Reduces count of open and close calls on fd

jmattaa · Nov 12, 2024 · 0c6f56f · 0c6f56f
1 parent 99f6c4e
commit 0c6f56f
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Showing 3 changed files with 74 additions and 16 deletions.
diff --git a/include/filetypes/checktypes.h b/include/filetypes/checktypes.h
@@ -11,7 +11,8 @@ struct laser_magicnumber
 
 int laser_checktype(const char *filename,
                     const struct laser_magicnumber formats[]);
-
+int laser_checktype_ex(int fd, const char *filename,
+                       const struct laser_magicnumber formats[]);
 extern const struct laser_magicnumber laser_archiveformats[];
 extern const struct laser_magicnumber laser_mediaformats[];
 extern const struct laser_magicnumber laser_documentformats[];

diff --git a/src/filetypes/checktype.c b/src/filetypes/checktype.c
@@ -5,26 +5,27 @@
 #include <string.h>
 #include <unistd.h>
 
-int laser_checktype(const char *filename,
-                    const struct laser_magicnumber formats[])
+enum check_type_return
+{
+    Success = 0,
+    NotOpened,
+    CannotRead,
+    Unknown
+};
+static int laser_checktype_fd(int fd, const struct laser_magicnumber formats[])
 {
-    int fd = open(filename, O_RDONLY);
     if (fd == -1)
     {
-        perror("open");
-        return 0;
+        return NotOpened;
     }
-
     // should be updated if there is a magic number larger than 8 bits
     unsigned char buffer[8];
 
     ssize_t bytesRead = read(fd, buffer, sizeof(buffer));
-    close(fd);
 
     if (bytesRead < 0)
     {
-        fprintf(stderr, "laser: cannot read %s", filename);
-        return 0;
+        return CannotRead;
     }
 
     size_t i = 0;
@@ -33,9 +34,62 @@ int laser_checktype(const char *filename,
     {
         if (bytesRead >= formats[i].magic_size &&
             memcmp(buffer, formats[i].magic, formats[i].magic_size) == 0)
-            return 1;
+            return Success;
         i++;
     }
 
-    return 0;
+    return Unknown;
+}
+
+int laser_checktype(const char *filename,
+                    const struct laser_magicnumber formats[])
+{
+    int fd = open(filename, O_RDONLY);
+    if (fd == -1)
+    {
+        perror("open");
+        return 0;
+    }
+    int rv = laser_checktype_fd(fd, formats);
+    // should be updated if there is a magic number larger than 8 bits
+    switch (rv)
+    {
+        case NotOpened:
+            perror("open");
+            break;
+        case CannotRead:
+            fprintf(stderr, "laser: cannot read %s", filename);
+            break;
+            //Fallthrough
+        default:
+            break;
+    }
+    close(fd);
+    return rv == Success;
+}
+
+int laser_checktype_ex(int fd, const char *filename,
+                       const struct laser_magicnumber formats[])
+{
+
+    if (fd == -1)
+    {
+        perror("open");
+        return 0;
+    }
+    int rv = laser_checktype_fd(fd, formats);
+    // should be updated if there is a magic number larger than 8 bits
+    switch (rv)
+    {
+        case NotOpened:
+            perror("open");
+            break;
+        case CannotRead:
+            fprintf(stderr, "laser: cannot read %s", filename);
+            break;
+            //Fallthrough
+        default:
+            break;
+    }
+    return rv == Success;
 }
diff --git a/src/laser.c b/src/laser.c
@@ -3,7 +3,7 @@
 #include "filetypes/checktypes.h"
 #include "git/lgit.h"
 #include "utils.h"
-
+#include <fcntl.h>
 #define BRANCH_SIZE 8
 
 char *strip_parent_dir(const char *full_path, const char *parent_dir)
@@ -142,6 +142,8 @@ void laser_process_entries(laser_opts opts, int depth, int max_depth,
         }
         else
         {
+            int fd = open(full_path, O_RDONLY);
+
             if (S_ISLNK(file_stat.st_mode) && opts.show_symlinks)
             {
                 char symlink_target[PATH_MAX];
@@ -163,17 +165,17 @@ void laser_process_entries(laser_opts opts, int depth, int max_depth,
                                   LASER_COLORS[LASER_COLOR_EXEC].value, indent,
                                   depth, is_last);
 
-            else if (laser_checktype(full_path, laser_archiveformats))
+            else if (laser_checktype_ex(fd, full_path, laser_archiveformats))
                 laser_print_entry(entries[i]->d_name,
                                   LASER_COLORS[LASER_COLOR_ARCHIVE].value,
                                   indent, depth, is_last);
 
-            else if (laser_checktype(full_path, laser_mediaformats))
+            else if (laser_checktype_ex(fd, full_path, laser_mediaformats))
                 laser_print_entry(entries[i]->d_name,
                                   LASER_COLORS[LASER_COLOR_MEDIA].value, indent,
                                   depth, is_last);
 
-            else if (laser_checktype(full_path, laser_documentformats))
+            else if (laser_checktype_ex(fd, full_path, laser_documentformats))
                 laser_print_entry(entries[i]->d_name,
                                   LASER_COLORS[LASER_COLOR_DOCUMENT].value,
                                   indent, depth, is_last);
@@ -187,6 +189,7 @@ void laser_process_entries(laser_opts opts, int depth, int max_depth,
                 laser_print_entry(entries[i]->d_name,
                                   LASER_COLORS[LASER_COLOR_FILE].value, indent,
                                   depth, is_last);
+            close(fd);
         }
 
         free(entries[i]);