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-rw-r--r--src/os_kv.c979
1 files changed, 979 insertions, 0 deletions
diff --git a/src/os_kv.c b/src/os_kv.c
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--- /dev/null
+++ b/src/os_kv.c
@@ -0,0 +1,979 @@
+/*
+** 2022-09-06
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file contains an experimental VFS layer that operates on a
+** Key/Value storage engine where both keys and values must be pure
+** text.
+*/
+#include <sqliteInt.h>
+#if SQLITE_OS_KV || (SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL))
+
+/*****************************************************************************
+** Debugging logic
+*/
+
+/* SQLITE_KV_TRACE() is used for tracing calls to kvstorage routines. */
+#if 0
+#define SQLITE_KV_TRACE(X) printf X
+#else
+#define SQLITE_KV_TRACE(X)
+#endif
+
+/* SQLITE_KV_LOG() is used for tracing calls to the VFS interface */
+#if 0
+#define SQLITE_KV_LOG(X) printf X
+#else
+#define SQLITE_KV_LOG(X)
+#endif
+
+
+/*
+** Forward declaration of objects used by this VFS implementation
+*/
+typedef struct KVVfsFile KVVfsFile;
+
+/* A single open file. There are only two files represented by this
+** VFS - the database and the rollback journal.
+*/
+struct KVVfsFile {
+ sqlite3_file base; /* IO methods */
+ const char *zClass; /* Storage class */
+ int isJournal; /* True if this is a journal file */
+ unsigned int nJrnl; /* Space allocated for aJrnl[] */
+ char *aJrnl; /* Journal content */
+ int szPage; /* Last known page size */
+ sqlite3_int64 szDb; /* Database file size. -1 means unknown */
+ char *aData; /* Buffer to hold page data */
+};
+#define SQLITE_KVOS_SZ 133073
+
+/*
+** Methods for KVVfsFile
+*/
+static int kvvfsClose(sqlite3_file*);
+static int kvvfsReadDb(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsReadJrnl(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int kvvfsWriteDb(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsWriteJrnl(sqlite3_file*,const void*,int iAmt, sqlite3_int64);
+static int kvvfsTruncateDb(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsTruncateJrnl(sqlite3_file*, sqlite3_int64 size);
+static int kvvfsSyncDb(sqlite3_file*, int flags);
+static int kvvfsSyncJrnl(sqlite3_file*, int flags);
+static int kvvfsFileSizeDb(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsFileSizeJrnl(sqlite3_file*, sqlite3_int64 *pSize);
+static int kvvfsLock(sqlite3_file*, int);
+static int kvvfsUnlock(sqlite3_file*, int);
+static int kvvfsCheckReservedLock(sqlite3_file*, int *pResOut);
+static int kvvfsFileControlDb(sqlite3_file*, int op, void *pArg);
+static int kvvfsFileControlJrnl(sqlite3_file*, int op, void *pArg);
+static int kvvfsSectorSize(sqlite3_file*);
+static int kvvfsDeviceCharacteristics(sqlite3_file*);
+
+/*
+** Methods for sqlite3_vfs
+*/
+static int kvvfsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int kvvfsDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int kvvfsAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int kvvfsFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *kvvfsDlOpen(sqlite3_vfs*, const char *zFilename);
+static int kvvfsRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int kvvfsSleep(sqlite3_vfs*, int microseconds);
+static int kvvfsCurrentTime(sqlite3_vfs*, double*);
+static int kvvfsCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs sqlite3OsKvvfsObject = {
+ 1, /* iVersion */
+ sizeof(KVVfsFile), /* szOsFile */
+ 1024, /* mxPathname */
+ 0, /* pNext */
+ "kvvfs", /* zName */
+ 0, /* pAppData */
+ kvvfsOpen, /* xOpen */
+ kvvfsDelete, /* xDelete */
+ kvvfsAccess, /* xAccess */
+ kvvfsFullPathname, /* xFullPathname */
+ kvvfsDlOpen, /* xDlOpen */
+ 0, /* xDlError */
+ 0, /* xDlSym */
+ 0, /* xDlClose */
+ kvvfsRandomness, /* xRandomness */
+ kvvfsSleep, /* xSleep */
+ kvvfsCurrentTime, /* xCurrentTime */
+ 0, /* xGetLastError */
+ kvvfsCurrentTimeInt64 /* xCurrentTimeInt64 */
+};
+
+/* Methods for sqlite3_file objects referencing a database file
+*/
+static sqlite3_io_methods kvvfs_db_io_methods = {
+ 1, /* iVersion */
+ kvvfsClose, /* xClose */
+ kvvfsReadDb, /* xRead */
+ kvvfsWriteDb, /* xWrite */
+ kvvfsTruncateDb, /* xTruncate */
+ kvvfsSyncDb, /* xSync */
+ kvvfsFileSizeDb, /* xFileSize */
+ kvvfsLock, /* xLock */
+ kvvfsUnlock, /* xUnlock */
+ kvvfsCheckReservedLock, /* xCheckReservedLock */
+ kvvfsFileControlDb, /* xFileControl */
+ kvvfsSectorSize, /* xSectorSize */
+ kvvfsDeviceCharacteristics, /* xDeviceCharacteristics */
+ 0, /* xShmMap */
+ 0, /* xShmLock */
+ 0, /* xShmBarrier */
+ 0, /* xShmUnmap */
+ 0, /* xFetch */
+ 0 /* xUnfetch */
+};
+
+/* Methods for sqlite3_file objects referencing a rollback journal
+*/
+static sqlite3_io_methods kvvfs_jrnl_io_methods = {
+ 1, /* iVersion */
+ kvvfsClose, /* xClose */
+ kvvfsReadJrnl, /* xRead */
+ kvvfsWriteJrnl, /* xWrite */
+ kvvfsTruncateJrnl, /* xTruncate */
+ kvvfsSyncJrnl, /* xSync */
+ kvvfsFileSizeJrnl, /* xFileSize */
+ kvvfsLock, /* xLock */
+ kvvfsUnlock, /* xUnlock */
+ kvvfsCheckReservedLock, /* xCheckReservedLock */
+ kvvfsFileControlJrnl, /* xFileControl */
+ kvvfsSectorSize, /* xSectorSize */
+ kvvfsDeviceCharacteristics, /* xDeviceCharacteristics */
+ 0, /* xShmMap */
+ 0, /* xShmLock */
+ 0, /* xShmBarrier */
+ 0, /* xShmUnmap */
+ 0, /* xFetch */
+ 0 /* xUnfetch */
+};
+
+/****** Storage subsystem **************************************************/
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+/* Forward declarations for the low-level storage engine
+*/
+static int kvstorageWrite(const char*, const char *zKey, const char *zData);
+static int kvstorageDelete(const char*, const char *zKey);
+static int kvstorageRead(const char*, const char *zKey, char *zBuf, int nBuf);
+#define KVSTORAGE_KEY_SZ 32
+
+/* Expand the key name with an appropriate prefix and put the result
+** zKeyOut[]. The zKeyOut[] buffer is assumed to hold at least
+** KVSTORAGE_KEY_SZ bytes.
+*/
+static void kvstorageMakeKey(
+ const char *zClass,
+ const char *zKeyIn,
+ char *zKeyOut
+){
+ sqlite3_snprintf(KVSTORAGE_KEY_SZ, zKeyOut, "kvvfs-%s-%s", zClass, zKeyIn);
+}
+
+/* Write content into a key. zClass is the particular namespace of the
+** underlying key/value store to use - either "local" or "session".
+**
+** Both zKey and zData are zero-terminated pure text strings.
+**
+** Return the number of errors.
+*/
+static int kvstorageWrite(
+ const char *zClass,
+ const char *zKey,
+ const char *zData
+){
+ FILE *fd;
+ char zXKey[KVSTORAGE_KEY_SZ];
+ kvstorageMakeKey(zClass, zKey, zXKey);
+ fd = fopen(zXKey, "wb");
+ if( fd ){
+ SQLITE_KV_TRACE(("KVVFS-WRITE %-15s (%d) %.50s%s\n", zXKey,
+ (int)strlen(zData), zData,
+ strlen(zData)>50 ? "..." : ""));
+ fputs(zData, fd);
+ fclose(fd);
+ return 0;
+ }else{
+ return 1;
+ }
+}
+
+/* Delete a key (with its corresponding data) from the key/value
+** namespace given by zClass. If the key does not previously exist,
+** this routine is a no-op.
+*/
+static int kvstorageDelete(const char *zClass, const char *zKey){
+ char zXKey[KVSTORAGE_KEY_SZ];
+ kvstorageMakeKey(zClass, zKey, zXKey);
+ unlink(zXKey);
+ SQLITE_KV_TRACE(("KVVFS-DELETE %-15s\n", zXKey));
+ return 0;
+}
+
+/* Read the value associated with a zKey from the key/value namespace given
+** by zClass and put the text data associated with that key in the first
+** nBuf bytes of zBuf[]. The value might be truncated if zBuf is not large
+** enough to hold it all. The value put into zBuf must always be zero
+** terminated, even if it gets truncated because nBuf is not large enough.
+**
+** Return the total number of bytes in the data, without truncation, and
+** not counting the final zero terminator. Return -1 if the key does
+** not exist.
+**
+** If nBuf<=0 then this routine simply returns the size of the data without
+** actually reading it.
+*/
+static int kvstorageRead(
+ const char *zClass,
+ const char *zKey,
+ char *zBuf,
+ int nBuf
+){
+ FILE *fd;
+ struct stat buf;
+ char zXKey[KVSTORAGE_KEY_SZ];
+ kvstorageMakeKey(zClass, zKey, zXKey);
+ if( access(zXKey, R_OK)!=0
+ || stat(zXKey, &buf)!=0
+ || !S_ISREG(buf.st_mode)
+ ){
+ SQLITE_KV_TRACE(("KVVFS-READ %-15s (-1)\n", zXKey));
+ return -1;
+ }
+ if( nBuf<=0 ){
+ return (int)buf.st_size;
+ }else if( nBuf==1 ){
+ zBuf[0] = 0;
+ SQLITE_KV_TRACE(("KVVFS-READ %-15s (%d)\n", zXKey,
+ (int)buf.st_size));
+ return (int)buf.st_size;
+ }
+ if( nBuf > buf.st_size + 1 ){
+ nBuf = buf.st_size + 1;
+ }
+ fd = fopen(zXKey, "rb");
+ if( fd==0 ){
+ SQLITE_KV_TRACE(("KVVFS-READ %-15s (-1)\n", zXKey));
+ return -1;
+ }else{
+ sqlite3_int64 n = fread(zBuf, 1, nBuf-1, fd);
+ fclose(fd);
+ zBuf[n] = 0;
+ SQLITE_KV_TRACE(("KVVFS-READ %-15s (%lld) %.50s%s\n", zXKey,
+ n, zBuf, n>50 ? "..." : ""));
+ return (int)n;
+ }
+}
+
+/*
+** An internal level of indirection which enables us to replace the
+** kvvfs i/o methods with JavaScript implementations in WASM builds.
+** Maintenance reminder: if this struct changes in any way, the JSON
+** rendering of its structure must be updated in
+** sqlite3_wasm_enum_json(). There are no binary compatibility
+** concerns, so it does not need an iVersion member. This file is
+** necessarily always compiled together with sqlite3_wasm_enum_json(),
+** and JS code dynamically creates the mapping of members based on
+** that JSON description.
+*/
+typedef struct sqlite3_kvvfs_methods sqlite3_kvvfs_methods;
+struct sqlite3_kvvfs_methods {
+ int (*xRead)(const char *zClass, const char *zKey, char *zBuf, int nBuf);
+ int (*xWrite)(const char *zClass, const char *zKey, const char *zData);
+ int (*xDelete)(const char *zClass, const char *zKey);
+ const int nKeySize;
+};
+
+/*
+** This object holds the kvvfs I/O methods which may be swapped out
+** for JavaScript-side implementations in WASM builds. In such builds
+** it cannot be const, but in native builds it should be so that
+** the compiler can hopefully optimize this level of indirection out.
+** That said, kvvfs is intended primarily for use in WASM builds.
+**
+** Note that this is not explicitly flagged as static because the
+** amalgamation build will tag it with SQLITE_PRIVATE.
+*/
+#ifndef SQLITE_WASM
+const
+#endif
+sqlite3_kvvfs_methods sqlite3KvvfsMethods = {
+kvstorageRead,
+kvstorageWrite,
+kvstorageDelete,
+KVSTORAGE_KEY_SZ
+};
+
+/****** Utility subroutines ************************************************/
+
+/*
+** Encode binary into the text encoded used to persist on disk.
+** The output text is stored in aOut[], which must be at least
+** nData+1 bytes in length.
+**
+** Return the actual length of the encoded text, not counting the
+** zero terminator at the end.
+**
+** Encoding format
+** ---------------
+**
+** * Non-zero bytes are encoded as upper-case hexadecimal
+**
+** * A sequence of one or more zero-bytes that are not at the
+** beginning of the buffer are encoded as a little-endian
+** base-26 number using a..z. "a" means 0. "b" means 1,
+** "z" means 25. "ab" means 26. "ac" means 52. And so forth.
+**
+** * Because there is no overlap between the encoding characters
+** of hexadecimal and base-26 numbers, it is always clear where
+** one stops and the next begins.
+*/
+static int kvvfsEncode(const char *aData, int nData, char *aOut){
+ int i, j;
+ const unsigned char *a = (const unsigned char*)aData;
+ for(i=j=0; i<nData; i++){
+ unsigned char c = a[i];
+ if( c!=0 ){
+ aOut[j++] = "0123456789ABCDEF"[c>>4];
+ aOut[j++] = "0123456789ABCDEF"[c&0xf];
+ }else{
+ /* A sequence of 1 or more zeros is stored as a little-endian
+ ** base-26 number using a..z as the digits. So one zero is "b".
+ ** Two zeros is "c". 25 zeros is "z", 26 zeros is "ab", 27 is "bb",
+ ** and so forth.
+ */
+ int k;
+ for(k=1; i+k<nData && a[i+k]==0; k++){}
+ i += k-1;
+ while( k>0 ){
+ aOut[j++] = 'a'+(k%26);
+ k /= 26;
+ }
+ }
+ }
+ aOut[j] = 0;
+ return j;
+}
+
+static const signed char kvvfsHexValue[256] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+
+/*
+** Decode the text encoding back to binary. The binary content is
+** written into pOut, which must be at least nOut bytes in length.
+**
+** The return value is the number of bytes actually written into aOut[].
+*/
+static int kvvfsDecode(const char *a, char *aOut, int nOut){
+ int i, j;
+ int c;
+ const unsigned char *aIn = (const unsigned char*)a;
+ i = 0;
+ j = 0;
+ while( 1 ){
+ c = kvvfsHexValue[aIn[i]];
+ if( c<0 ){
+ int n = 0;
+ int mult = 1;
+ c = aIn[i];
+ if( c==0 ) break;
+ while( c>='a' && c<='z' ){
+ n += (c - 'a')*mult;
+ mult *= 26;
+ c = aIn[++i];
+ }
+ if( j+n>nOut ) return -1;
+ memset(&aOut[j], 0, n);
+ j += n;
+ if( c==0 || mult==1 ) break; /* progress stalled if mult==1 */
+ }else{
+ aOut[j] = c<<4;
+ c = kvvfsHexValue[aIn[++i]];
+ if( c<0 ) break;
+ aOut[j++] += c;
+ i++;
+ }
+ }
+ return j;
+}
+
+/*
+** Decode a complete journal file. Allocate space in pFile->aJrnl
+** and store the decoding there. Or leave pFile->aJrnl set to NULL
+** if an error is encountered.
+**
+** The first few characters of the text encoding will be a little-endian
+** base-26 number (digits a..z) that is the total number of bytes
+** in the decoded journal file image. This base-26 number is followed
+** by a single space, then the encoding of the journal. The space
+** separator is required to act as a terminator for the base-26 number.
+*/
+static void kvvfsDecodeJournal(
+ KVVfsFile *pFile, /* Store decoding in pFile->aJrnl */
+ const char *zTxt, /* Text encoding. Zero-terminated */
+ int nTxt /* Bytes in zTxt, excluding zero terminator */
+){
+ unsigned int n = 0;
+ int c, i, mult;
+ i = 0;
+ mult = 1;
+ while( (c = zTxt[i++])>='a' && c<='z' ){
+ n += (zTxt[i] - 'a')*mult;
+ mult *= 26;
+ }
+ sqlite3_free(pFile->aJrnl);
+ pFile->aJrnl = sqlite3_malloc64( n );
+ if( pFile->aJrnl==0 ){
+ pFile->nJrnl = 0;
+ return;
+ }
+ pFile->nJrnl = n;
+ n = kvvfsDecode(zTxt+i, pFile->aJrnl, pFile->nJrnl);
+ if( n<pFile->nJrnl ){
+ sqlite3_free(pFile->aJrnl);
+ pFile->aJrnl = 0;
+ pFile->nJrnl = 0;
+ }
+}
+
+/*
+** Read or write the "sz" element, containing the database file size.
+*/
+static sqlite3_int64 kvvfsReadFileSize(KVVfsFile *pFile){
+ char zData[50];
+ zData[0] = 0;
+ sqlite3KvvfsMethods.xRead(pFile->zClass, "sz", zData, sizeof(zData)-1);
+ return strtoll(zData, 0, 0);
+}
+static int kvvfsWriteFileSize(KVVfsFile *pFile, sqlite3_int64 sz){
+ char zData[50];
+ sqlite3_snprintf(sizeof(zData), zData, "%lld", sz);
+ return sqlite3KvvfsMethods.xWrite(pFile->zClass, "sz", zData);
+}
+
+/****** sqlite3_io_methods methods ******************************************/
+
+/*
+** Close an kvvfs-file.
+*/
+static int kvvfsClose(sqlite3_file *pProtoFile){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+
+ SQLITE_KV_LOG(("xClose %s %s\n", pFile->zClass,
+ pFile->isJournal ? "journal" : "db"));
+ sqlite3_free(pFile->aJrnl);
+ sqlite3_free(pFile->aData);
+ return SQLITE_OK;
+}
+
+/*
+** Read from the -journal file.
+*/
+static int kvvfsReadJrnl(
+ sqlite3_file *pProtoFile,
+ void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+ assert( pFile->isJournal );
+ SQLITE_KV_LOG(("xRead('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+ if( pFile->aJrnl==0 ){
+ int szTxt = kvstorageRead(pFile->zClass, "jrnl", 0, 0);
+ char *aTxt;
+ if( szTxt<=4 ){
+ return SQLITE_IOERR;
+ }
+ aTxt = sqlite3_malloc64( szTxt+1 );
+ if( aTxt==0 ) return SQLITE_NOMEM;
+ kvstorageRead(pFile->zClass, "jrnl", aTxt, szTxt+1);
+ kvvfsDecodeJournal(pFile, aTxt, szTxt);
+ sqlite3_free(aTxt);
+ if( pFile->aJrnl==0 ) return SQLITE_IOERR;
+ }
+ if( iOfst+iAmt>pFile->nJrnl ){
+ return SQLITE_IOERR_SHORT_READ;
+ }
+ memcpy(zBuf, pFile->aJrnl+iOfst, iAmt);
+ return SQLITE_OK;
+}
+
+/*
+** Read from the database file.
+*/
+static int kvvfsReadDb(
+ sqlite3_file *pProtoFile,
+ void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+ unsigned int pgno;
+ int got, n;
+ char zKey[30];
+ char *aData = pFile->aData;
+ assert( iOfst>=0 );
+ assert( iAmt>=0 );
+ SQLITE_KV_LOG(("xRead('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+ if( iOfst+iAmt>=512 ){
+ if( (iOfst % iAmt)!=0 ){
+ return SQLITE_IOERR_READ;
+ }
+ if( (iAmt & (iAmt-1))!=0 || iAmt<512 || iAmt>65536 ){
+ return SQLITE_IOERR_READ;
+ }
+ pFile->szPage = iAmt;
+ pgno = 1 + iOfst/iAmt;
+ }else{
+ pgno = 1;
+ }
+ sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+ got = sqlite3KvvfsMethods.xRead(pFile->zClass, zKey,
+ aData, SQLITE_KVOS_SZ-1);
+ if( got<0 ){
+ n = 0;
+ }else{
+ aData[got] = 0;
+ if( iOfst+iAmt<512 ){
+ int k = iOfst+iAmt;
+ aData[k*2] = 0;
+ n = kvvfsDecode(aData, &aData[2000], SQLITE_KVOS_SZ-2000);
+ if( n>=iOfst+iAmt ){
+ memcpy(zBuf, &aData[2000+iOfst], iAmt);
+ n = iAmt;
+ }else{
+ n = 0;
+ }
+ }else{
+ n = kvvfsDecode(aData, zBuf, iAmt);
+ }
+ }
+ if( n<iAmt ){
+ memset(zBuf+n, 0, iAmt-n);
+ return SQLITE_IOERR_SHORT_READ;
+ }
+ return SQLITE_OK;
+}
+
+
+/*
+** Write into the -journal file.
+*/
+static int kvvfsWriteJrnl(
+ sqlite3_file *pProtoFile,
+ const void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+ sqlite3_int64 iEnd = iOfst+iAmt;
+ SQLITE_KV_LOG(("xWrite('%s-journal',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+ if( iEnd>=0x10000000 ) return SQLITE_FULL;
+ if( pFile->aJrnl==0 || pFile->nJrnl<iEnd ){
+ char *aNew = sqlite3_realloc(pFile->aJrnl, iEnd);
+ if( aNew==0 ){
+ return SQLITE_IOERR_NOMEM;
+ }
+ pFile->aJrnl = aNew;
+ if( pFile->nJrnl<iOfst ){
+ memset(pFile->aJrnl+pFile->nJrnl, 0, iOfst-pFile->nJrnl);
+ }
+ pFile->nJrnl = iEnd;
+ }
+ memcpy(pFile->aJrnl+iOfst, zBuf, iAmt);
+ return SQLITE_OK;
+}
+
+/*
+** Write into the database file.
+*/
+static int kvvfsWriteDb(
+ sqlite3_file *pProtoFile,
+ const void *zBuf,
+ int iAmt,
+ sqlite_int64 iOfst
+){
+ KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+ unsigned int pgno;
+ char zKey[30];
+ char *aData = pFile->aData;
+ SQLITE_KV_LOG(("xWrite('%s-db',%d,%lld)\n", pFile->zClass, iAmt, iOfst));
+ assert( iAmt>=512 && iAmt<=65536 );
+ assert( (iAmt & (iAmt-1))==0 );
+ assert( pFile->szPage<0 || pFile->szPage==iAmt );
+ pFile->szPage = iAmt;
+ pgno = 1 + iOfst/iAmt;
+ sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+ kvvfsEncode(zBuf, iAmt, aData);
+ if( sqlite3KvvfsMethods.xWrite(pFile->zClass, zKey, aData) ){
+ return SQLITE_IOERR;
+ }
+ if( iOfst+iAmt > pFile->szDb ){
+ pFile->szDb = iOfst + iAmt;
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Truncate an kvvfs-file.
+*/
+static int kvvfsTruncateJrnl(sqlite3_file *pProtoFile, sqlite_int64 size){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ SQLITE_KV_LOG(("xTruncate('%s-journal',%lld)\n", pFile->zClass, size));
+ assert( size==0 );
+ sqlite3KvvfsMethods.xDelete(pFile->zClass, "jrnl");
+ sqlite3_free(pFile->aJrnl);
+ pFile->aJrnl = 0;
+ pFile->nJrnl = 0;
+ return SQLITE_OK;
+}
+static int kvvfsTruncateDb(sqlite3_file *pProtoFile, sqlite_int64 size){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ if( pFile->szDb>size
+ && pFile->szPage>0
+ && (size % pFile->szPage)==0
+ ){
+ char zKey[50];
+ unsigned int pgno, pgnoMax;
+ SQLITE_KV_LOG(("xTruncate('%s-db',%lld)\n", pFile->zClass, size));
+ pgno = 1 + size/pFile->szPage;
+ pgnoMax = 2 + pFile->szDb/pFile->szPage;
+ while( pgno<=pgnoMax ){
+ sqlite3_snprintf(sizeof(zKey), zKey, "%u", pgno);
+ sqlite3KvvfsMethods.xDelete(pFile->zClass, zKey);
+ pgno++;
+ }
+ pFile->szDb = size;
+ return kvvfsWriteFileSize(pFile, size) ? SQLITE_IOERR : SQLITE_OK;
+ }
+ return SQLITE_IOERR;
+}
+
+/*
+** Sync an kvvfs-file.
+*/
+static int kvvfsSyncJrnl(sqlite3_file *pProtoFile, int flags){
+ int i, n;
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ char *zOut;
+ SQLITE_KV_LOG(("xSync('%s-journal')\n", pFile->zClass));
+ if( pFile->nJrnl<=0 ){
+ return kvvfsTruncateJrnl(pProtoFile, 0);
+ }
+ zOut = sqlite3_malloc64( pFile->nJrnl*2 + 50 );
+ if( zOut==0 ){
+ return SQLITE_IOERR_NOMEM;
+ }
+ n = pFile->nJrnl;
+ i = 0;
+ do{
+ zOut[i++] = 'a' + (n%26);
+ n /= 26;
+ }while( n>0 );
+ zOut[i++] = ' ';
+ kvvfsEncode(pFile->aJrnl, pFile->nJrnl, &zOut[i]);
+ i = sqlite3KvvfsMethods.xWrite(pFile->zClass, "jrnl", zOut);
+ sqlite3_free(zOut);
+ return i ? SQLITE_IOERR : SQLITE_OK;
+}
+static int kvvfsSyncDb(sqlite3_file *pProtoFile, int flags){
+ return SQLITE_OK;
+}
+
+/*
+** Return the current file-size of an kvvfs-file.
+*/
+static int kvvfsFileSizeJrnl(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ SQLITE_KV_LOG(("xFileSize('%s-journal')\n", pFile->zClass));
+ *pSize = pFile->nJrnl;
+ return SQLITE_OK;
+}
+static int kvvfsFileSizeDb(sqlite3_file *pProtoFile, sqlite_int64 *pSize){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ SQLITE_KV_LOG(("xFileSize('%s-db')\n", pFile->zClass));
+ if( pFile->szDb>=0 ){
+ *pSize = pFile->szDb;
+ }else{
+ *pSize = kvvfsReadFileSize(pFile);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Lock an kvvfs-file.
+*/
+static int kvvfsLock(sqlite3_file *pProtoFile, int eLock){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ assert( !pFile->isJournal );
+ SQLITE_KV_LOG(("xLock(%s,%d)\n", pFile->zClass, eLock));
+
+ if( eLock!=SQLITE_LOCK_NONE ){
+ pFile->szDb = kvvfsReadFileSize(pFile);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Unlock an kvvfs-file.
+*/
+static int kvvfsUnlock(sqlite3_file *pProtoFile, int eLock){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ assert( !pFile->isJournal );
+ SQLITE_KV_LOG(("xUnlock(%s,%d)\n", pFile->zClass, eLock));
+ if( eLock==SQLITE_LOCK_NONE ){
+ pFile->szDb = -1;
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an kvvfs-file.
+*/
+static int kvvfsCheckReservedLock(sqlite3_file *pProtoFile, int *pResOut){
+ SQLITE_KV_LOG(("xCheckReservedLock\n"));
+ *pResOut = 0;
+ return SQLITE_OK;
+}
+
+/*
+** File control method. For custom operations on an kvvfs-file.
+*/
+static int kvvfsFileControlJrnl(sqlite3_file *pProtoFile, int op, void *pArg){
+ SQLITE_KV_LOG(("xFileControl(%d) on journal\n", op));
+ return SQLITE_NOTFOUND;
+}
+static int kvvfsFileControlDb(sqlite3_file *pProtoFile, int op, void *pArg){
+ SQLITE_KV_LOG(("xFileControl(%d) on database\n", op));
+ if( op==SQLITE_FCNTL_SYNC ){
+ KVVfsFile *pFile = (KVVfsFile *)pProtoFile;
+ int rc = SQLITE_OK;
+ SQLITE_KV_LOG(("xSync('%s-db')\n", pFile->zClass));
+ if( pFile->szDb>0 && 0!=kvvfsWriteFileSize(pFile, pFile->szDb) ){
+ rc = SQLITE_IOERR;
+ }
+ return rc;
+ }
+ return SQLITE_NOTFOUND;
+}
+
+/*
+** Return the sector-size in bytes for an kvvfs-file.
+*/
+static int kvvfsSectorSize(sqlite3_file *pFile){
+ return 512;
+}
+
+/*
+** Return the device characteristic flags supported by an kvvfs-file.
+*/
+static int kvvfsDeviceCharacteristics(sqlite3_file *pProtoFile){
+ return 0;
+}
+
+/****** sqlite3_vfs methods *************************************************/
+
+/*
+** Open an kvvfs file handle.
+*/
+static int kvvfsOpen(
+ sqlite3_vfs *pProtoVfs,
+ const char *zName,
+ sqlite3_file *pProtoFile,
+ int flags,
+ int *pOutFlags
+){
+ KVVfsFile *pFile = (KVVfsFile*)pProtoFile;
+ if( zName==0 ) zName = "";
+ SQLITE_KV_LOG(("xOpen(\"%s\")\n", zName));
+ if( strcmp(zName, "local")==0
+ || strcmp(zName, "session")==0
+ ){
+ pFile->isJournal = 0;
+ pFile->base.pMethods = &kvvfs_db_io_methods;
+ }else
+ if( strcmp(zName, "local-journal")==0
+ || strcmp(zName, "session-journal")==0
+ ){
+ pFile->isJournal = 1;
+ pFile->base.pMethods = &kvvfs_jrnl_io_methods;
+ }else{
+ return SQLITE_CANTOPEN;
+ }
+ if( zName[0]=='s' ){
+ pFile->zClass = "session";
+ }else{
+ pFile->zClass = "local";
+ }
+ pFile->aData = sqlite3_malloc64(SQLITE_KVOS_SZ);
+ if( pFile->aData==0 ){
+ return SQLITE_NOMEM;
+ }
+ pFile->aJrnl = 0;
+ pFile->nJrnl = 0;
+ pFile->szPage = -1;
+ pFile->szDb = -1;
+ return SQLITE_OK;
+}
+
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int kvvfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+ if( strcmp(zPath, "local-journal")==0 ){
+ sqlite3KvvfsMethods.xDelete("local", "jrnl");
+ }else
+ if( strcmp(zPath, "session-journal")==0 ){
+ sqlite3KvvfsMethods.xDelete("session", "jrnl");
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int kvvfsAccess(
+ sqlite3_vfs *pProtoVfs,
+ const char *zPath,
+ int flags,
+ int *pResOut
+){
+ SQLITE_KV_LOG(("xAccess(\"%s\")\n", zPath));
+ if( strcmp(zPath, "local-journal")==0 ){
+ *pResOut = sqlite3KvvfsMethods.xRead("local", "jrnl", 0, 0)>0;
+ }else
+ if( strcmp(zPath, "session-journal")==0 ){
+ *pResOut = sqlite3KvvfsMethods.xRead("session", "jrnl", 0, 0)>0;
+ }else
+ if( strcmp(zPath, "local")==0 ){
+ *pResOut = sqlite3KvvfsMethods.xRead("local", "sz", 0, 0)>0;
+ }else
+ if( strcmp(zPath, "session")==0 ){
+ *pResOut = sqlite3KvvfsMethods.xRead("session", "sz", 0, 0)>0;
+ }else
+ {
+ *pResOut = 0;
+ }
+ SQLITE_KV_LOG(("xAccess returns %d\n",*pResOut));
+ return SQLITE_OK;
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int kvvfsFullPathname(
+ sqlite3_vfs *pVfs,
+ const char *zPath,
+ int nOut,
+ char *zOut
+){
+ size_t nPath;
+#ifdef SQLITE_OS_KV_ALWAYS_LOCAL
+ zPath = "local";
+#endif
+ nPath = strlen(zPath);
+ SQLITE_KV_LOG(("xFullPathname(\"%s\")\n", zPath));
+ if( nOut<nPath+1 ) nPath = nOut - 1;
+ memcpy(zOut, zPath, nPath);
+ zOut[nPath] = 0;
+ return SQLITE_OK;
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *kvvfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+ return 0;
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of
+** random data.
+*/
+static int kvvfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+ memset(zBufOut, 0, nByte);
+ return nByte;
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds
+** actually slept.
+*/
+static int kvvfsSleep(sqlite3_vfs *pVfs, int nMicro){
+ return SQLITE_OK;
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int kvvfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+ sqlite3_int64 i = 0;
+ int rc;
+ rc = kvvfsCurrentTimeInt64(0, &i);
+ *pTimeOut = i/86400000.0;
+ return rc;
+}
+#include <sys/time.h>
+static int kvvfsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
+ static const sqlite3_int64 unixEpoch = 24405875*(sqlite3_int64)8640000;
+ struct timeval sNow;
+ (void)gettimeofday(&sNow, 0); /* Cannot fail given valid arguments */
+ *pTimeOut = unixEpoch + 1000*(sqlite3_int64)sNow.tv_sec + sNow.tv_usec/1000;
+ return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV || SQLITE_OS_UNIX */
+
+#if SQLITE_OS_KV
+/*
+** This routine is called initialize the KV-vfs as the default VFS.
+*/
+int sqlite3_os_init(void){
+ return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 1);
+}
+int sqlite3_os_end(void){
+ return SQLITE_OK;
+}
+#endif /* SQLITE_OS_KV */
+
+#if SQLITE_OS_UNIX && defined(SQLITE_OS_KV_OPTIONAL)
+int sqlite3KvvfsInit(void){
+ return sqlite3_vfs_register(&sqlite3OsKvvfsObject, 0);
+}
+#endif