extract: add extract_finish_wide(), and optionally skip stripping trailing empty cells

extract_finish() returns the extracted text in UTF-8, while
extract_finish_wide() returns the extracted text in Unicode.

This patch also adds a new argument to extract_finish{,_wide},
that when set to true, skips stripping trailing empty cells.

extract.c

@@ -51,10 +51,9 @@ ensure_size(struct extraction_context *ctx, size_t additional_chars)
 }
 
 bool
-extract_finish(struct extraction_context *ctx, char **text, size_t *len)
+extract_finish_wide(struct extraction_context *ctx, bool strip_trailing_empty,
+                    wchar_t **text, size_t *len)
 {
-    bool ret = false;
-
     if (text == NULL)
         return false;
 
@@ -63,12 +62,24 @@ extract_finish(struct extraction_context *ctx, char **text, size_t *len)
         *len = 0;
 
     if (ctx->failed)
-        goto out;
+        goto err;
+
+    if (!strip_trailing_empty) {
+        /* Insert pending newlines, and replace empty cells with spaces */
+        if (!ensure_size(ctx, ctx->newline_count + ctx->empty_count))
+            goto err;
+
+        for (size_t i = 0; i < ctx->newline_count; i++)
+            ctx->buf[ctx->idx++] = L'\n';
+
+        for (size_t i = 0; i < ctx->empty_count; i++)
+            ctx->buf[ctx->idx++] = L' ';
+    }
 
     if (ctx->idx == 0) {
         /* Selection of empty cells only */
         if (!ensure_size(ctx, 1))
-            goto out;
+            goto err;
         ctx->buf[ctx->idx++] = L'\0';
     } else {
         xassert(ctx->idx > 0);
@@ -77,12 +88,39 @@ extract_finish(struct extraction_context *ctx, char **text, size_t *len)
             ctx->buf[ctx->idx - 1] = L'\0';
         else {
             if (!ensure_size(ctx, 1))
-                goto out;
+                goto err;
             ctx->buf[ctx->idx++] = L'\0';
         }
     }
 
-    size_t _len = wcstombs(NULL, ctx->buf, 0);
+    *text = ctx->buf;
+    if (len != NULL)
+        *len = ctx->idx - 1;
+    free(ctx);
+    return true;
+
+err:
+    free(ctx->buf);
+    free(ctx);
+    return false;
+}
+
+bool
+extract_finish(struct extraction_context *ctx, bool strip_trailing_empty,
+               char **text, size_t *len)
+{
+    if (text == NULL)
+        return false;
+    if (len != NULL)
+        *len = 0;
+
+    wchar_t *wtext;
+    if (!extract_finish_wide(ctx, strip_trailing_empty, &wtext, NULL))
+        return false;
+
+    bool ret = false;
+
+    size_t _len = wcstombs(NULL, wtext, 0);
     if (_len == (size_t)-1) {
         LOG_ERRNO("failed to convert selection to UTF-8");
         goto out;
@@ -94,7 +132,7 @@ extract_finish(struct extraction_context *ctx, char **text, size_t *len)
         goto out;
     }
 
-    wcstombs(*text, ctx->buf, _len + 1);
+    wcstombs(*text, wtext, _len + 1);
 
     if (len != NULL)
         *len = _len;
@@ -102,8 +140,7 @@ extract_finish(struct extraction_context *ctx, char **text, size_t *len)
     ret = true;
 
 out:
-    free(ctx->buf);
+    free(wtext);
-    free(ctx);
     return ret;
 }
 

extract.h

@@ -2,6 +2,7 @@
 
 #include <stddef.h>
 #include <stdbool.h>
+#include <wchar.h>
 
 #include "terminal.h"
 
@@ -14,4 +15,8 @@ bool extract_one(
     int col, void *context);
 
 bool extract_finish(
-    struct extraction_context *context, char **text, size_t *len);
+    struct extraction_context *context, bool strip_trailing_empty,
+    char **text, size_t *len);
+bool extract_finish_wide(
+    struct extraction_context *context, bool strip_trailing_empty,
+    wchar_t **text, size_t *len);

selection.c

@@ -224,7 +224,7 @@ selection_to_text(const struct terminal *term)
         &extract_one_const_wrapper, ctx);
 
     char *text;
-    return extract_finish(ctx, &text, NULL) ? text : NULL;
+    return extract_finish(ctx, true, &text, NULL) ? text : NULL;
 }
 
 void

terminal.c

@@ -2917,7 +2917,7 @@ rows_to_text(const struct terminal *term, int start, int end,
     }
 
 out:
-    return extract_finish(ctx, text, len);
+    return extract_finish(ctx, true, text, len);
 }
 
 bool