From 3a67b0453e359e3f9158f51682eb07125ec1d4db Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Mon, 18 Aug 2014 17:56:31 +0000
Subject: Add the "changeset" command-line utility for getting an ASCII dump of
 change sets.

FossilOrigin-Name: 55bb3544a6b474c04853270067a35ca4b0079f52
---
 ext/session/changeset.c | 314 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 314 insertions(+)
 create mode 100644 ext/session/changeset.c

(limited to 'ext/session/changeset.c')

diff --git a/ext/session/changeset.c b/ext/session/changeset.c
new file mode 100644
index 000000000..62817a64e
--- /dev/null
+++ b/ext/session/changeset.c
@@ -0,0 +1,314 @@
+/*
+** 2014-08-18
+**
+** 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 code to implement the "changeset" command line
+** utility for displaying and transforming changesets generated by
+** the Sessions extension.
+*/
+#include "sqlite3.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+
+
+/*
+** Show a usage message on stderr then quit.
+*/
+static void usage(const char *argv0){
+  fprintf(stderr, "Usage: %s FILENAME COMMAND ...\n", argv0);
+  fprintf(stderr,
+    "COMMANDs:\n"
+    "   apply DB           Apply the changeset to database file DB\n"
+    "   concat FILE2 OUT   Concatenate FILENAME and FILE2 into OUT\n"
+    "   dump               Show the complete content of the changeset\n"
+    "   invert OUT         Write an inverted changeset into file OUT\n"
+    "   sql                Give a pseudo-SQL rendering of the changeset\n"
+  );
+  exit(1);
+}
+
+/*
+** Read the content of a disk file into an in-memory buffer
+*/
+static void readFile(const char *zFilename, int *pSz, void **ppBuf){
+  FILE *f;
+  int sz;
+  void *pBuf;
+  f = fopen(zFilename, "rb");
+  if( f==0 ){
+    fprintf(stderr, "cannot open \"%s\" for reading\n", zFilename);
+    exit(1);
+  }
+  fseek(f, 0, SEEK_END);
+  sz = (int)ftell(f);
+  rewind(f);
+  pBuf = sqlite3_malloc( sz ? sz : 1 );
+  if( pBuf==0 ){
+    fprintf(stderr, "cannot allocate %d to hold content of \"%s\"\n",
+            sz, zFilename);
+    exit(1);
+  }
+  if( sz>0 ){
+    if( fread(pBuf, sz, 1, f)!=1 ){
+      fprintf(stderr, "cannot read all %d bytes of \"%s\"\n", sz, zFilename);
+      exit(1);
+    }
+    fclose(f);
+  }
+  *pSz = sz;
+  *ppBuf = pBuf;
+}
+
+/* Array for converting from half-bytes (nybbles) into ASCII hex
+** digits. */
+static const char hexdigits[] = {
+  '0', '1', '2', '3', '4', '5', '6', '7',
+  '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' 
+};
+
+/*
+** Render an sqlite3_value as an SQL string.
+*/
+static void renderValue(sqlite3_value *pVal){
+  switch( sqlite3_value_type(pVal) ){
+    case SQLITE_FLOAT: {
+      double r1;
+      char zBuf[50];
+      r1 = sqlite3_value_double(pVal);
+      sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
+      printf("%s", zBuf);
+      break;
+    }
+    case SQLITE_INTEGER: {
+      printf("%lld", sqlite3_value_int64(pVal));
+      break;
+    }
+    case SQLITE_BLOB: {
+      char const *zBlob = sqlite3_value_blob(pVal);
+      int nBlob = sqlite3_value_bytes(pVal);
+      int i;
+      printf("x'");
+      for(i=0; i<nBlob; i++){
+        putchar(hexdigits[(zBlob[i]>>4)&0x0F]);
+        putchar(hexdigits[(zBlob[i])&0x0F]);
+      }
+      putchar('\'');
+      break;
+    }
+    case SQLITE_TEXT: {
+      const unsigned char *zArg = sqlite3_value_text(pVal);
+      putchar('\'');
+      while( zArg[0] ){
+        putchar(zArg[0]);
+        if( zArg[0]=='\'' ) putchar(zArg[0]);
+        zArg++;
+      }
+      putchar('\'');
+      break;
+    }
+    default: {
+      assert( sqlite3_value_type(pVal)==SQLITE_NULL );
+      printf("NULL");
+      break;
+    }
+  }
+}
+
+int main(int argc, char **argv){
+  int sz, rc;
+  void *pBuf = 0;
+  if( argc<3 ) usage(argv[0]);
+  readFile(argv[1], &sz, &pBuf);
+
+  /* changeset FILENAME apply DB
+  ** Apply the changeset in FILENAME to the database file DB
+  */
+  if( strcmp(argv[2],"apply")==0 ){
+    fprintf(stderr, "not yet implemented\n");
+  }else
+
+  /* changeset FILENAME concat FILE2 OUT
+  ** Add changeset FILE2 onto the end of the changeset in FILENAME
+  ** and write the result into OUT.
+  */
+  if( strcmp(argv[2],"concat")==0 ){
+    fprintf(stderr, "not yet implemented\n");
+  }else
+
+  /* changeset FILENAME dump
+  ** Show the complete content of the changeset in FILENAME
+  */
+  if( strcmp(argv[2],"dump")==0 ){
+    int cnt = 0;
+    int i;
+    sqlite3_changeset_iter *pIter;
+    rc = sqlite3changeset_start(&pIter, sz, pBuf);
+    if( rc!=SQLITE_OK ){
+      fprintf(stderr, "sqlite3changeset_start() returns %d\n", rc);
+      exit(1);
+    }
+    while( sqlite3changeset_next(pIter)==SQLITE_ROW ){
+      int op, bIndirect, nCol;
+      const char *zTab;
+      unsigned char *abPK;
+      sqlite3changeset_op(pIter, &zTab, &nCol, &op, &bIndirect);
+      cnt++;
+      printf("%d: %s table=[%s] indirect=%d nColumn=%d\n",
+             cnt, op==SQLITE_INSERT ? "INSERT" :
+                       op==SQLITE_UPDATE ? "UPDATE" : "DELETE",
+             zTab, bIndirect, nCol);
+      sqlite3changeset_pk(pIter, &abPK, 0);
+      for(i=0; i<nCol; i++){
+        sqlite3_value *pVal;
+        pVal = 0;
+        sqlite3changeset_old(pIter, i, &pVal);
+        if( pVal ){
+          printf("    old[%d]%s = ", i, abPK[i] ? "pk" : "  ");
+          renderValue(pVal);
+          printf("\n");
+        }
+        pVal = 0;
+        sqlite3changeset_new(pIter, i, &pVal);
+        if( pVal ){
+          printf("    new[%d]%s = ", i, abPK[i] ? "pk" : "  ");
+          renderValue(pVal);
+          printf("\n");
+        }
+      }
+    }
+    sqlite3changeset_finalize(pIter);
+  }else
+
+  /* changeset FILENAME invert OUT
+  ** Invert the changes in FILENAME and writes the result on OUT
+  */
+  if( strcmp(argv[2],"invert")==0 ){
+    FILE *out;
+    int szOut = 0;
+    void *pOutBuf = 0;
+    if( argc!=4 ) usage(argv[0]);
+    out = fopen(argv[3], "wb");
+    if( out==0 ){
+      fprintf(stderr, "cannot open \"%s\" for writing\n", argv[3]);
+      exit(1);
+    }
+    sqlite3changeset_invert(sz, pBuf, &szOut, &pOutBuf);
+    if( fwrite(pOutBuf, szOut, 1, out)!=1 ){
+      fprintf(stderr, "unable to write all %d bytes of output to \"%s\"\n",
+              szOut, argv[3]);
+    }
+    fclose(out);
+    sqlite3_free(pOutBuf);
+  }else
+
+  /* changeset FILE sql
+  ** Show the content of the changeset as pseudo-SQL
+  */
+  if( strcmp(argv[2],"sql")==0 ){
+    int cnt = 0;
+    char *zPrevTab = 0;
+    char *zSQLTabName = 0;
+    sqlite3_changeset_iter *pIter = 0;
+    rc = sqlite3changeset_start(&pIter, sz, pBuf);
+    if( rc!=SQLITE_OK ){
+      fprintf(stderr, "sqlite3changeset_start() returns %d\n", rc);
+      exit(1);
+    }
+    printf("BEGIN;\n");
+    while( sqlite3changeset_next(pIter)==SQLITE_ROW ){
+      int op, bIndirect, nCol;
+      const char *zTab;
+      sqlite3changeset_op(pIter, &zTab, &nCol, &op, &bIndirect);
+      cnt++;
+      if( zPrevTab==0 || strcmp(zPrevTab,zTab)!=0 ){
+        sqlite3_free(zPrevTab);
+        sqlite3_free(zSQLTabName);
+        zPrevTab = sqlite3_mprintf("%s", zTab);
+        if( !isalnum(zTab[0]) || sqlite3_strglob("*[^a-zA-Z0-9]*",zTab)==0 ){
+          zSQLTabName = sqlite3_mprintf("\"%w\"", zTab);
+        }else{
+          zSQLTabName = sqlite3_mprintf("%s", zTab);
+        }
+        printf("/****** Changes for table %s ***************/\n", zSQLTabName);
+      }
+      switch( op ){
+        case SQLITE_DELETE: {
+          unsigned char *abPK;
+          int i;
+          const char *zSep = " ";
+          sqlite3changeset_pk(pIter, &abPK, 0);
+          printf("/* %d */ DELETE FROM %s WHERE", cnt, zSQLTabName);
+          for(i=0; i<nCol; i++){
+            sqlite3_value *pVal;
+            if( abPK[i]==0 ) continue;
+            printf("%sc%d=", zSep, i+1);
+            zSep = " AND ";
+            sqlite3changeset_old(pIter, i, &pVal);
+            renderValue(pVal);
+          }
+          printf(";\n");
+          break;
+        }
+        case SQLITE_UPDATE: {
+          unsigned char *abPK;
+          int i;
+          const char *zSep = " ";
+          sqlite3changeset_pk(pIter, &abPK, 0);
+          printf("/* %d */ UPDATE %s SET", cnt, zSQLTabName);
+          for(i=0; i<nCol; i++){
+            sqlite3_value *pVal = 0;
+            sqlite3changeset_new(pIter, i, &pVal);
+            if( pVal ){
+              printf("%sc%d=", zSep, i+1);
+              zSep = ", ";
+              renderValue(pVal);
+            }
+          }
+          printf(" WHERE");
+          zSep = " ";
+          for(i=0; i<nCol; i++){
+            sqlite3_value *pVal;
+            if( abPK[i]==0 ) continue;
+            printf("%sc%d=", zSep, i+1);
+            zSep = " AND ";
+            sqlite3changeset_old(pIter, i, &pVal);
+            renderValue(pVal);
+          }
+          printf(";\n");
+          break;
+        }
+        case SQLITE_INSERT: {
+          int i;
+          printf("/* %d */ INSERT INTO %s VALUES", cnt, zSQLTabName);
+          for(i=0; i<nCol; i++){
+            sqlite3_value *pVal;
+            printf("%c", i==0 ? '(' : ',');
+            sqlite3changeset_new(pIter, i, &pVal);
+            renderValue(pVal);
+          }
+          printf(");\n");
+          break;
+        }
+      }
+    }
+    printf("COMMIT;\n");
+    sqlite3changeset_finalize(pIter);
+    sqlite3_free(zPrevTab);
+    sqlite3_free(zSQLTabName);
+  }else
+
+  /* If nothing else matches, show the usage comment */
+  usage(argv[0]);
+  sqlite3_free(pBuf);
+  return 0; 
+}
-- 
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