From: drh <>
Date: Thu, 9 Apr 2026 23:37:48 +0000 (+0000)
Subject: A prototype of code that shows how to expand backslash escapes in the
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=850104bbad3627b868b2588de0d7a99a4ee6c487;p=thirdparty%2Fsqlite.git

A prototype of code that shows how to expand backslash escapes in the
CLI prompt.

FossilOrigin-Name: 9cf28959671920b4909521bb1db6f0cbbc85448fbf3594c43b4000505b4e055b
---

diff --git a/manifest b/manifest
index 8ad58a623b..997b4f4cf1 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Store\sthe\sprompts\sas\spart\sof\sthe\sShellState\sobject,\snot\sas\sglobal\svariables.
-D 2026-04-09T22:14:58.383
+C A\sprototype\sof\scode\sthat\sshows\show\sto\sexpand\sbackslash\sescapes\sin\sthe\nCLI\sprompt.
+D 2026-04-09T23:37:48.087
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -735,7 +735,7 @@ F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c 928ff887f2a7c64275182060d94d06fdddbe32226c569781cf7e7edc6f58d7fd
 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97
 F src/select.c ffe199f025a0dd74670d2a77232bdea364a4d7b36f32c64a6572d39ba6a11576
-F src/shell.c.in 41b2b8ed58a2b34ca1b3027ab73fa5f21fa5a359025ec4d803fff43e5053c85e
+F src/shell.c.in 35f99690f368ef171713cbccd89efef382944e4b85396bdb78e6995636e278b3
 F src/sqlite.h.in e2915e4a86d5e0783afb5cb72411df38d987c7f3c5aa2d5441b8e74d30b649d8
 F src/sqlite3.rc 015537e6ac1eec6c7050e17b616c2ffe6f70fca241835a84a4f0d5937383c479
 F src/sqlite3ext.h 1b7a0ee438bb5c2896d0609c537e917d8057b3340f6ad004d2de44f03e3d3cca
@@ -2197,8 +2197,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P ab08b7a8ef518f96a549a41fe8ff11776abe5e83153c5f8d5d58694ecc476389
-R 94a7119792f4c428d79e21c5509da5f9
+P 39f6c5a8a7d91e03f89b13496e333b9500977a2cbcc0c27ba14dfb87dc81e678
+R d2a4bc02232fb4db2f52e0b9d98461ba
 U drh
-Z 849f1289eaea61587540a79ea11d0c87
+Z f5b6fe9da177b5e89ebf6c4cb7c9f5ea
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index e245a501de..3544fb98a0 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-39f6c5a8a7d91e03f89b13496e333b9500977a2cbcc0c27ba14dfb87dc81e678
+9cf28959671920b4909521bb1db6f0cbbc85448fbf3594c43b4000505b4e055b
diff --git a/src/shell.c.in b/src/shell.c.in
index fa2c9d829b..88956da841 100644
--- a/src/shell.c.in
+++ b/src/shell.c.in
@@ -926,12 +926,101 @@ static char *local_getline(char *zLine, FILE *in){
   return zLine;
 }
 
+/*
+** Expand escapes in the given input prompt string.  Return the
+** expanded prompt in memory obtained from sqlite3_malloc().  The
+** caller is responsible for freeing the memory.
+*/
+static char *expand_prompt(
+  ShellState *p,        /* The current shell state */
+  const char *zPrior,   /* Prior input lines not yet processed */
+  const char *zPrompt   /* Prompt string to be expanded */
+){
+  sqlite3_str *pOut = sqlite3_str_new(0);
+  int i;
+  char c;
+  for(i=0; zPrompt[i]; i++){
+    if( zPrompt[i]!='\\' ) continue;
+    if( i>0 ){
+      sqlite3_str_append(pOut, zPrompt, i);
+      zPrompt += i;
+      i = 0;
+    }
+    /* At this point zPrompt[0] is a \ character and all prior
+    ** characters have already been loaded into pOut.  Process the
+    ** escape sequence that zPrompt points to. */
+    c = zPrompt[1];
+    if( c==0 ){
+      /* \ at the end of a line is silently ignored */
+      break;
+    }
+    if( c=='\\' ){
+      /* \\ maps into a single \  */
+      zPrompt++;
+      continue;
+    }
+    if( c>='0' && c<='7' ){
+      /* \nnn becomes a single byte given by octal nnn */
+      int v = c - '0';
+      while( i<=2 && zPrompt[i+1]>='0' && zPrompt[i+1]<='7' ){
+        v = v*8 + zPrompt[++i] - '0';
+      }
+      sqlite3_str_appendchar(pOut, 1, v);
+      zPrompt += i+1;
+      i = -1;
+      continue;
+    }
+    if( c=='x' ){
+      /* \x becomes "*" if in a transaction and nothing if not */
+      if( p->db && !sqlite3_get_autocommit(p->db) ){
+        sqlite3_str_append(pOut, "*", 1);
+      }
+      zPrompt += 2;
+      i = -1;
+      continue;
+    }
+    if( c=='f' || c=='F' || c=='~' ){
+      /* \f becomes the tail of the database filename */
+      /* \F becomes the full pathname */
+      /* \~ becomes the full pathname relative to $HOME */
+      sqlite3_filename pFN = p->db ? sqlite3_db_filename(p->db,0) : 0;
+      const char *zFN;
+      if( pFN && (zFN = sqlite3_filename_database(pFN))!=0 ){
+        if( c=='f' ){
+          const char *zTail = strrchr(zFN,'/');
+          if( zTail && zTail[1] ) zFN = &zTail[1];
+        }else if( c=='~' ){
+          const char *zHOME = getenv("HOME");
+          size_t nHOME = zHOME ? strlen(zHOME) : 0;
+          if( nHOME<strlen(zFN) && memcmp(zHOME,zFN,nHOME)==0 ){
+            sqlite3_str_append(pOut,"~",1);
+            zFN += nHOME;
+          }
+        }
+        sqlite3_str_appendall(pOut, zFN);
+      }
+      zPrompt += 2;
+      i = -1;
+      continue;
+    }
+
+    /* No match to a known escape.  Generate an error. */
+    sqlite3_str_appendf(pOut,"UNKNOWN(\"\\%c\")",c);
+    zPrompt += 2;
+    i = -1;
+  }
+  if( i>0 ){
+    sqlite3_str_append(pOut, zPrompt, i);
+  }
+  return sqlite3_str_finish(pOut);
+}
+
 /*
 ** Retrieve a single line of input text.
 **
 ** If in==0 then read from standard input and prompt before each line.
-** If isContinuation is true, then a continuation prompt is appropriate.
-** If isContinuation is zero, then the main prompt should be used.
+** If bContinue is true, then a continuation prompt is appropriate.
+** If bContinue is zero, then the main prompt should be used.
 **
 ** If zPrior is not NULL then it is a buffer from a prior call to this
 ** routine that can be reused.
@@ -941,14 +1030,15 @@ static char *local_getline(char *zLine, FILE *in){
 ** zPrior argument for reuse.
 */
 #ifndef SQLITE_SHELL_FIDDLE
-static char *one_input_line(ShellState *p, char *zPrior, int isContinuation){
-  char *zPrompt;
+static char *one_input_line(ShellState *p, char *zPrior, int bContinue){
   char *zResult;
   FILE *in = p->in;
   if( in!=0 ){
     zResult = local_getline(zPrior, in);
   }else{
-    zPrompt = isContinuation ? p->contPrompt : p->mainPrompt;
+    const char *zBase = bContinue ? p->contPrompt : p->mainPrompt;
+    char *zPrompt = expand_prompt(p, zPrior, zBase);
+    shell_check_oom(zPrompt);
 #if SHELL_USE_LOCAL_GETLINE
     sputz(stdout, zPrompt);
     fflush(stdout);
@@ -969,6 +1059,7 @@ static char *one_input_line(ShellState *p, char *zPrior, int isContinuation){
     }
     if( zResult && *zResult ) shell_add_history(zResult);
 #endif
+    sqlite3_free(zPrompt);
   }
   return zResult;
 }
@@ -12202,7 +12293,7 @@ static void echo_group_input(ShellState *p, const char *zDo){
 ** impl because we need the global shellState and cannot access it from that
 ** function without moving lots of code around (creating a larger/messier diff).
 */
-static char *one_input_line(ShellState *p, char *zPrior, int isContinuation){
+static char *one_input_line(ShellState *p, char *zPrior, int bContinue){
   /* Parse the next line from shellState.wasm.zInput. */
   const char *zBegin = shellState.wasm.zPos;
   const char *z = zBegin;
@@ -12211,7 +12302,7 @@ static char *one_input_line(ShellState *p, char *zPrior, int isContinuation){
   FILE *in = p->in;
 
   UNUSED_PARAMETER(in);
-  UNUSED_PARAMETER(isContinuation);
+  UNUSED_PARAMETER(bContinue);
   if(!z || !*z){
     return 0;
   }