    }
+    return match_str;
+}
+
+STATIC void print_completions(const mp_print_t *print,
+    const char *s_start, size_t s_len,
+    mp_obj_t obj, qstr q_first, qstr q_last) {
+
+    #define WORD_SLOT_LEN (16)
+    #define MAX_LINE_LEN  (4 * WORD_SLOT_LEN)
+
+    int line_len = MAX_LINE_LEN; // force a newline for first word
+    for (qstr q = q_first; q <= q_last; ++q) {
+        size_t d_len;
+        const char *d_str = (const char *)qstr_data(q, &d_len);
+        if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
+            if (test_qstr(obj, q)) {
+                int gap = (line_len + WORD_SLOT_LEN - 1) / WORD_SLOT_LEN * WORD_SLOT_LEN - line_len;
+                if (gap < 2) {
+                    gap += WORD_SLOT_LEN;
+                }
+                if (line_len + gap + d_len <= MAX_LINE_LEN) {
+                    // TODO optimise printing of gap?
+                    for (int j = 0; j < gap; ++j) {
+                        mp_print_str(print, " ");
+                    }
+                    mp_print_str(print, d_str);
+                    line_len += gap + d_len;
+                } else {
+                    mp_printf(print, "\n%s", d_str);
+                    line_len = d_len;
+                }
+            }
+        }
+    }
+    mp_print_str(print, "\n");
+}
+
 size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print, const char **compl_str) {
     // scan backwards to find start of "a.b.c" chain
     const char *org_str = str;
@@ -155,8 +236,6 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
         }
     }
 
-    size_t nqstr = QSTR_TOTAL();
-
     // begin search in outer global dict which is accessed from __main__
     mp_obj_t obj = MP_OBJ_FROM_PTR(&mp_module___main__);
     mp_obj_t dest[2];
@@ -196,40 +275,10 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
     }
 
     // look for matches
-    const char *match_str = NULL;
-    size_t match_len = 0;
-    qstr q_first = 0, q_last = 0;
-    for (qstr q = MP_QSTR_ + 1; q < nqstr; ++q) {
-        size_t d_len;
-        const char *d_str = (const char *)qstr_data(q, &d_len);
-        // special case; filter out words that begin with underscore
-        // unless there's already a partial match
-        if (s_len == 0 && d_str[0] == '_') {
-            continue;
-        }
-        if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
-            mp_load_method_protected(obj, q, dest, true);
-            if (dest[0] != MP_OBJ_NULL) {
-                if (match_str == NULL) {
-                    match_str = d_str;
-                    match_len = d_len;
-                } else {
-                    // search for longest common prefix of match_str and d_str
-                    // (assumes these strings are null-terminated)
-                    for (size_t j = s_len; j <= match_len && j <= d_len; ++j) {
-                        if (match_str[j] != d_str[j]) {
-                            match_len = j;
-                            break;
-                        }
-                    }
-                }
-                if (q_first == 0) {
-                    q_first = q;
-                }
-                q_last = q;
-            }
-        }
-    }
+    size_t match_len;
+    qstr q_first, q_last;
+    const char *match_str =
+        find_completions(s_start, s_len, obj, &match_len, &q_first, &q_last);
 
     // nothing found
     if (q_first == 0) {
@@ -257,36 +306,7 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
     }
 
     // multiple matches found, print them out
-
-    #define WORD_SLOT_LEN (16)
-    #define MAX_LINE_LEN  (4 * WORD_SLOT_LEN)
-
-    int line_len = MAX_LINE_LEN; // force a newline for first word
-    for (qstr q = q_first; q <= q_last; ++q) {
-        size_t d_len;
-        const char *d_str = (const char *)qstr_data(q, &d_len);
-        if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
-            mp_load_method_protected(obj, q, dest, true);
-            if (dest[0] != MP_OBJ_NULL) {
-                int gap = (line_len + WORD_SLOT_LEN - 1) / WORD_SLOT_LEN * WORD_SLOT_LEN - line_len;
-                if (gap < 2) {
-                    gap += WORD_SLOT_LEN;
-                }
-                if (line_len + gap + d_len <= MAX_LINE_LEN) {
-                    // TODO optimise printing of gap?
-                    for (int j = 0; j < gap; ++j) {
-                        mp_print_str(print, " ");
-                    }
-                    mp_print_str(print, d_str);
-                    line_len += gap + d_len;
-                } else {
-                    mp_printf(print, "\n%s", d_str);
-                    line_len = d_len;
-                }
-            }
-        }
-    }
-    mp_print_str(print, "\n");
+    print_completions(print, s_start, s_len, obj, q_first, q_last);
 
     return (size_t)(-1); // indicate many matches
 }