Fix a _whole_ pile of bugs in the HFS plugin, and get it to produce meaningful

error messages.

lib/utils.cc

@@ -76,10 +76,10 @@ bool endsWith(const std::string& value, const std::string& ending)
 
 std::string toUpper(const std::string& value)
 {
-	std::string s = value;
-	for (char& c : s)
-		c = toupper(c);
-	return s;
+    std::string s = value;
+    for (char& c : s)
+        c = toupper(c);
+    return s;
 }
 
 std::string leftTrimWhitespace(std::string value)

lib/vfs/fluxsectorinterface.cc

@@ -94,8 +94,12 @@ public:
 
         /* We now have complete tracks which can be written. */
 
-        writeDiskCommand(
-            _changedSectors, *_encoder, *_fluxSink, &*_decoder, &*_fluxSource, locations);
+        writeDiskCommand(_changedSectors,
+            *_encoder,
+            *_fluxSink,
+            &*_decoder,
+            &*_fluxSource,
+            locations);
 
         discardChanges();
     }

lib/vfs/machfs.cc

@@ -27,7 +27,7 @@ public:
     uint32_t capabilities() const
     {
         return OP_GETFSDATA | OP_CREATE | OP_LIST | OP_GETFILE | OP_PUTFILE |
-               OP_GETDIRENT | OP_MOVE | OP_CREATEDIR;
+               OP_GETDIRENT | OP_MOVE | OP_CREATEDIR | OP_DELETE;
     }
 
     std::map<std::string, std::string> getMetadata() override
@@ -58,8 +58,13 @@ public:
         if (!quick)
             eraseEverythingOnDisk();
 
-        hfs_format(
-            (const char*)this, 0, HFS_MODE_ANY, volumeName.c_str(), 0, nullptr);
+        if (hfs_format((const char*)this,
+                0,
+                HFS_MODE_ANY,
+                volumeName.c_str(),
+                0,
+                nullptr))
+            throwError();
     }
 
     std::vector<std::shared_ptr<Dirent>> list(const Path& path) override
@@ -70,7 +75,7 @@ public:
         auto pathstr = ":" + path.to_str(":");
         HfsDir dir(hfs_opendir(_vol, pathstr.c_str()));
         if (!dir)
-            throw FileNotFoundException();
+            throwError();
 
         for (;;)
         {
@@ -94,7 +99,7 @@ public:
         auto pathstr = ":" + path.to_str(":");
         hfsdirent de;
         if (hfs_stat(_vol, pathstr.c_str(), &de))
-            throw FileNotFoundException();
+            throwError();
 
         return toDirent(de, path.parent());
     }
@@ -109,7 +114,7 @@ public:
         auto pathstr = ":" + path.to_str(":");
         HfsFile file(hfs_open(_vol, pathstr.c_str()));
         if (!file)
-            throw FileNotFoundException();
+            throwError();
 
         AppleSingle a;
 
@@ -150,7 +155,7 @@ public:
             (const char*)a.type.cbegin(),
             (const char*)a.creator.cbegin()));
         if (!file)
-            throw CannotWriteException();
+            throwError();
 
         hfs_setfork(file, 0);
         writeBytes(file, a.data);
@@ -165,8 +170,8 @@ public:
             throw BadPathException();
 
         auto pathstr = ":" + path.to_str(":");
-        if (!hfs_delete(_vol, pathstr.c_str()))
-            throw CannotWriteException();
+        if (hfs_delete(_vol, pathstr.c_str()))
+            throwError();
     }
 
     void moveFile(const Path& oldPath, const Path& newPath) override
@@ -177,8 +182,8 @@ public:
 
         auto oldPathStr = ":" + oldPath.to_str(":");
         auto newPathStr = ":" + newPath.to_str(":");
-        if (!hfs_rename(_vol, oldPathStr.c_str(), newPathStr.c_str()))
-            throw CannotWriteException();
+        if (hfs_rename(_vol, oldPathStr.c_str(), newPathStr.c_str()))
+            throwError();
     }
 
     void createDirectory(const Path& path) override
@@ -186,8 +191,8 @@ public:
         HfsMount m(this);
 
         auto pathStr = ":" + path.to_str(":");
-        if (!hfs_mkdir(_vol, pathStr.c_str()))
-            throw CannotWriteException();
+        if (hfs_mkdir(_vol, pathStr.c_str()))
+            throwError();
     }
 
 private:
@@ -248,6 +253,56 @@ private:
         return dirent;
     }
 
+    void throwError()
+    {
+        auto message =
+            fmt::format("HFS error: {}", hfs_error ? hfs_error : "unknown");
+        switch (errno)
+        {
+            case ENOTDIR:
+            case ENAMETOOLONG:
+                if (hfs_error)
+                    throw BadPathException(message);
+                else
+                    throw BadPathException();
+
+            case ENOENT:
+                if (hfs_error)
+                    throw FileNotFoundException(message);
+                else
+                    throw FileNotFoundException();
+
+            case EEXIST:
+                throw BadPathException("That already exists");
+
+            case ENOTEMPTY:
+                throw BadPathException("Directory is not empty");
+
+            case EISDIR:
+                throw BadPathException("That's a directory");
+
+            case EIO:
+            case EINVAL:
+                if (hfs_error)
+                    throw BadFilesystemException(message);
+                else
+                    throw BadFilesystemException();
+
+            case ENOSPC:
+            case ENOMEM:
+                if (hfs_error)
+                    throw DiskFullException(message);
+                else
+                    throw DiskFullException();
+
+            case EROFS:
+                if (hfs_error)
+                    throw ReadOnlyFilesystemException(message);
+                else
+                    throw ReadOnlyFilesystemException();
+        }
+    }
+
 private:
     Bytes readBytes(hfsfile* file)
     {

lib/vfs/vfs.h

@@ -59,24 +59,40 @@ class BadPathException : public FilesystemException
 {
 public:
     BadPathException(): FilesystemException("Bad path") {}
+
+    BadPathException(const std::string& msg): FilesystemException(msg) {}
 };
 
 class FileNotFoundException : public FilesystemException
 {
 public:
     FileNotFoundException(): FilesystemException("File not found") {}
+
+    FileNotFoundException(const std::string& msg): FilesystemException(msg) {}
 };
 
 class BadFilesystemException : public FilesystemException
 {
 public:
     BadFilesystemException(): FilesystemException("Invalid filesystem") {}
+
+    BadFilesystemException(const std::string& msg): FilesystemException(msg) {}
 };
 
 class CannotWriteException : public FilesystemException
 {
 public:
     CannotWriteException(): FilesystemException("Cannot write file") {}
+
+    CannotWriteException(const std::string& msg): FilesystemException(msg) {}
+};
+
+class DiskFullException : public CannotWriteException
+{
+public:
+    DiskFullException(): CannotWriteException("Disk is full") {}
+
+    DiskFullException(const std::string& msg): CannotWriteException(msg) {}
 };
 
 class ReadOnlyFilesystemException : public FilesystemException
@@ -85,6 +101,11 @@ public:
     ReadOnlyFilesystemException(): FilesystemException("Read only filesystem")
     {
     }
+
+    ReadOnlyFilesystemException(const std::string& msg):
+        FilesystemException(msg)
+    {
+    }
 };
 
 class UnimplementedFilesystemException : public FilesystemException