Merge pull request #70 from Henneberg-Systemdesign/support-for-get-partial-object

Support for get partial object

src/simple-mtpfs-fuse.cpp

@@ -596,11 +596,19 @@ int SMTPFileSystem::open(const char *path, struct fuse_file_info *file_info)
     } else {
         tmp_path = m_tmp_files_pool.makeTmpPath(std_path);
 
-        int rval = m_device.filePull(std_path, tmp_path);
-        if (rval != 0)
-            return -rval;
+        // only copy the file if needed
+        if (!hasPartialObjectSupport()) {
+            int rval = m_device.filePull(std_path, tmp_path);
+            if (rval != 0)
+                return -rval;
+        } else {
+            int fd = ::creat(tmp_path.c_str(), S_IRUSR | S_IWUSR);
+            ::close(fd);
+        }
     }
 
+    // we create the tmp file even if we can use partial get/send to
+    // have a valid file descriptor
     int fd = ::open(tmp_path.c_str(), file_info->flags);
     if (fd < 0) {
         ::unlink(tmp_path.c_str());
@@ -620,24 +628,38 @@ int SMTPFileSystem::open(const char *path, struct fuse_file_info *file_info)
 int SMTPFileSystem::read(const char *path, char *buf, size_t size,
     off_t offset, struct fuse_file_info *file_info)
 {
-    int rval = ::pread(file_info->fh, buf, size, offset);
-    if (rval < 0)
-        return -errno;
+    int rval = 0;
+    if (hasPartialObjectSupport()) {
+        const std::string std_path(path);
+        rval = m_device.fileRead(std_path, buf, size, offset);
+    } else {
+        rval = ::pread(file_info->fh, buf, size, offset);
+        if (rval < 0)
+            return -errno;
+    }
+
     return rval;
 }
 
 int SMTPFileSystem::write(const char *path, const char *buf, size_t size,
     off_t offset, struct fuse_file_info *file_info)
 {
-    const TypeTmpFile *tmp_file = m_tmp_files_pool.getFile(std::string(path));
-    if (!tmp_file)
-        return -EINVAL;
+    int rval = 0;
+    if (hasPartialObjectSupport()) {
+        const std::string std_path(path);
+        rval = m_device.fileWrite(std_path, buf, size, offset);
+    } else {
+        const TypeTmpFile *tmp_file = m_tmp_files_pool.getFile(std::string(path));
+        if (!tmp_file)
+            return -EINVAL;
 
-    int rval = ::pwrite(file_info->fh, buf, size, offset);
-    if (rval < 0)
-        return -errno;
+        rval = ::pwrite(file_info->fh, buf, size, offset);
+        if (rval < 0)
+            return -errno;
+
+        const_cast<TypeTmpFile*>(tmp_file)->setModified();
+    }
 
-    const_cast<TypeTmpFile*>(tmp_file)->setModified();
     return rval;
 }
 
@@ -764,3 +786,9 @@ int SMTPFileSystem::ftruncate(const char *path, off_t offset,
     const_cast<TypeTmpFile*>(tmp_file)->setModified();
     return 0;
 }
+
+bool SMTPFileSystem::hasPartialObjectSupport()
+{
+    MTPDevice::Capabilities caps = m_device.getCapabilities();
+    return (caps.canGetPartialObject() && caps.canSendPartialObject());
+}

src/simple-mtpfs-fuse.h

@@ -104,10 +104,7 @@ public:
     int create(const char *path, mode_t mode, fuse_file_info *file_info);
 
 private:
-    static bool removeDir(const std::string &dirname);
-
-    bool createTmpDir();
-    bool removeTmpDir();
+    bool hasPartialObjectSupport();
 
     static std::unique_ptr<SMTPFileSystem> s_instance;
     struct fuse_args m_args;

src/simple-mtpfs-mtp-device.cpp

@@ -467,6 +467,64 @@ int MTPDevice::rename(const std::string &oldpath, const std::string &newpath)
 #endif
 }
 
+int MTPDevice::fileRead(const std::string &path, char *buf, size_t size,
+    off_t offset)
+{
+    const std::string path_basename(smtpfs_basename(path));
+    const std::string path_dirname(smtpfs_dirname(path));
+    const TypeDir *dir_parent = dirFetchContent(path_dirname);
+    const TypeFile *file_to_fetch = dir_parent ?
+        dir_parent->file(path_basename) : nullptr;
+    if (!dir_parent) {
+        logerr("Can not fetch '", path, "'.\n");
+        return -EINVAL;
+    }
+    if (!file_to_fetch) {
+        logerr("No such file '", path, "'.\n");
+        return -ENOENT;
+    }
+
+    // all systems clear
+    unsigned char *tmp_buf;
+    unsigned int tmp_size;
+    int rval = LIBMTP_GetPartialObject(m_device, file_to_fetch->id(),
+        offset, size, &tmp_buf, &tmp_size);
+    if (tmp_size > 0) {
+        memcpy(buf, tmp_buf, tmp_size);
+        free(tmp_buf);
+    }
+
+    if (rval != 0)
+        return -EIO;
+    return tmp_size;
+}
+
+int MTPDevice::fileWrite(const std::string &path, const char *buf, size_t size,
+    off_t offset)
+{
+    const std::string path_basename(smtpfs_basename(path));
+    const std::string path_dirname(smtpfs_dirname(path));
+    const TypeDir *dir_parent = dirFetchContent(path_dirname);
+    const TypeFile *file_to_fetch = dir_parent ?
+        dir_parent->file(path_basename) : nullptr;
+    if (!dir_parent) {
+        logerr("Can not fetch '", path, "'.\n");
+        return -EINVAL;
+    }
+    if (!file_to_fetch) {
+        logerr("No such file '", path, "'.\n");
+        return -ENOENT;
+    }
+
+    // all systems clear
+    int rval = LIBMTP_SendPartialObject(m_device, file_to_fetch->id(),
+        offset, (unsigned char *) buf, size);
+
+    if (rval < 0)
+        return -EIO;
+    return size;
+}
+
 int MTPDevice::filePull(const std::string &src, const std::string &dst)
 {
     const std::string src_basename(smtpfs_basename(src));

src/simple-mtpfs-mtp-device.h

@@ -78,6 +78,8 @@ public:
 
     int rename(const std::string &oldpath, const std::string &newpath);
 
+    int fileRead(const std::string &path, char *buf, size_t size, off_t offset);
+    int fileWrite(const std::string &path, const char *buf, size_t size, off_t offset);
     int filePull(const std::string &src, const std::string &dst);
     int filePush(const std::string &src, const std::string &dst);
     int fileRemove(const std::string &path);