From cebef7b2b36567b9b980b227277dd6e83fee838e Mon Sep 17 00:00:00 2001
From: Hongze Cheng <hzcheng@taosdata.com>
Date: Thu, 3 Mar 2022 09:03:24 +0000
Subject: [PATCH] more TDB

---
 source/libs/tdb/src/db/tdbBtree.c  | 42 +++++++++++++++++++++++++++---
 source/libs/tdb/src/db/tdbDb.c     |  2 +-
 source/libs/tdb/src/db/tdbPager.c  | 18 -------------
 source/libs/tdb/src/inc/tdbBtree.h |  2 +-
 source/libs/tdb/src/inc/tdbPager.h |  2 ++
 5 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/source/libs/tdb/src/db/tdbBtree.c b/source/libs/tdb/src/db/tdbBtree.c
index a59a1b90f5..b31253149e 100644
--- a/source/libs/tdb/src/db/tdbBtree.c
+++ b/source/libs/tdb/src/db/tdbBtree.c
@@ -40,9 +40,11 @@ static int tdbBtCursorMoveToRoot(SBtCursor *pCur);
 static int tdbInitBtPage(SPage *pPage, SBtPage **ppBtPage);
 static int tdbCompareKeyAndCell(const void *pKey, int kLen, const void *pCell);
 static int tdbDefaultKeyCmprFn(const void *pKey1, int keyLen1, const void *pKey2, int keyLen2);
+static int tdbBtreeOpenImpl(SBTree *pBt);
 
-int tdbBtreeOpen(SPgno rtPgno, int keyLen, int valLen, SPager *pPager, FKeyComparator kcmpr, SBTree **ppBt) {
+int tdbBtreeOpen(int keyLen, int valLen, SPager *pPager, FKeyComparator kcmpr, SBTree **ppBt) {
   SBTree *pBt;
+  int     ret;
 
   *ppBt = NULL;
 
@@ -51,8 +53,6 @@ int tdbBtreeOpen(SPgno rtPgno, int keyLen, int valLen, SPager *pPager, FKeyCompa
     return -1;
   }
 
-  // pBt->root
-  pBt->root = rtPgno;
   // pBt->keyLen
   pBt->keyLen = keyLen;
   // pBt->valLen
@@ -79,6 +79,13 @@ int tdbBtreeOpen(SPgno rtPgno, int keyLen, int valLen, SPager *pPager, FKeyCompa
   // pBt->minLeaf
   pBt->minLeaf = pBt->minLocal;
 
+  // TODO: pBt->root
+  ret = tdbBtreeOpenImpl(pBt);
+  if (ret < 0) {
+    free(pBt);
+    return -1;
+  }
+
   *ppBt = pBt;
   return 0;
 }
@@ -268,4 +275,33 @@ static int tdbDefaultKeyCmprFn(const void *pKey1, int keyLen1, const void *pKey2
     }
   }
   return cret;
+}
+
+static int tdbBtreeOpenImpl(SBTree *pBt) {
+  // Try to get the root page of the an existing btree
+
+  SPgno  pgno;
+  SPage *pPage;
+  int    ret;
+
+  {
+    // TODO: Search the main DB to check if the DB exists
+    pgno = 0;
+  }
+
+  if (pgno != 0) {
+    pBt->root = pgno;
+    return 0;
+  }
+
+  // Try to create a new database
+  ret = tdbPagerNewPage(pBt->pPager, &pgno, &pPage);
+  if (ret < 0) {
+    return -1;
+  }
+
+  ASSERT(pgno != 0);
+  pBt->root = pgno;
+
+  return 0;
 }
\ No newline at end of file
diff --git a/source/libs/tdb/src/db/tdbDb.c b/source/libs/tdb/src/db/tdbDb.c
index 51b654cc86..e87c57e547 100644
--- a/source/libs/tdb/src/db/tdbDb.c
+++ b/source/libs/tdb/src/db/tdbDb.c
@@ -50,7 +50,7 @@ int tdbDbOpen(const char *fname, int keyLen, int valLen, FKeyComparator keyCmprF
   ASSERT(pPager != NULL);
 
   // pDb->pBt
-  ret = tdbBtreeOpen(pgno, keyLen, valLen, pPager, keyCmprFn, &(pDb->pBt));
+  ret = tdbBtreeOpen(keyLen, valLen, pPager, keyCmprFn, &(pDb->pBt));
   if (ret < 0) {
     return -1;
   }
diff --git a/source/libs/tdb/src/db/tdbPager.c b/source/libs/tdb/src/db/tdbPager.c
index ab750665ff..0a5a8abe82 100644
--- a/source/libs/tdb/src/db/tdbPager.c
+++ b/source/libs/tdb/src/db/tdbPager.c
@@ -187,24 +187,6 @@ int tdbPagerWrite(SPager *pPager, SPage *pPage) {
   return 0;
 }
 
-// int tdbPagerAllocPage(SPager *pPager, SPage **ppPage, SPgno *ppgno) {
-//   SPage *pPage;
-//   SPgno  pgno;
-
-//   if (1 /*TODO: no free page*/) {
-//     pgno = ++pPager->dbFileSize;
-//     pPage = tdbPagerGet(pPager, pgno, false);
-//     ASSERT(pPage != NULL);
-//   } else {
-//     /* TODO: allocate from the free list */
-//     ASSERT(0);
-//   }
-
-//   *ppPage = pPage;
-//   *ppgno = pgno;
-//   return 0;
-// }
-
 int tdbPagerBegin(SPager *pPager) {
   if (pPager->inTran) {
     return 0;
diff --git a/source/libs/tdb/src/inc/tdbBtree.h b/source/libs/tdb/src/inc/tdbBtree.h
index 8b0fadd507..64b3dbeaa9 100644
--- a/source/libs/tdb/src/inc/tdbBtree.h
+++ b/source/libs/tdb/src/inc/tdbBtree.h
@@ -34,7 +34,7 @@ struct SBtCursor {
   void *   pBuf;
 };
 
-int tdbBtreeOpen(SPgno rtPgno, int keyLen, int valLen, SPager *pFile, FKeyComparator kcmpr, SBTree **ppBt);
+int tdbBtreeOpen(int keyLen, int valLen, SPager *pFile, FKeyComparator kcmpr, SBTree **ppBt);
 int tdbBtreeClose(SBTree *pBt);
 int tdbBtreeCursor(SBtCursor *pCur, SBTree *pBt);
 int tdbBtCursorInsert(SBtCursor *pCur, const void *pKey, int kLen, const void *pVal, int vLen);
diff --git a/source/libs/tdb/src/inc/tdbPager.h b/source/libs/tdb/src/inc/tdbPager.h
index 8eb1bfe105..a32439f30f 100644
--- a/source/libs/tdb/src/inc/tdbPager.h
+++ b/source/libs/tdb/src/inc/tdbPager.h
@@ -28,6 +28,8 @@ int    tdbPagerWrite(SPager *pPager, SPage *pPage);
 int    tdbPagerBegin(SPager *pPager);
 int    tdbPagerCommit(SPager *pPager);
 int    tdbPagerGetPageSize(SPager *pPager);
+int    tdbPagerFetchPage(SPager *pPager, SPgno pgno, SPage **ppPage);
+int    tdbPagerNewPage(SPager *pPager, SPgno *ppgno, SPage **ppPage);
 
 #ifdef __cplusplus
 }