*/
static void fts5WriteBtreeTerm(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegWriter *pWriter,         /* Writer object */
  int nTerm, const u8 *pTerm      /* First term on new page */
){
  fts5WriteFlushBtree(p, pWriter);

  fts5BufferSet(&p->rc, &pWriter->btterm, nTerm, pTerm);
  pWriter->iBtPage = pWriter->writer.pgno;

}

/*
** This function is called when flushing a leaf page that contains no
** terms at all to disk.
*/
static void fts5WriteBtreeNoTerm(
................................................................................
  assert( pPage->buf.n>=4 );
  assert( pPage->buf.n>4 || pWriter->bFirstTermInPage );

  /* If the current leaf page is full, flush it to disk. */
  if( (pPage->buf.n + pPgidx->n + nTerm + 2)>=p->pConfig->pgsz ){
    if( pPage->buf.n>4 ){
      fts5WriteFlushLeaf(p, pWriter);

    }
    fts5BufferGrow(&p->rc, &pPage->buf, nTerm+FTS5_DATA_PADDING);
  }
  
  /* TODO1: Updating pgidx here. */
  pPgidx->n += sqlite3Fts5PutVarint(
      &pPgidx->p[pPgidx->n], pPage->buf.n - pPage->iPrevPgidx
................................................................................
      ** copy of (pTerm/nTerm) into the parent node. This is slightly
      ** inefficient, but still correct.  */
      int n = nTerm;
      if( pPage->term.n ){
        n = 1 + fts5PrefixCompress(nMin, pPage->term.p, pTerm);
      }
      fts5WriteBtreeTerm(p, pWriter, n, pTerm);

      pPage = &pWriter->writer;
    }
  }else{
    nPrefix = fts5PrefixCompress(nMin, pPage->term.p, pTerm);
    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPrefix);
  }

................................................................................
      const char *zTerm;          /* Buffer containing term */
      const u8 *pDoclist;         /* Pointer to doclist for this term */
      int nDoclist;               /* Size of doclist in bytes */

      /* Write the term for this entry to disk. */
      sqlite3Fts5HashScanEntry(pHash, &zTerm, &pDoclist, &nDoclist);
      fts5WriteAppendTerm(p, &writer, (int)strlen(zTerm), (const u8*)zTerm);


      assert( writer.bFirstRowidInPage==0 );
      if( pgsz>=(pBuf->n + pPgidx->n + nDoclist + 1) ){
        /* The entire doclist will fit on the current leaf. */
        fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
      }else{
        i64 iRowid = 0;
................................................................................
          }
        }
      }

      /* TODO2: Doclist terminator written here. */
      /* pBuf->p[pBuf->n++] = '\0'; */
      assert( pBuf->n<=pBuf->nSpace );
      sqlite3Fts5HashScanNext(pHash);
    }
    sqlite3Fts5HashClear(pHash);
    fts5WriteFinish(p, &writer, &pgnoLast);

    /* Update the Fts5Structure. It is written back to the database by the
    ** fts5StructureRelease() call below.  */
    if( pStruct->nLevel==0 ){

*/
static void fts5WriteBtreeTerm(
  Fts5Index *p,                   /* FTS5 backend object */
  Fts5SegWriter *pWriter,         /* Writer object */
  int nTerm, const u8 *pTerm      /* First term on new page */
){
  fts5WriteFlushBtree(p, pWriter);
  if( p->rc==SQLITE_OK ){
    fts5BufferSet(&p->rc, &pWriter->btterm, nTerm, pTerm);
    pWriter->iBtPage = pWriter->writer.pgno;
  }
}

/*
** This function is called when flushing a leaf page that contains no
** terms at all to disk.
*/
static void fts5WriteBtreeNoTerm(
................................................................................
  assert( pPage->buf.n>=4 );
  assert( pPage->buf.n>4 || pWriter->bFirstTermInPage );

  /* If the current leaf page is full, flush it to disk. */
  if( (pPage->buf.n + pPgidx->n + nTerm + 2)>=p->pConfig->pgsz ){
    if( pPage->buf.n>4 ){
      fts5WriteFlushLeaf(p, pWriter);
      if( p->rc!=SQLITE_OK ) return;
    }
    fts5BufferGrow(&p->rc, &pPage->buf, nTerm+FTS5_DATA_PADDING);
  }
  
  /* TODO1: Updating pgidx here. */
  pPgidx->n += sqlite3Fts5PutVarint(
      &pPgidx->p[pPgidx->n], pPage->buf.n - pPage->iPrevPgidx
................................................................................
      ** copy of (pTerm/nTerm) into the parent node. This is slightly
      ** inefficient, but still correct.  */
      int n = nTerm;
      if( pPage->term.n ){
        n = 1 + fts5PrefixCompress(nMin, pPage->term.p, pTerm);
      }
      fts5WriteBtreeTerm(p, pWriter, n, pTerm);
      if( p->rc!=SQLITE_OK ) return;
      pPage = &pWriter->writer;
    }
  }else{
    nPrefix = fts5PrefixCompress(nMin, pPage->term.p, pTerm);
    fts5BufferAppendVarint(&p->rc, &pPage->buf, nPrefix);
  }

................................................................................
      const char *zTerm;          /* Buffer containing term */
      const u8 *pDoclist;         /* Pointer to doclist for this term */
      int nDoclist;               /* Size of doclist in bytes */

      /* Write the term for this entry to disk. */
      sqlite3Fts5HashScanEntry(pHash, &zTerm, &pDoclist, &nDoclist);
      fts5WriteAppendTerm(p, &writer, (int)strlen(zTerm), (const u8*)zTerm);
      if( p->rc!=SQLITE_OK ) break;

      assert( writer.bFirstRowidInPage==0 );
      if( pgsz>=(pBuf->n + pPgidx->n + nDoclist + 1) ){
        /* The entire doclist will fit on the current leaf. */
        fts5BufferSafeAppendBlob(pBuf, pDoclist, nDoclist);
      }else{
        i64 iRowid = 0;
................................................................................
          }
        }
      }

      /* TODO2: Doclist terminator written here. */
      /* pBuf->p[pBuf->n++] = '\0'; */
      assert( pBuf->n<=pBuf->nSpace );
      if( p->rc==SQLITE_OK ) sqlite3Fts5HashScanNext(pHash);
    }
    sqlite3Fts5HashClear(pHash);
    fts5WriteFinish(p, &writer, &pgnoLast);

    /* Update the Fts5Structure. It is written back to the database by the
    ** fts5StructureRelease() call below.  */
    if( pStruct->nLevel==0 ){

# 2019 Jan 4
#
# 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 implements regression tests for SQLite library.  The
# focus of this script is testing the FTS5 module.
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5interrupt

# If SQLITE_ENABLE_FTS5 is not defined, omit this file.
ifcapable !fts5 {
  finish_test
  return
}

do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(a);
  INSERT INTO t1(t1, rank) VALUES('pgsz', 40);
}
db_save_and_close

proc progress_handler {args} {
  incr ::progress_handler_delay -1
  if {$::progress_handler_delay<=0} { return 1 } 
  return 0
}

foreach {tn sql} {
  1 { INSERT INTO t1(rowid, a) VALUES(0, 'z z z z') }
  2 { COMMIT }
} {
  set bDone 0
  for {set i 1} {$bDone==0} {incr i} {
    do_test 1.$tn.$i {
      db_restore_and_reopen
      execsql {
        BEGIN;
          INSERT INTO t1(rowid, a) VALUES(1, 'a b c d');
          INSERT INTO t1(rowid, a) VALUES(2, 'd e f g');
          INSERT INTO t1(rowid, a) VALUES(3, 'h i j k');
          INSERT INTO t1(rowid, a) VALUES(4, 'l m n o');
      }
  
      set ::progress_handler_delay $i
      db progress 1 progress_handler
      set res [catchsql $sql]
      db close
      if {$res=="0 {}"} {
        set bDone 1
      } else {
        if {$res!="1 interrupted"} { error "got: $res" }
      }
      set {} {}
    } {}
  }
}

finish_test