stos: ob: Add directory object operations

This commit adds operations for appending directories and top-level
lookups.

Signed-off-by: Chloe M. <chloe@mensia.org>

paw/stos/head/ob/object.h

@@ -35,6 +35,7 @@ typedef enum {
  * @Type:       Object type
  * @Data:       Object data
  * @CacheNext:  Used when reclaiming object
+ * @DirecNext:  Directory link
  */
 typedef struct _ST_OBJECT {
     CHAR Name[OBJECT_NAMESZ];
@@ -42,6 +43,7 @@ typedef struct _ST_OBJECT {
     OBJECT_TYPE Type;
     VOID *Data;
     struct _ST_OBJECT *CacheNext;
+    struct _ST_OBJECT *DirecNext;
 } ST_OBJECT;
 
 /*
@@ -66,6 +68,14 @@ typedef struct {
  */
 ST_STATUS ObCreateDirectory(const CHAR *Name, ST_OBJECT **Result);
 
+/*
+ * Append an object to a directory
+ *
+ * @DirecParent: Parent of directory to append to
+ * @Object:      Object to append to directory
+ */
+ST_STATUS ObAppendDirectory(ST_OBJECT *DirecParent, ST_OBJECT *Object);
+
 /*
  * Allocate and create a new objec
  *
@@ -84,6 +94,15 @@ ST_STATUS ObCreateObject(
  */
 VOID ObInitManager(VOID);
 
+/*
+ * Look up an object from a parent directory
+ *
+ * @Parent: Parent directly to look up from
+ * @Name:   Name of object to lookup
+ * @Result: Result is written here
+ */
+ST_STATUS ObLookupFromTop(ST_OBJECT *Parent, const CHAR *Name, ST_OBJECT **Result);
+
 /*
  * Reclaim an object after use, if its reference count is > 1, simply
  * bump it down. Once it hits zero, the object is returned to the cache.

paw/stos/ob/ob.c

@@ -104,3 +104,83 @@ ObReclaimObject(ST_OBJECT *Object)
         ObReclaimToCache(&gObCache, Object);
     }
 }
+
+ST_STATUS
+ObAppendDirectory(ST_OBJECT *DirecParent, ST_OBJECT *Object)
+{
+    OBJECT_DIRECTORY *Directory;
+    ST_OBJECT *Last;
+
+    if (DirecParent == NULL || Object == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    if (DirecParent->Type != OBJECT_TYPE_DIRECTORY) {
+        return STATUS_NOT_DIRECTORY;
+    }
+
+    Directory = DirecParent->Data;
+    if (Directory == NULL) {
+        return STATUS_IO_ERROR;
+    }
+
+    /* TODO: Place lock here */
+    if (Directory->First == NULL || Directory->Last == NULL) {
+        Directory->First = Object;
+        Directory->Last = Object;
+    } else {
+        Last = Directory->Last;
+        Last->DirecNext = Object;
+        Directory->Last = Object;
+    }
+
+    return STATUS_SUCCESS;
+}
+
+ST_STATUS
+ObLookupFromTop(ST_OBJECT *Parent, const CHAR *Name, ST_OBJECT **Result)
+{
+    ST_OBJECT *Entry;
+    OBJECT_DIRECTORY *ParentDirec;
+    USIZE NameLen;
+
+    if (Parent == NULL || Name == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    if (Result == NULL) {
+        return STATUS_INVALID_PARAM;
+    }
+
+    /* Must be a directory */
+    if (Parent->Type != OBJECT_TYPE_DIRECTORY) {
+        return STATUS_NOT_DIRECTORY;
+    }
+
+    ParentDirec = Parent->Data;
+    if (ParentDirec == NULL) {
+        return STATUS_IO_ERROR;
+    }
+
+    Entry = ParentDirec->First;
+    NameLen = RtlStrLen(Name);
+    if (NameLen >= OBJECT_NAMESZ - 1) {
+        return STATUS_NAME_TOO_LONG;
+    }
+
+    while (Entry != NULL) {
+        if (*Entry->Name != *Name) {
+            Entry = Entry->DirecNext;
+            continue;
+        }
+
+        if (RtlMemCmp(Entry->Name, Name, NameLen) == 0) {
+            *Result = Entry;
+            return STATUS_SUCCESS;
+        }
+
+        Entry = Entry->DirecNext;
+    }
+
+    return STATUS_NOT_FOUND;
+}