Correctly try to open split files.

src/file_compound.cpp

@@ -21,6 +21,7 @@
 #include "file_compound.h"
 
 #include <errno.h>
+#include <stdexcept>
 #include <string.h>
 #include <sys/stat.h>
 #include <zim/tools.h>
@@ -40,30 +41,48 @@ void FileCompound::addPart(FilePart* fpart)
   _fsize += fpart->size();
 }
 
+std::shared_ptr<FileCompound> FileCompound::openSinglePieceOrSplitZimFile(std::string filename) {
+  std::shared_ptr<FileCompound> fileCompound;
+  if (filename.size() > 6 && filename.substr(filename.size()-6) == ".zimaa") {
+    filename.resize(filename.size()-2);
+  } else {
+  try {
+      fileCompound = std::make_shared<FileCompound>(filename);
+    } catch(...) { }
+  }
+
+  if ( !fileCompound ) {
+    fileCompound = std::make_shared<FileCompound>(filename, FileCompound::MultiPartToken::Multi);
+  }
+  return fileCompound;
+}
+
 FileCompound::FileCompound(const std::string& filename):
   _filename(filename),
   _fsize(0)
+{
+  addPart(new FilePart(filename));
+}
+
+FileCompound::FileCompound(const std::string& base_filename, MultiPartToken _token):
+  _filename(base_filename),
+  _fsize(0)
 {
   try {
-    addPart(new FilePart(filename));
-  } catch(...) {
-    int errnoSave = errno;
-    _fsize = zsize_t(0);
-    try {
-      for (char ch0 = 'a'; ch0 <= 'z'; ++ch0)
+    for (char ch0 = 'a'; ch0 <= 'z'; ++ch0)
+    {
+      const std::string fname0 = base_filename + ch0;
+      for (char ch1 = 'a'; ch1 <= 'z'; ++ch1)
       {
-        const std::string fname0 = filename + ch0;
-        for (char ch1 = 'a'; ch1 <= 'z'; ++ch1)
-        {
-          addPart(new FilePart(fname0 + ch1));
-        }
+        addPart(new FilePart(fname0 + ch1));
       }
-    } catch (...) { }
-
-    if (empty())
-      throw std::runtime_error(Formatter()
-                               << "error " << errnoSave << " opening file \""
-                               << filename << "\"");
+    }
+  } catch (std::runtime_error& e) {
+    // This catch acts as a break for the double loop.
+  }
+  if (empty()) {
+    // We haven't found any part
+    throw std::runtime_error(Formatter() << "Error opening as a split file: " << base_filename);
   }
 }
 

src/file_compound.h

@@ -25,6 +25,7 @@
 #include "zim_types.h"
 #include "debug.h"
 #include <map>
+#include <memory>
 #include <vector>
 
 namespace zim {
@@ -53,9 +54,12 @@ class FileCompound : private std::map<Range, FilePart*, less_range> {
   public: // types
     typedef const_iterator PartIterator;
     typedef std::pair<PartIterator, PartIterator> PartRange;
+    enum class MultiPartToken { Multi };
 
   public: // functions
+    static std::shared_ptr<FileCompound> openSinglePieceOrSplitZimFile(std::string filename);
     explicit FileCompound(const std::string& filename);
+    explicit FileCompound(const std::string& filename, MultiPartToken token);
 
 #ifndef _WIN32
     explicit FileCompound(int fd);

src/fileimpl.cpp

@@ -163,7 +163,7 @@ class Grouping
   // FileImpl
   //
   FileImpl::FileImpl(const std::string& fname)
-    : FileImpl(std::make_shared<FileCompound>(fname))
+    : FileImpl(FileCompound::openSinglePieceOrSplitZimFile(fname))
   {}
 
 #ifndef _WIN32
@@ -207,6 +207,15 @@ class Grouping
       throw ZimFileFormatError("error reading zim-file header.");
     }
 
+    // This can happen for several reasons:
+    // - Zim file is corrupted (corrupted header)
+    // - Zim file is too small (ongoing download, truncated file...)
+    // - Zim file is embedded at beginning of another file (and we try to open the file as a zim file)
+    //   If open through a FdInput, size should be set in FdInput.
+    if (header.hasChecksum() && (header.getChecksumPos() + 16) != size_type(zimReader->size())) {
+      throw ZimFileFormatError("Zim file(s) is of bad size or corrupted.");
+    }
+
     auto pathPtrReader = sectionSubReader(*zimReader,
                                           "Dirent pointer table",
                                           offset_t(header.getPathPtrPos()),
@@ -297,10 +306,6 @@ class Grouping
         throw ZimFileFormatError("last cluster offset larger than file size; file corrupt");
       }
     }
-
-    if (header.hasChecksum() && header.getChecksumPos() != (getFilesize().v-16) ) {
-      throw ZimFileFormatError("Checksum position is not valid");
-    }
   }
 
   offset_type FileImpl::getMimeListEndUpperLimit() const

test/archive.cpp

@@ -264,6 +264,31 @@ TEST(ZimArchive, openRealZimArchive)
   }
 }
 
+TEST(ZimArchive, openSplitZimArchive)
+{
+  const char* fname = "wikibooks_be_all_nopic_2017-02_splitted.zim";
+
+  for (auto& testfile: getDataFilePath(fname)) {
+    const TestContext ctx{ {"path", testfile.path+"aa" } };
+    std::unique_ptr<zim::Archive> archive;
+    EXPECT_NO_THROW( archive.reset(new zim::Archive(testfile.path+"aa")) ) << ctx;
+    if ( archive ) {
+      EXPECT_TRUE( archive->check() ) << ctx;
+    }
+  }
+}
+
+TEST(ZimArchive, openDontFallbackOnNonSplitZimArchive)
+{
+  const char* fname = "wikibooks_be_all_nopic_2017-02.zim";
+
+  for (auto& testfile: getDataFilePath(fname)) {
+    const TestContext ctx{ {"path", testfile.path+"aa" } };
+    std::unique_ptr<zim::Archive> archive;
+    EXPECT_THROW( archive.reset(new zim::Archive(testfile.path+"aa")), std::runtime_error) << ctx;
+  }
+}
+
 TEST(ZimArchive, randomEntry)
 {
   const char* const zimfiles[] = {
@@ -434,7 +459,7 @@ TEST(ZimArchive, validate)
 
   TEST_BROKEN_ZIM_NAME(
     "invalid.invalid_checksumpos.zim",
-    "Checksum position is not valid\n"
+    "Zim file(s) is of bad size or corrupted.\n"
   );
 
   TEST_BROKEN_ZIM_NAME(