Extract tempfile module from fileio

Though this module is relatively small it has very clear boundaries.
The last argument for extracting `tempfile` was the errors which I got
when I was writing unittests for it: `cimport './src/nvim/fileio.h'`
does not work for some reason.

src/nvim/diff.c

@@ -30,6 +30,7 @@
 #include "nvim/path.h"
 #include "nvim/screen.h"
 #include "nvim/strings.h"
+#include "nvim/tempfile.h"
 #include "nvim/undo.h"
 #include "nvim/window.h"
 #include "nvim/os/os.h"

src/nvim/eval.c

@@ -68,6 +68,7 @@
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/tag.h"
+#include "nvim/tempfile.h"
 #include "nvim/term.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"

src/nvim/ex_cmds.c

@@ -59,6 +59,7 @@
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/tag.h"
+#include "nvim/tempfile.h"
 #include "nvim/term.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"

src/nvim/fileio.c

@@ -49,6 +49,7 @@
 #include "nvim/search.h"
 #include "nvim/sha256.h"
 #include "nvim/strings.h"
+#include "nvim/tempfile.h"
 #include "nvim/term.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
@@ -5156,115 +5157,6 @@ void write_lnum_adjust(linenr_T offset)
     curbuf->b_no_eol_lnum += offset;
 }
 
-/* Name of Vim's own temp dir. Ends in a slash. */
-static char_u *vim_tempdir = NULL;
-static uint32_t temp_count = 0;             /* Temp filename counter. */
-
-/*
- * This will create a directory for private use by this instance of Vim.
- * This is done once, and the same directory is used for all temp files.
- * This method avoids security problems because of symlink attacks et al.
- * It's also a bit faster, because we only need to check for an existing
- * file when creating the directory and not for each temp file.
- */
-static void vim_maketempdir(void)
-{
-  static const char *temp_dirs[] = TEMP_DIR_NAMES;
-  int i;
-  /*
-   * Try the entries in `TEMP_DIR_NAMES` to create the temp directory.
-   */
-  char_u itmp[TEMP_FILE_PATH_MAXLEN];
-  for (i = 0; i < (int)(sizeof(temp_dirs) / sizeof(char *)); ++i) {
-    /* expand $TMP, leave room for "/nvimXXXXXX/999999999" */
-    expand_env((char_u *)temp_dirs[i], itmp, TEMP_FILE_PATH_MAXLEN - 22);
-    if (os_isdir(itmp)) {                    /* directory exists */
-      add_pathsep(itmp);
-
-      /* Leave room for filename */
-      STRCAT(itmp, "nvimXXXXXX");
-      if (os_mkdtemp((char *)itmp) != NULL)
-        vim_settempdir(itmp);
-      if (vim_tempdir != NULL)
-        break;
-    }
-  }
-}
-
-/*
- * Delete the temp directory and all files it contains.
- */
-void vim_deltempdir(void)
-{
-  char_u      **files;
-  int file_count;
-  int i;
-
-  if (vim_tempdir != NULL) {
-    sprintf((char *)NameBuff, "%s*", vim_tempdir);
-    if (gen_expand_wildcards(1, &NameBuff, &file_count, &files,
-            EW_DIR|EW_FILE|EW_SILENT) == OK) {
-      for (i = 0; i < file_count; ++i)
-        os_remove((char *)files[i]);
-      FreeWild(file_count, files);
-    }
-    path_tail(NameBuff)[-1] = NUL;
-    os_rmdir((char *)NameBuff);
-
-    free(vim_tempdir);
-    vim_tempdir = NULL;
-  }
-}
-
-char_u *vim_gettempdir(void)
-{
-  if (vim_tempdir == NULL) {
-    vim_maketempdir();
-  }
-
-  return vim_tempdir;
-}
-
-/*
- * Directory "tempdir" was created.  Expand this name to a full path and put
- * it in "vim_tempdir".  This avoids that using ":cd" would confuse us.
- * "tempdir" must be no longer than MAXPATHL.
- */
-static void vim_settempdir(char_u *tempdir)
-{
-  char_u *buf = verbose_try_malloc((size_t)MAXPATHL + 2);
-  if (buf) {
-    if (vim_FullName(tempdir, buf, MAXPATHL, FALSE) == FAIL)
-      STRCPY(buf, tempdir);
-    add_pathsep(buf);
-    vim_tempdir = vim_strsave(buf);
-    free(buf);
-  }
-}
-
-/*
- * vim_tempname(): Return a unique name that can be used for a temp file.
- *
- * The temp file is NOT created.
- *
- * The returned pointer is to allocated memory.
- * The returned pointer is NULL if no valid name was found.
- */
-char_u *vim_tempname(void)
-{
-  char_u itmp[TEMP_FILE_PATH_MAXLEN];
-
-  char_u *tempdir = vim_gettempdir();
-  if (tempdir != NULL) {
-    /* There is no need to check if the file exists, because we own the
-     * directory and nobody else creates a file in it. */
-    sprintf((char *)itmp, "%s%" PRIu32, tempdir, temp_count++);
-    return vim_strsave(itmp);
-  }
-
-  return NULL;
-}
-
 #if defined(BACKSLASH_IN_FILENAME) || defined(PROTO)
 /*
  * Convert all backslashes in fname to forward slashes in-place.

src/nvim/hardcopy.c

@@ -40,6 +40,7 @@
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/term.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/os/os.h"
 

src/nvim/if_cscope.c

@@ -28,6 +28,7 @@
 #include "nvim/quickfix.h"
 #include "nvim/strings.h"
 #include "nvim/tag.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/window.h"
 #include "nvim/os/os.h"

src/nvim/memline.c

@@ -69,6 +69,7 @@
 #include "nvim/spell.h"
 #include "nvim/strings.h"
 #include "nvim/term.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
 #include "nvim/window.h"

src/nvim/misc1.c

@@ -52,6 +52,7 @@
 #include "nvim/strings.h"
 #include "nvim/tag.h"
 #include "nvim/term.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
 #include "nvim/window.h"

src/nvim/os/server.c

@@ -11,7 +11,7 @@
 #include "nvim/vim.h"
 #include "nvim/memory.h"
 #include "nvim/message.h"
-#include "nvim/fileio.h"
+#include "nvim/tempfile.h"
 #include "nvim/map.h"
 
 #define MAX_CONNECTIONS 32

src/nvim/os_unix.c

@@ -52,6 +52,7 @@
 #include "nvim/screen.h"
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
+#include "nvim/tempfile.h"
 #include "nvim/term.h"
 #include "nvim/ui.h"
 #include "nvim/os/os.h"

src/nvim/quickfix.c

@@ -47,6 +47,7 @@
 #include "nvim/search.h"
 #include "nvim/strings.h"
 #include "nvim/term.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/window.h"
 #include "nvim/os/os.h"

src/nvim/spell.c

@@ -322,6 +322,7 @@
 #include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/term.h"
+#include "nvim/tempfile.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
 #include "nvim/os/os.h"

src/nvim/tempfile.c

@@ -0,0 +1,124 @@
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "nvim/ascii.h"
+#include "nvim/memory.h"
+#include "nvim/misc1.h"
+#include "nvim/os/os.h"
+#include "nvim/path.h"
+#include "nvim/strings.h"
+#include "nvim/tempfile.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "tempfile.c.generated.h"
+#endif
+
+/* Name of Vim's own temp dir. Ends in a slash. */
+static char_u *vim_tempdir = NULL;
+static uint32_t temp_count = 0;             /* Temp filename counter. */
+
+/*
+ * This will create a directory for private use by this instance of Vim.
+ * This is done once, and the same directory is used for all temp files.
+ * This method avoids security problems because of symlink attacks et al.
+ * It's also a bit faster, because we only need to check for an existing
+ * file when creating the directory and not for each temp file.
+ */
+static void vim_maketempdir(void)
+{
+  static const char *temp_dirs[] = TEMP_DIR_NAMES;
+  int i;
+  /*
+   * Try the entries in `TEMP_DIR_NAMES` to create the temp directory.
+   */
+  char_u itmp[TEMP_FILE_PATH_MAXLEN];
+  for (i = 0; i < (int)(sizeof(temp_dirs) / sizeof(char *)); ++i) {
+    /* expand $TMP, leave room for "/nvimXXXXXX/999999999" */
+    expand_env((char_u *)temp_dirs[i], itmp, TEMP_FILE_PATH_MAXLEN - 22);
+    if (os_isdir(itmp)) {                    /* directory exists */
+      add_pathsep(itmp);
+
+      /* Leave room for filename */
+      STRCAT(itmp, "nvimXXXXXX");
+      if (os_mkdtemp((char *)itmp) != NULL)
+        vim_settempdir(itmp);
+      if (vim_tempdir != NULL)
+        break;
+    }
+  }
+}
+
+/*
+ * Delete the temp directory and all files it contains.
+ */
+void vim_deltempdir(void)
+{
+  char_u      **files;
+  int file_count;
+  int i;
+
+  if (vim_tempdir != NULL) {
+    sprintf((char *)NameBuff, "%s*", vim_tempdir);
+    if (gen_expand_wildcards(1, &NameBuff, &file_count, &files,
+            EW_DIR|EW_FILE|EW_SILENT) == OK) {
+      for (i = 0; i < file_count; ++i)
+        os_remove((char *)files[i]);
+      FreeWild(file_count, files);
+    }
+    path_tail(NameBuff)[-1] = NUL;
+    os_rmdir((char *)NameBuff);
+
+    free(vim_tempdir);
+    vim_tempdir = NULL;
+  }
+}
+
+char_u *vim_gettempdir(void)
+{
+  if (vim_tempdir == NULL) {
+    vim_maketempdir();
+  }
+
+  return vim_tempdir;
+}
+
+/*
+ * Directory "tempdir" was created.  Expand this name to a full path and put
+ * it in "vim_tempdir".  This avoids that using ":cd" would confuse us.
+ * "tempdir" must be no longer than MAXPATHL.
+ */
+static void vim_settempdir(char_u *tempdir)
+{
+  char_u *buf = verbose_try_malloc((size_t)MAXPATHL + 2);
+  if (buf) {
+    if (vim_FullName(tempdir, buf, MAXPATHL, FALSE) == FAIL)
+      STRCPY(buf, tempdir);
+    add_pathsep(buf);
+    vim_tempdir = vim_strsave(buf);
+    free(buf);
+  }
+}
+
+/*
+ * vim_tempname(): Return a unique name that can be used for a temp file.
+ *
+ * The temp file is NOT created.
+ *
+ * The returned pointer is to allocated memory.
+ * The returned pointer is NULL if no valid name was found.
+ */
+char_u *vim_tempname(void)
+{
+  char_u itmp[TEMP_FILE_PATH_MAXLEN];
+
+  char_u *tempdir = vim_gettempdir();
+  if (tempdir != NULL) {
+    /* There is no need to check if the file exists, because we own the
+     * directory and nobody else creates a file in it. */
+    sprintf((char *)itmp, "%s%" PRIu32, tempdir, temp_count++);
+    return vim_strsave(itmp);
+  }
+
+  return NULL;
+}

src/nvim/tempfile.h

@@ -0,0 +1,8 @@
+#ifndef NVIM_TEMPFILE_H
+#define NVIM_TEMPFILE_H
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "tempfile.h.generated.h"
+#endif
+
+#endif  // NVIM_TEMPFILE_H