Revert part of 59732a83c8 to fix bug#52969

While we don't need to put docstrings of .elc files into etc/DOC,
we still need to put those of `loaddefs.el` there since we don't have
a "dynamic docstring" feature for the non-compiled files and keeping
the actual docstrings in the heap would be prohibitive.

* src/Makefile.in ($(etc)/DOC): Scan `lisp/loaddefs.el` still.

* lib-src/make-docfile.c (scan_lisp_file): New function.
(scan_file): Use it.
(skip_white, read_lisp_symbol, search_lisp_doc_at_eol): New functions.

1 files changed, 359 insertions, 3 deletions

diff --git a/lib-src/make-docfile.c b/lib-src/make-docfile.c
index 33ed5ec0c92..199f1dbbcc7 100644
--- a/lib-src/make-docfile.c
+++ b/lib-src/make-docfile.c
@@ -19,8 +19,8 @@ You should have received a copy of the GNU General Public License
 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 
-/* The arguments given to this program are all the C files
- of GNU Emacs.  .c files are allowed.
+/* The arguments given to this program are all the C and some Lisp source files
+ of GNU Emacs.  .el and .c files are allowed.
  A .o file can also be specified; the .c file it was made from is used.
  This helps the makefile pass the correct list of files.
  Option -d DIR means change to DIR before looking for files.
@@ -65,6 +65,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #endif /* not DOS_NT */
 
 static void scan_file (char *filename);
+static void scan_lisp_file (const char *filename, const char *mode);
 static void scan_c_file (char *filename, const char *mode);
 static void scan_c_stream (FILE *infile);
 static void start_globals (void);
@@ -234,9 +235,14 @@ put_filename (char *filename)
 static void
 scan_file (char *filename)
 {
+  ptrdiff_t len = strlen (filename);
+
   if (!generate_globals)
     put_filename (filename);
-  scan_c_file (filename, "r");
+  if (len > 3 && !strcmp (filename + len - 3, ".el"))
+    scan_lisp_file (filename, "r");
+  else
+    scan_c_file (filename, "r");
 }
 
 static void
@@ -1214,4 +1220,354 @@ scan_c_stream (FILE *infile)
     fatal ("read error");
 }
 
+/* Read a file of Lisp source code.
+ Looks for
+  (defun NAME ARGS DOCSTRING ...)
+  (defmacro NAME ARGS DOCSTRING ...)
+  (defsubst NAME ARGS DOCSTRING ...)
+  (autoload (quote NAME) FILE DOCSTRING ...)
+  (defvar NAME VALUE DOCSTRING)
+  (defconst NAME VALUE DOCSTRING)
+  (fset (quote NAME) (make-byte-code ... DOCSTRING ...))
+  (fset (quote NAME) #[... DOCSTRING ...])
+  (defalias (quote NAME) #[... DOCSTRING ...])
+  (custom-declare-variable (quote NAME) VALUE DOCSTRING ...)
+ starting in column zero.
+ (quote NAME) may appear as 'NAME as well.
+
+ We also look for #@LENGTH CONTENTS^_ at the beginning of the line.
+ When we find that, we save it for the following defining-form,
+ and we use that instead of reading a doc string within that defining-form.
+
+ For defvar, defconst, and fset we skip to the docstring with a kludgy
+ formatting convention: all docstrings must appear on the same line as the
+ initial open-paren (the one in column zero) and must contain a backslash
+ and a newline immediately after the initial double-quote.  No newlines
+ must appear between the beginning of the form and the first double-quote.
+ For defun, defmacro, and autoload, we know how to skip over the
+ arglist, but the doc string must still have a backslash and newline
+ immediately after the double quote.
+ The only source files that follow this convention are autoload-generated
+ files like loaddefs.el;
+ The NAME and DOCSTRING are output.
+ NAME is preceded by `F' for a function or `V' for a variable.
+ An entry is output only if DOCSTRING has \ newline just after the opening ".
+ */
+
+static void
+skip_white (FILE *infile)
+{
+  int c;
+  do
+    c = getc (infile);
+  while (c_isspace (c));
+
+  ungetc (c, infile);
+}
+
+static void
+read_lisp_symbol (FILE *infile, char *buffer)
+{
+  int c;
+  char *fillp = buffer;
+
+  skip_white (infile);
+  while (true)
+    {
+      c = getc (infile);
+      if (c == '\\')
+        {
+          c = getc (infile);
+          if (c < 0)
+            return;
+          *fillp++ = c;
+        }
+      else if (c_isspace (c) || c == '(' || c == ')' || c < 0)
+        {
+          ungetc (c, infile);
+          *fillp = 0;
+          break;
+        }
+      else
+        *fillp++ = c;
+    }
+
+  if (! buffer[0])
+    fprintf (stderr, "## expected a symbol, got '%c'\n", c);
+
+  skip_white (infile);
+}
+
+static bool
+search_lisp_doc_at_eol (FILE *infile)
+{
+  int c = 0, c1 = 0, c2 = 0;
+
+  /* Skip until the end of line; remember two previous chars.  */
+  while (c != '\n' && c != '\r' && c != EOF)
+    {
+      c2 = c1;
+      c1 = c;
+      c = getc (infile);
+    }
+
+  /* If two previous characters were " and \,
+     this is a doc string.  Otherwise, there is none.  */
+  if (c2 != '"' || c1 != '\\')
+    {
+#ifdef DEBUG
+      fprintf (stderr, "## non-docstring found\n");
+#endif
+      ungetc (c, infile);
+      return false;
+    }
+  return true;
+}
+
+static void
+scan_lisp_file (const char *filename, const char *mode)
+{
+  FILE *infile;
+  int c;
+  int i;
+  int flen = strlen (filename);
+
+  if (generate_globals)
+    fatal ("scanning lisp file when -g specified");
+
+  infile = fopen (filename, mode);
+  if (infile == NULL)
+    {
+      perror (filename);
+      exit (EXIT_FAILURE);
+    }
+
+  c = '\n';
+  while (!feof (infile))
+    {
+      char buffer[BUFSIZ];
+      char type;
+
+      /* If not at end of line, skip till we get to one.  */
+      if (c != '\n' && c != '\r')
+        {
+          c = getc (infile);
+          continue;
+        }
+      /* Skip the line break.  */
+      while (c == '\n' || c == '\r')
+        c = getc (infile);
+
+      if (c != '(')
+        continue;
+
+      read_lisp_symbol (infile, buffer);
+
+      if (! strcmp (buffer, "defun")
+          || ! strcmp (buffer, "defmacro")
+          || ! strcmp (buffer, "defsubst"))
+        {
+          type = 'F';
+          read_lisp_symbol (infile, buffer);
+
+          /* Skip the arguments: either "nil" or a list in parens.  */
+
+          c = getc (infile);
+          if (c == 'n') /* nil */
+            {
+              if ((c = getc (infile)) != 'i'
+                  || (c = getc (infile)) != 'l')
+                {
+                  fprintf (stderr, "## unparsable arglist in %s (%s)\n",
+                           buffer, filename);
+                  continue;
+                }
+            }
+          else if (c != '(')
+            {
+              fprintf (stderr, "## unparsable arglist in %s (%s)\n",
+                       buffer, filename);
+              continue;
+            }
+          else
+            while (! (c == ')' || c < 0))
+              c = getc (infile);
+          skip_white (infile);
+
+          /* If the next three characters aren't `dquote bslash newline'
+             then we're not reading a docstring.
+           */
+          if ((c = getc (infile)) != '"'
+              || (c = getc (infile)) != '\\'
+              || ((c = getc (infile)) != '\n' && c != '\r'))
+            {
+#ifdef DEBUG
+              fprintf (stderr, "## non-docstring in %s (%s)\n",
+                       buffer, filename);
+#endif
+              continue;
+            }
+        }
+
+      else if (! strcmp (buffer, "defvar")
+               || ! strcmp (buffer, "defconst")
+               || ! strcmp (buffer, "defcustom"))
+        {
+          type = 'V';
+          read_lisp_symbol (infile, buffer);
+
+          if (!search_lisp_doc_at_eol (infile))
+            continue;
+        }
+
+      else if (! strcmp (buffer, "custom-declare-variable")
+               || ! strcmp (buffer, "defvaralias")
+               )
+        {
+          type = 'V';
+
+          c = getc (infile);
+          if (c == '\'')
+            read_lisp_symbol (infile, buffer);
+          else
+            {
+              if (c != '(')
+                {
+                  fprintf (stderr,
+                           "## unparsable name in custom-declare-variable in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              if (strcmp (buffer, "quote"))
+                {
+                  fprintf (stderr,
+                           "## unparsable name in custom-declare-variable in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              c = getc (infile);
+              if (c != ')')
+                {
+                  fprintf (stderr,
+                           "## unparsable quoted name in custom-declare-variable in %s\n",
+                           filename);
+                  continue;
+                }
+            }
+
+          if (!search_lisp_doc_at_eol (infile))
+            continue;
+        }
+
+      else if (! strcmp (buffer, "fset") || ! strcmp (buffer, "defalias"))
+        {
+          type = 'F';
+
+          c = getc (infile);
+          if (c == '\'')
+            read_lisp_symbol (infile, buffer);
+          else
+            {
+              if (c != '(')
+                {
+                  fprintf (stderr, "## unparsable name in fset in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              if (strcmp (buffer, "quote"))
+                {
+                  fprintf (stderr, "## unparsable name in fset in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              c = getc (infile);
+              if (c != ')')
+                {
+                  fprintf (stderr,
+                           "## unparsable quoted name in fset in %s\n",
+                           filename);
+                  continue;
+                }
+            }
+
+          if (!search_lisp_doc_at_eol (infile))
+            continue;
+        }
+
+      else if (! strcmp (buffer, "autoload"))
+        {
+          type = 'F';
+          c = getc (infile);
+          if (c == '\'')
+            read_lisp_symbol (infile, buffer);
+          else
+            {
+              if (c != '(')
+                {
+                  fprintf (stderr, "## unparsable name in autoload in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              if (strcmp (buffer, "quote"))
+                {
+                  fprintf (stderr, "## unparsable name in autoload in %s\n",
+                           filename);
+                  continue;
+                }
+              read_lisp_symbol (infile, buffer);
+              c = getc (infile);
+              if (c != ')')
+                {
+                  fprintf (stderr,
+                           "## unparsable quoted name in autoload in %s\n",
+                           filename);
+                  continue;
+                }
+            }
+          skip_white (infile);
+          c = getc (infile);
+          if (c != '\"')
+            {
+              fprintf (stderr, "## autoload of %s unparsable (%s)\n",
+                       buffer, filename);
+              continue;
+            }
+          read_c_string_or_comment (infile, 0, false, 0);
+
+          if (!search_lisp_doc_at_eol (infile))
+            continue;
+        }
+
+#ifdef DEBUG
+      else if (! strcmp (buffer, "if")
+               || ! strcmp (buffer, "byte-code"))
+        continue;
+#endif
+
+      else
+        {
+#ifdef DEBUG
+          fprintf (stderr, "## unrecognized top-level form, %s (%s)\n",
+                   buffer, filename);
+#endif
+          continue;
+        }
+
+      /* At this point, we should gobble a doc string from the input file.
+         The opening quote (and leading backslash-newline)
+         have already been read.  */
+
+      printf ("\037%c%s\n", type, buffer);
+      read_c_string_or_comment (infile, 1, false, 0);
+    }
+  if (ferror (infile) || fclose (infile) != 0)
+    fatal ("%s: read error", filename);
+}
+
+
 /* make-docfile.c ends here */