packfs.py: only compile packed_fs.c when files in data/ have changed

Author: dingo35

SmartEVSE-3/packfs.py

@@ -5,33 +5,47 @@
 if not os.path.isfile("data/update2.html"):
     print("Missing file: data/update2.html")
     sys.exit(1)
+
 if os.path.isdir("pack.tmp"):
     shutil.rmtree('pack.tmp')
 try:
-    filelist = []
-    os.makedirs('pack.tmp/data')
-    # now gzip the stuff except zones.csv since this file is not served by mongoose but directly accessed:
-    for file in os.listdir("data"):
-        filename = os.fsdecode(file)
-        if filename == "cert.pem" or filename == "key.pem" or filename == "CH32V203.bin" or filename == "SmartEVSE.webp":
-            shutil.copy('data/' + filename, 'pack.tmp/data/' + filename)
-            filelist.append('data/' + filename)
-            continue
-        else:
-            with open('data/' + filename, 'rb') as f_in, gzip.open('pack.tmp/data/' + filename + '.gz', 'wb') as f_out:
-                f_out.writelines(f_in)
-            filelist.append('data/' + filename + '.gz')
-            continue
-    os.chdir('pack.tmp')
-    cmdstring = 'python ../pack.py ' + ' '.join(filelist)
-    os.system(cmdstring + '>../src/packed_fs.c')
-    os.chdir('..')
+    # Skip generation if packed_fs.c is newer than everything in data/
+    OUTPUT = "src/packed_fs.c"
+    if os.path.isfile(OUTPUT):
+        packed_mtime = os.path.getmtime(OUTPUT)
+        latest = 0
+        for root, _, files in os.walk("data"):
+            for f in files:
+                try:
+                    mtime = os.path.getmtime(os.path.join(root, f))
+                    if mtime > latest: latest = mtime
+                except: pass
+        if latest > packed_mtime:
+            filelist = []
+            os.makedirs('pack.tmp/data')
+            # now gzip the stuff except zones.csv since this file is not served by mongoose but directly accessed:
+            for file in os.listdir("data"):
+                filename = os.fsdecode(file)
+                if filename == "cert.pem" or filename == "key.pem" or filename == "CH32V203.bin" or filename == "SmartEVSE.webp":
+                    shutil.copy('data/' + filename, 'pack.tmp/data/' + filename)
+                    filelist.append('data/' + filename)
+                    continue
+                else:
+                    with open('data/' + filename, 'rb') as f_in, gzip.open('pack.tmp/data/' + filename + '.gz', 'wb') as f_out:
+                        f_out.writelines(f_in)
+                    filelist.append('data/' + filename + '.gz')
+                    continue
+            os.chdir('pack.tmp')
+            cmdstring = 'python ../pack.py ' + ' '.join(filelist)
+            os.system(cmdstring + '>../src/packed_fs.c')
+            os.chdir('..')
 except Exception as e:
     print(f"An error occurred: {str(e)}")
     sys.exit(100)
-if shutil.rmtree("pack.tmp"):
-    print("Failed to clean up temporary files")
-    sys.exit(9)
+if os.path.isdir("pack.tmp"):
+    if shutil.rmtree("pack.tmp"):
+        print("Failed to clean up temporary files")
+        sys.exit(9)
 # cleanup CH32 bin file if it was generated:
 if os.path.isfile("data/CH32V203.bin"):
     os.remove("data/CH32V203.bin")