refactor:do some internal refactor.

source/util/src/tpagedbuf.c

@@ -6,6 +6,9 @@
 #include "tlog.h"
 
 #define GET_PAYLOAD_DATA(_p)          ((char*)(_p)->pData + POINTER_BYTES)
+#define BUF_PAGE_IN_MEM(_p)           ((_p)->pData != NULL)
+#define CLEAR_BUF_PAGE_IN_MEM_FLAG(_p) ((_p)->pData = NULL)
+#define HAS_DATA_IN_DISK(_p)          ((_p)->offset >= 0)
 #define NO_IN_MEM_AVAILABLE_PAGES(_b) (listNEles((_b)->lruList) >= (_b)->inMemPages)
 
 typedef struct SPageDiskInfo {
@@ -14,7 +17,7 @@ typedef struct SPageDiskInfo {
 } SPageDiskInfo, SFreeListItem;
 
 struct SPageInfo {
-  SListNode* pn;  // point to list node struct
+  SListNode* pn;         // point to list node struct. it is NULL when the page is evicted from the in-memory buffer
   void*      pData;
   int64_t    offset;
   int32_t    pageId;
@@ -112,8 +115,6 @@ static uint64_t allocateNewPositionInFile(SDiskbasedBuf* pBuf, size_t size) {
   }
 }
 
-static void setPageNotInBuf(SPageInfo* pPageInfo) { pPageInfo->pData = NULL; }
-
 /**
  *   +--------------------------+-------------------+--------------+
  *   | PTR to SPageInfo (8bytes)| Payload (PageSize)| 2 Extra Bytes|
@@ -134,17 +135,18 @@ static char* doFlushBufPage(SDiskbasedBuf* pBuf, SPageInfo* pg) {
 
   int32_t size = pBuf->pageSize;
   char*   t = NULL;
-  if (pg->offset == -1 || pg->dirty) {
+  if ((!HAS_DATA_IN_DISK(pg)) || pg->dirty) {
     void* payload = GET_PAYLOAD_DATA(pg);
     t = doCompressData(payload, pBuf->pageSize, &size, pBuf);
-    ASSERTS(size >= 0, "size is negative");
+    if (size < 0) {
+      uError("failed to compress data when flushing data to disk, %s", pBuf->id);
+      return NULL;
+    }
   }
 
   // this page is flushed to disk for the first time
   if (pg->dirty) {
-    if (pg->offset == -1) {
-      ASSERTS(pg->dirty == true, "pg->dirty is false");
-
+    if (!HAS_DATA_IN_DISK(pg)) {
       pg->offset = allocateNewPositionInFile(pBuf, size);
       pBuf->nextPos += size;
 
@@ -160,6 +162,7 @@ static char* doFlushBufPage(SDiskbasedBuf* pBuf, SPageInfo* pg) {
         return NULL;
       }
 
+      // extend the file size
       if (pBuf->fileSize < pg->offset + size) {
         pBuf->fileSize = pg->offset + size;
       }
@@ -202,13 +205,13 @@ static char* doFlushBufPage(SDiskbasedBuf* pBuf, SPageInfo* pg) {
     size = pg->length;
   }
 
-  ASSERT(size > 0 || (pg->offset == -1 && pg->length == -1));
-
   char* pDataBuf = pg->pData;
   memset(pDataBuf, 0, getAllocPageSize(pBuf->pageSize));
+
 #ifdef BUF_PAGE_DEBUG
   uDebug("page_flush %p, pageId:%d, offset:%d", pDataBuf, pg->pageId, pg->offset);
 #endif
+
   pg->length = size;  // on disk size
   return pDataBuf;
 }
@@ -224,13 +227,19 @@ static char* flushBufPage(SDiskbasedBuf* pBuf, SPageInfo* pg) {
   }
 
   char* p = doFlushBufPage(pBuf, pg);
-  setPageNotInBuf(pg);
+  CLEAR_BUF_PAGE_IN_MEM_FLAG(pg);
+
   pg->dirty = false;
   return p;
 }
 
 // load file block data in disk
 static int32_t loadPageFromDisk(SDiskbasedBuf* pBuf, SPageInfo* pg) {
+  if (pg->offset < 0 || pg->length <= 0) {
+    uError("failed to load buf page from disk, offset:%"PRId64", length:%d, %s", pg->offset, pg->length, pBuf->id);
+    return TSDB_CODE_INVALID_PARA;
+  }
+
   int32_t ret = taosLSeekFile(pBuf->pFile, pg->offset, SEEK_SET);
   if (ret == -1) {
     ret = TAOS_SYSTEM_ERROR(errno);
@@ -252,7 +261,7 @@ static int32_t loadPageFromDisk(SDiskbasedBuf* pBuf, SPageInfo* pg) {
   return 0;
 }
 
-static SPageInfo* registerPage(SDiskbasedBuf* pBuf, int32_t pageId) {
+static SPageInfo* registerNewPageInfo(SDiskbasedBuf* pBuf, int32_t pageId) {
   pBuf->numOfPages += 1;
 
   SPageInfo* ppi = taosMemoryMalloc(sizeof(SPageInfo));
@@ -279,7 +288,9 @@ static SListNode* getEldestUnrefedPage(SDiskbasedBuf* pBuf) {
   SListNode* pn = NULL;
   while ((pn = tdListNext(&iter)) != NULL) {
     SPageInfo* pageInfo = *(SPageInfo**)pn->data;
-    ASSERT(pageInfo->pageId >= 0 && pageInfo->pn == pn);
+
+    SPageInfo* p = *(SPageInfo**)(pageInfo->pData);
+    ASSERT(pageInfo->pageId >= 0 && pageInfo->pn == pn && p == pageInfo);
 
     if (!pageInfo->used) {
       break;
@@ -299,7 +310,6 @@ static char* evictBufPage(SDiskbasedBuf* pBuf) {
   tdListPopNode(pBuf->lruList, pn);
 
   SPageInfo* d = *(SPageInfo**)pn->data;
-  ASSERTS(d->pn == pn, "d->pn not equal pn");
 
   d->pn = NULL;
   taosMemoryFreeClear(pn);
@@ -422,7 +432,7 @@ void* getNewBufPage(SDiskbasedBuf* pBuf, int32_t* pageId) {
     *pageId = (++pBuf->allocateId);
 
     // register page id info
-    pi = registerPage(pBuf, *pageId);
+    pi = registerNewPageInfo(pBuf, *pageId);
     if (pi == NULL) {
       return NULL;
     }
@@ -446,15 +456,21 @@ void* getNewBufPage(SDiskbasedBuf* pBuf, int32_t* pageId) {
 
 void* getBufPage(SDiskbasedBuf* pBuf, int32_t id) {
   if (id < 0) {
+    terrno = TSDB_CODE_INVALID_PARA;
+    uError("invalid page id:%d, %s", id, pBuf->id);
     return NULL;
   }
 
   pBuf->statis.getPages += 1;
 
   SPageInfo** pi = taosHashGet(pBuf->all, &id, sizeof(int32_t));
-  ASSERT(pi != NULL && *pi != NULL);
+  if (pi == NULL || *pi == NULL) {
+    uError("failed to locate the buffer page:%d, %s", id, pBuf->id);
+    terrno = TSDB_CODE_INVALID_PARA;
+    return NULL;
+  }
 
-  if ((*pi)->pData != NULL) {  // it is in memory
+  if (BUF_PAGE_IN_MEM(*pi)) {  // it is in memory
     // no need to update the LRU list if only one page exists
     if (pBuf->numOfPages == 1) {
       (*pi)->used = true;
@@ -462,7 +478,10 @@ void* getBufPage(SDiskbasedBuf* pBuf, int32_t id) {
     }
 
     SPageInfo** pInfo = (SPageInfo**)((*pi)->pn->data);
-    ASSERT(*pInfo == *pi);
+    if (*pInfo != *pi) {
+      uError("inconsistently data in paged buffer, pInfo:%p, pi:%p, %s", *pInfo, *pi, pBuf->id);
+      return NULL;
+    }
 
     lruListMoveToFront(pBuf->lruList, (*pi));
     (*pi)->used = true;
@@ -472,10 +491,12 @@ void* getBufPage(SDiskbasedBuf* pBuf, int32_t id) {
 #endif
     return (void*)(GET_PAYLOAD_DATA(*pi));
   } else {  // not in memory
-    ASSERT((*pi)->pData == NULL && (*pi)->pn == NULL &&
+    ASSERT((!BUF_PAGE_IN_MEM(*pi)) && (*pi)->pn == NULL &&
            (((*pi)->length >= 0 && (*pi)->offset >= 0) || ((*pi)->length == -1 && (*pi)->offset == -1)));
 
     (*pi)->pData = doExtractPage(pBuf);
+
+    // failed to evict buffer page, return with error code.
     if ((*pi)->pData == NULL) {
       return NULL;
     }
@@ -487,7 +508,7 @@ void* getBufPage(SDiskbasedBuf* pBuf, int32_t id) {
     (*pi)->used = true;
 
     // some data has been flushed to disk, and needs to be loaded into buffer again.
-    if ((*pi)->length > 0 && (*pi)->offset >= 0) {
+    if (HAS_DATA_IN_DISK(*pi)) {
       int32_t code = loadPageFromDisk(pBuf, *pi);
       if (code != 0) {
         terrno = code;