Fix ptoken failed error

When get last page of gallery, the page preview count is not preview count pre page. So old version spider info file may store wrong preview count pre page. Spider info file version is added in the first line.

app/src/main/java/com/hippo/ehviewer/spider/SpiderInfo.java

@@ -24,6 +24,7 @@ import android.util.SparseArray;
 
 import com.hippo.unifile.UniFile;
 import com.hippo.yorozuya.IOUtils;
+import com.hippo.yorozuya.NumberUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -34,6 +35,9 @@ public class SpiderInfo {
 
     private static final String TAG = SpiderInfo.class.getSimpleName();
 
+    private static final String VERSION_STR = "VERSION";
+    private static final int VERSION = 2;
+
     static final String TOKEN_FAILED = "failed";
 
     int startPage = 0;
@@ -44,7 +48,6 @@ public class SpiderInfo {
     int previewPerPage = -1;
     SparseArray<String> pTokenMap = null;
 
-
     public static SpiderInfo read(@Nullable UniFile file) {
         if (file == null) {
             return null;
@@ -80,6 +83,17 @@ public class SpiderInfo {
         return startPage >= 0 ? startPage : 0;
     }
 
+    private static int getVersion(String str) {
+        if (null == str) {
+            return -1;
+        }
+        if (str.startsWith(VERSION_STR)) {
+            return NumberUtils.parseIntSafely(str.substring(VERSION_STR.length()), -1);
+        } else {
+            return 1;
+        }
+    }
+
     @SuppressWarnings("InfiniteLoopStatement")
     public static SpiderInfo read(@Nullable InputStream is) {
         if (null == is) {
@@ -89,8 +103,20 @@ public class SpiderInfo {
         SpiderInfo spiderInfo = null;
         try {
             spiderInfo = new SpiderInfo();
+            // Get version
+            String line = IOUtils.readAsciiLine(is);
+            int version = getVersion(line);
+            if (version == VERSION) {
+                // Read next line
+                line = IOUtils.readAsciiLine(is);
+            } else if (version == 1) {
+                // pass
+            } else {
+                // Invalid version
+                return null;
+            }
             // Start page
-            spiderInfo.startPage = getStartPage(IOUtils.readAsciiLine(is));
+            spiderInfo.startPage = getStartPage(line);
             // Gid
             spiderInfo.gid = Long.parseLong(IOUtils.readAsciiLine(is));
             // Token
@@ -100,7 +126,12 @@ public class SpiderInfo {
             // Preview pages
             spiderInfo.previewPages = Integer.parseInt(IOUtils.readAsciiLine(is));
             // Preview pre page
-            spiderInfo.previewPerPage = Integer.parseInt(IOUtils.readAsciiLine(is));
+            line = IOUtils.readAsciiLine(is);
+            if (version == 1) {
+                // Skip it
+            } else {
+                spiderInfo.previewPerPage = Integer.parseInt(line);
+            }
             // Pages
             spiderInfo.pages = Integer.parseInt(IOUtils.readAsciiLine(is));
             // Check pages
@@ -110,7 +141,7 @@ public class SpiderInfo {
             // PToken
             spiderInfo.pTokenMap = new SparseArray<>(spiderInfo.pages);
             while (true) { // EOFException will raise
-                String line = IOUtils.readAsciiLine(is);
+                line = IOUtils.readAsciiLine(is);
                 int pos = line.indexOf(" ");
                 if (pos > 0 || pos < line.length() - 1) {
                     int index = Integer.parseInt(line.substring(0, pos));
@@ -127,7 +158,6 @@ public class SpiderInfo {
         }
 
         if (spiderInfo == null || spiderInfo.gid == -1 || spiderInfo.token == null ||
-                spiderInfo.previewPages == -1 || spiderInfo.previewPerPage == -1 ||
                 spiderInfo.pages == -1 || spiderInfo.pTokenMap == null) {
             return null;
         } else {
@@ -139,6 +169,9 @@ public class SpiderInfo {
         OutputStreamWriter writer = null;
         try {
             writer = new OutputStreamWriter(os);
+            writer.write(VERSION_STR);
+            writer.write(Integer.toString(VERSION));
+            writer.write("\n");
             writer.write(String.format("%08x", startPage >= 0 ? startPage : 0)); // Avoid negative
             writer.write("\n");
             writer.write(Long.toString(gid));