[PATCH 0/2] Remove one use of struct buffer

[PATCH 0/2] Remove one use of struct buffer

[Simon Marchi]

Tom mentioned the goal of getting rid of struct buffer, and that made me
remember I had these patches laying around.

Simon Marchi (2):
  gdbsupport: add string_xml_appendf
  gdb: convert linux-osdata.c from buffer to std::string

 gdb/nat/linux-osdata.c  | 287 +++++++++++++++++++++-------------------
 gdbsupport/xml-utils.cc | 105 +++++++++++++++
 gdbsupport/xml-utils.h  |  10 ++
 3 files changed, 263 insertions(+), 139 deletions(-)


base-commit: de75275fe54c5536c8238f0f3f88bb7ac2222942
-- 
2.38.1

[PATCH 1/2] gdbsupport: add string_xml_appendf

[Simon Marchi]

Add a version of buffer_xml_printf (defined in gdbsupport/buffer.{c,h})
that appends to an std::string, rather than a struct buffer.  Call it
"string" rather than "buffer" since it operates on an std::string rather
than a buffer.  And call it "appendf" rather than "printf", since it
appends to and does not replace the string's content.  This mirrors
string_appendf.

Place the new version in gdbsupport/xml-utils.h.

The code is a direct copy of buffer_xml_printf.  The old version is
going to disappear at some point, which is why I didn't do any effort to
share code.

Change-Id: I30e030627ab4970fd0b9eba3b7e8cec78fa561ba
---
 gdbsupport/xml-utils.cc | 105 ++++++++++++++++++++++++++++++++++++++++
 gdbsupport/xml-utils.h  |  10 ++++
 2 files changed, 115 insertions(+)

diff --git a/gdbsupport/xml-utils.cc b/gdbsupport/xml-utils.cc
index e47e23ced590..c74bcdd1155d 100644
--- a/gdbsupport/xml-utils.cc
+++ b/gdbsupport/xml-utils.cc
@@ -61,3 +61,108 @@ xml_escape_text_append (std::string &result, const char *text)
 	break;
       }
 }
+
+/* See xml-utils.h.  */
+
+void
+string_xml_appendf (std::string &buffer, const char *format, ...)
+{
+  va_list ap;
+  const char *f;
+  const char *prev;
+  int percent = 0;
+
+  va_start (ap, format);
+
+  prev = format;
+  for (f = format; *f; f++)
+    {
+      if (percent)
+	{
+	  char buf[32];
+	  char *str = buf;
+	  const char *f_old = f;
+
+	  switch (*f)
+	    {
+	    case 's':
+	      str = va_arg (ap, char *);
+	      break;
+	    case 'd':
+	      sprintf (str, "%d", va_arg (ap, int));
+	      break;
+	    case 'u':
+	      sprintf (str, "%u", va_arg (ap, unsigned int));
+	      break;
+	    case 'x':
+	      sprintf (str, "%x", va_arg (ap, unsigned int));
+	      break;
+	    case 'o':
+	      sprintf (str, "%o", va_arg (ap, unsigned int));
+	      break;
+	    case 'l':
+	      f++;
+	      switch (*f)
+		{
+		case 'd':
+		  sprintf (str, "%ld", va_arg (ap, long));
+		  break;
+		case 'u':
+		  sprintf (str, "%lu", va_arg (ap, unsigned long));
+		  break;
+		case 'x':
+		  sprintf (str, "%lx", va_arg (ap, unsigned long));
+		  break;
+		case 'o':
+		  sprintf (str, "%lo", va_arg (ap, unsigned long));
+		  break;
+		case 'l':
+		  f++;
+		  switch (*f)
+		    {
+		    case 'd':
+		      sprintf (str, "%" PRId64,
+			       (int64_t) va_arg (ap, long long));
+		      break;
+		    case 'u':
+		      sprintf (str, "%" PRIu64,
+			       (uint64_t) va_arg (ap, unsigned long long));
+		      break;
+		    case 'x':
+		      sprintf (str, "%" PRIx64,
+			       (uint64_t) va_arg (ap, unsigned long long));
+		      break;
+		    case 'o':
+		      sprintf (str, "%" PRIo64,
+			       (uint64_t) va_arg (ap, unsigned long long));
+		      break;
+		    default:
+		      str = 0;
+		      break;
+		    }
+		  break;
+		default:
+		  str = 0;
+		  break;
+		}
+	      break;
+	    default:
+	      str = 0;
+	      break;
+	    }
+
+	  if (str)
+	    {
+	      buffer.append (prev, f_old - prev - 1);
+	      xml_escape_text_append (buffer, str);
+	      prev = f + 1;
+	    }
+	  percent = 0;
+	}
+      else if (*f == '%')
+	percent = 1;
+    }
+
+  buffer.append (prev);
+  va_end (ap);
+}
diff --git a/gdbsupport/xml-utils.h b/gdbsupport/xml-utils.h
index 695263c5b379..09714027030f 100644
--- a/gdbsupport/xml-utils.h
+++ b/gdbsupport/xml-utils.h
@@ -30,4 +30,14 @@ extern std::string xml_escape_text (const char *text);
 
 extern void xml_escape_text_append (std::string &result, const char *text);
 
+/* Simple printf to string function.  Current implemented formatters:
+   %s - append an xml escaped text to BUFFER.
+   %d - append an signed integer to BUFFER.
+   %u - append an unsigned integer to BUFFER.
+   %x - append an unsigned integer formatted in hexadecimal to BUFFER.
+   %o - append an unsigned integer formatted in octal to BUFFER.  */
+
+void string_xml_appendf (std::string &buffer, const char *format, ...)
+  ATTRIBUTE_PRINTF (2, 3);
+
 #endif /* COMMON_XML_UTILS_H */
-- 
2.38.1

[PATCH 2/2] gdb: convert linux-osdata.c from buffer to std::string

[Simon Marchi]

Replace the use of struct buffer in linux-osdata.c with std::string.
There is not change in the logic, so there should be no user-visible
change.

Change-Id: I27f53165d401650bbd0bebe8ed88221e25545b3f
---
 gdb/nat/linux-osdata.c | 287 +++++++++++++++++++++--------------------
 1 file changed, 148 insertions(+), 139 deletions(-)

diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index 8639f090910a..73a052560264 100644
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -333,12 +333,11 @@ get_core_array_size ()
   return sysconf (_SC_NPROCESSORS_ONLN);
 }
 
-static void
-linux_xfer_osdata_processes (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_processes ()
 {
   DIR *dirp;
-
-  buffer_grow_str (buffer, "<osdata type=\"processes\">\n");
+  std::string buffer = "<osdata type=\"processes\">\n";
 
   dirp = opendir ("/proc");
   if (dirp)
@@ -385,7 +384,7 @@ linux_xfer_osdata_processes (struct buffer *buffer)
 
 	  xfree (cores);
 
-	  buffer_xml_printf
+	  string_xml_appendf
 	    (buffer,
 	     "<item>"
 	     "<column name=\"pid\">%lld</column>"
@@ -404,7 +403,9 @@ linux_xfer_osdata_processes (struct buffer *buffer)
       closedir (dirp);
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* A simple PID/PGID pair.  */
@@ -446,12 +447,11 @@ struct pid_pgid_entry
 
 /* Collect all process groups from /proc in BUFFER.  */
 
-static void
-linux_xfer_osdata_processgroups (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_processgroups ()
 {
   DIR *dirp;
-
-  buffer_grow_str (buffer, "<osdata type=\"process groups\">\n");
+  std::string buffer = "<osdata type=\"process groups\">\n";
 
   dirp = opendir ("/proc");
   if (dirp)
@@ -493,7 +493,7 @@ linux_xfer_osdata_processgroups (struct buffer *buffer)
 	  command_from_pid (leader_command, sizeof (leader_command), pgid);
 	  command_line = commandline_from_pid (pid);
 
-	  buffer_xml_printf
+	  string_xml_appendf
 	    (buffer,
 	     "<item>"
 	     "<column name=\"pgid\">%lld</column>"
@@ -510,18 +510,19 @@ linux_xfer_osdata_processgroups (struct buffer *buffer)
 	}
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect all the threads in /proc by iterating through processes and
-   then tasks within each process in BUFFER.  */
+   then tasks within each process.  */
 
-static void
-linux_xfer_osdata_threads (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_threads ()
 {
   DIR *dirp;
-
-  buffer_grow_str (buffer, "<osdata type=\"threads\">\n");
+  std::string buffer = "<osdata type=\"threads\">\n";
 
   dirp = opendir ("/proc");
   if (dirp)
@@ -570,7 +571,7 @@ linux_xfer_osdata_threads (struct buffer *buffer)
 		      tid = atoi (dp2->d_name);
 		      core = linux_common_core_of_thread (ptid_t (pid, tid));
 
-		      buffer_xml_printf
+		      string_xml_appendf
 			(buffer,
 			 "<item>"
 			 "<column name=\"pid\">%lld</column>"
@@ -592,17 +593,18 @@ linux_xfer_osdata_threads (struct buffer *buffer)
       closedir (dirp);
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect data about the cpus/cores on the system in BUFFER.  */
 
-static void
-linux_xfer_osdata_cpus (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_cpus ()
 {
   int first_item = 1;
-
-  buffer_grow_str (buffer, "<osdata type=\"cpus\">\n");
+  std::string buffer = "<osdata type=\"cpus\">\n";
 
   gdb_file_up fp = gdb_fopen_cloexec ("/proc/cpuinfo", "r");
   if (fp != NULL)
@@ -639,37 +641,38 @@ linux_xfer_osdata_cpus (struct buffer *buffer)
 	      if (strcmp (key, "processor") == 0)
 		{
 		  if (first_item)
-		    buffer_grow_str (buffer, "<item>");
+		    buffer += "<item>";
 		  else
-		    buffer_grow_str (buffer, "</item><item>");
+		    buffer += "</item><item>";
 
 		  first_item = 0;
 		}
 
-	      buffer_xml_printf (buffer,
-				 "<column name=\"%s\">%s</column>",
-				 key,
-				 value);
+	      string_xml_appendf (buffer,
+				  "<column name=\"%s\">%s</column>",
+				  key,
+				  value);
 	    }
 	}
       while (!feof (fp.get ()));
 
       if (first_item == 0)
-	buffer_grow_str (buffer, "</item>");
+	buffer += "</item>";
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect all the open file descriptors found in /proc and put the details
    found about them into BUFFER.  */
 
-static void
-linux_xfer_osdata_fds (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_fds ()
 {
   DIR *dirp;
-
-  buffer_grow_str (buffer, "<osdata type=\"files\">\n");
+  std::string buffer = "<osdata type=\"files\">\n";
 
   dirp = opendir ("/proc");
   if (dirp)
@@ -721,7 +724,7 @@ linux_xfer_osdata_fds (struct buffer *buffer)
 		      if (rslt >= 0)
 			buf[rslt] = '\0';
 
-		      buffer_xml_printf
+		      string_xml_appendf
 			(buffer,
 			 "<item>"
 			 "<column name=\"pid\">%s</column>"
@@ -743,7 +746,9 @@ linux_xfer_osdata_fds (struct buffer *buffer)
       closedir (dirp);
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Returns the socket state STATE in textual form.  */
@@ -808,7 +813,7 @@ union socket_addr
    otherwise only UDP sockets are processed.  */
 
 static void
-print_sockets (unsigned short family, int tcp, struct buffer *buffer)
+print_sockets (unsigned short family, int tcp, std::string &buffer)
 {
   const char *proc_file;
 
@@ -909,26 +914,26 @@ print_sockets (unsigned short family, int tcp, struct buffer *buffer)
 
 		  user_from_uid (user, sizeof (user), uid);
 
-		  buffer_xml_printf (
-		      buffer,
-		      "<item>"
-		      "<column name=\"local address\">%s</column>"
-		      "<column name=\"local port\">%s</column>"
-		      "<column name=\"remote address\">%s</column>"
-		      "<column name=\"remote port\">%s</column>"
-		      "<column name=\"state\">%s</column>"
-		      "<column name=\"user\">%s</column>"
-		      "<column name=\"family\">%s</column>"
-		      "<column name=\"protocol\">%s</column>"
-		      "</item>",
-		      local_address,
-		      local_service,
-		      remote_address,
-		      remote_service,
-		      format_socket_state (state),
-		      user,
-		      (family == AF_INET) ? "INET" : "INET6",
-		      tcp ? "STREAM" : "DGRAM");
+		  string_xml_appendf
+		    (buffer,
+		     "<item>"
+		     "<column name=\"local address\">%s</column>"
+		     "<column name=\"local port\">%s</column>"
+		     "<column name=\"remote address\">%s</column>"
+		     "<column name=\"remote port\">%s</column>"
+		     "<column name=\"state\">%s</column>"
+		     "<column name=\"user\">%s</column>"
+		     "<column name=\"family\">%s</column>"
+		     "<column name=\"protocol\">%s</column>"
+		     "</item>",
+		     local_address,
+		     local_service,
+		     remote_address,
+		     remote_service,
+		     format_socket_state (state),
+		     user,
+		     (family == AF_INET) ? "INET" : "INET6",
+		     tcp ? "STREAM" : "DGRAM");
 		}
 	    }
 	}
@@ -938,17 +943,19 @@ print_sockets (unsigned short family, int tcp, struct buffer *buffer)
 
 /* Collect data about internet sockets and write it into BUFFER.  */
 
-static void
-linux_xfer_osdata_isockets (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_isockets ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"I sockets\">\n");
+  std::string buffer = "<osdata type=\"I sockets\">\n";
 
   print_sockets (AF_INET, 1, buffer);
   print_sockets (AF_INET, 0, buffer);
   print_sockets (AF_INET6, 1, buffer);
   print_sockets (AF_INET6, 0, buffer);
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Converts the time SECONDS into textual form and copies it into a
@@ -993,10 +1000,10 @@ group_from_gid (char *group, int maxlen, gid_t gid)
 /* Collect data about shared memory recorded in /proc and write it
    into BUFFER.  */
 
-static void
-linux_xfer_osdata_shm (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_shm ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"shared memory\">\n");
+  std::string buffer = "<osdata type=\"shared memory\">\n";
 
   gdb_file_up fp = gdb_fopen_cloexec ("/proc/sysvipc/shm", "r");
   if (fp)
@@ -1043,7 +1050,7 @@ linux_xfer_osdata_shm (struct buffer *buffer)
 		  time_from_time_t (dtime_str, sizeof (dtime_str), dtime);
 		  time_from_time_t (ctime_str, sizeof (ctime_str), ctime);
 
-		  buffer_xml_printf
+		  string_xml_appendf
 		    (buffer,
 		     "<item>"
 		     "<column name=\"key\">%d</column>"
@@ -1081,16 +1088,18 @@ linux_xfer_osdata_shm (struct buffer *buffer)
       while (!feof (fp.get ()));
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect data about semaphores recorded in /proc and write it
    into BUFFER.  */
 
-static void
-linux_xfer_osdata_sem (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_sem ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"semaphores\">\n");
+  std::string buffer = "<osdata type=\"semaphores\">\n";
 
   gdb_file_up fp = gdb_fopen_cloexec ("/proc/sysvipc/sem", "r");
   if (fp)
@@ -1129,7 +1138,7 @@ linux_xfer_osdata_sem (struct buffer *buffer)
 		  time_from_time_t (otime_str, sizeof (otime_str), otime);
 		  time_from_time_t (ctime_str, sizeof (ctime_str), ctime);
 
-		  buffer_xml_printf
+		  string_xml_appendf
 		    (buffer,
 		     "<item>"
 		     "<column name=\"key\">%d</column>"
@@ -1159,16 +1168,18 @@ linux_xfer_osdata_sem (struct buffer *buffer)
       while (!feof (fp.get ()));
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect data about message queues recorded in /proc and write it
    into BUFFER.  */
 
-static void
-linux_xfer_osdata_msg (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_msg ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"message queues\">\n");
+  std::string buffer = "<osdata type=\"message queues\">\n";
 
   gdb_file_up fp = gdb_fopen_cloexec ("/proc/sysvipc/msg", "r");
   if (fp)
@@ -1213,7 +1224,7 @@ linux_xfer_osdata_msg (struct buffer *buffer)
 		  time_from_time_t (rtime_str, sizeof (rtime_str), rtime);
 		  time_from_time_t (ctime_str, sizeof (ctime_str), ctime);
 
-		  buffer_xml_printf
+		  string_xml_appendf
 		    (buffer,
 		     "<item>"
 		     "<column name=\"key\">%d</column>"
@@ -1251,16 +1262,18 @@ linux_xfer_osdata_msg (struct buffer *buffer)
       while (!feof (fp.get ()));
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 /* Collect data about loaded kernel modules and write it into
    BUFFER.  */
 
-static void
-linux_xfer_osdata_modules (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_modules ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"modules\">\n");
+  std::string buffer = "<osdata type=\"modules\">\n";
 
   gdb_file_up fp = gdb_fopen_cloexec ("/proc/modules", "r");
   if (fp)
@@ -1306,84 +1319,87 @@ linux_xfer_osdata_modules (struct buffer *buffer)
 	      if (sscanf (tmp, "%llx", &address) != 1)
 		continue;
 
-	      buffer_xml_printf (buffer,
-				 "<item>"
-				 "<column name=\"name\">%s</column>"
-				 "<column name=\"size\">%u</column>"
-				 "<column name=\"num uses\">%d</column>"
-				 "<column name=\"dependencies\">%s</column>"
-				 "<column name=\"status\">%s</column>"
-				 "<column name=\"address\">%llx</column>"
-				 "</item>",
-				 name,
-				 size,
-				 uses,
-				 dependencies,
-				 status,
-				 address);
+	      string_xml_appendf (buffer,
+				  "<item>"
+				  "<column name=\"name\">%s</column>"
+				  "<column name=\"size\">%u</column>"
+				  "<column name=\"num uses\">%d</column>"
+				  "<column name=\"dependencies\">%s</column>"
+				  "<column name=\"status\">%s</column>"
+				  "<column name=\"address\">%llx</column>"
+				  "</item>",
+				  name,
+				  size,
+				  uses,
+				  dependencies,
+				  status,
+				  address);
 	    }
 	}
       while (!feof (fp.get ()));
     }
 
-  buffer_grow_str0 (buffer, "</osdata>\n");
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
-static void linux_xfer_osdata_info_os_types (struct buffer *buffer);
+static std::string linux_xfer_osdata_info_os_types ();
 
 static struct osdata_type {
   const char *type;
   const char *title;
   const char *description;
-  void (*take_snapshot) (struct buffer *buffer);
-  LONGEST len_avail;
-  struct buffer buffer;
+  std::string (*take_snapshot) ();
+  std::string buffer;
 } osdata_table[] = {
   { "types", "Types", "Listing of info os types you can list",
-    linux_xfer_osdata_info_os_types, -1 },
+    linux_xfer_osdata_info_os_types },
   { "cpus", "CPUs", "Listing of all cpus/cores on the system",
-    linux_xfer_osdata_cpus, -1 },
+    linux_xfer_osdata_cpus },
   { "files", "File descriptors", "Listing of all file descriptors",
-    linux_xfer_osdata_fds, -1 },
+    linux_xfer_osdata_fds },
   { "modules", "Kernel modules", "Listing of all loaded kernel modules",
-    linux_xfer_osdata_modules, -1 },
+    linux_xfer_osdata_modules },
   { "msg", "Message queues", "Listing of all message queues",
-    linux_xfer_osdata_msg, -1 },
+    linux_xfer_osdata_msg },
   { "processes", "Processes", "Listing of all processes",
-    linux_xfer_osdata_processes, -1 },
+    linux_xfer_osdata_processes },
   { "procgroups", "Process groups", "Listing of all process groups",
-    linux_xfer_osdata_processgroups, -1 },
+    linux_xfer_osdata_processgroups },
   { "semaphores", "Semaphores", "Listing of all semaphores",
-    linux_xfer_osdata_sem, -1 },
+    linux_xfer_osdata_sem },
   { "shm", "Shared-memory regions", "Listing of all shared-memory regions",
-    linux_xfer_osdata_shm, -1 },
+    linux_xfer_osdata_shm },
   { "sockets", "Sockets", "Listing of all internet-domain sockets",
-    linux_xfer_osdata_isockets, -1 },
+    linux_xfer_osdata_isockets },
   { "threads", "Threads", "Listing of all threads",
-  linux_xfer_osdata_threads, -1 },
+    linux_xfer_osdata_threads },
   { NULL, NULL, NULL }
 };
 
 /* Collect data about all types info os can show in BUFFER.  */
 
-static void
-linux_xfer_osdata_info_os_types (struct buffer *buffer)
+static std::string
+linux_xfer_osdata_info_os_types ()
 {
-  buffer_grow_str (buffer, "<osdata type=\"types\">\n");
+  std::string buffer = "<osdata type=\"types\">\n";
 
   /* Start the below loop at 1, as we do not want to list ourselves.  */
   for (int i = 1; osdata_table[i].type; ++i)
-    buffer_xml_printf (buffer,
-		       "<item>"
-		       "<column name=\"Type\">%s</column>"
-		       "<column name=\"Description\">%s</column>"
-		       "<column name=\"Title\">%s</column>"
-		       "</item>",
-		       osdata_table[i].type,
-		       osdata_table[i].description,
-		       osdata_table[i].title);
-
-  buffer_grow_str0 (buffer, "</osdata>\n");
+    string_xml_appendf (buffer,
+			"<item>"
+			"<column name=\"Type\">%s</column>"
+			"<column name=\"Description\">%s</column>"
+			"<column name=\"Title\">%s</column>"
+			"</item>",
+			osdata_table[i].type,
+			osdata_table[i].description,
+			osdata_table[i].title);
+
+  buffer += "</osdata>\n";
+
+  return buffer;
 }
 
 
@@ -1397,24 +1413,17 @@ common_getter (struct osdata_type *osd,
   gdb_assert (readbuf);
 
   if (offset == 0)
-    {
-      if (osd->len_avail != -1 && osd->len_avail != 0)
-	buffer_free (&osd->buffer);
-      osd->len_avail = 0;
-      buffer_init (&osd->buffer);
-      (osd->take_snapshot) (&osd->buffer);
-      osd->len_avail = strlen (osd->buffer.buffer);
-    }
-  if (offset >= osd->len_avail)
+    osd->buffer = osd->take_snapshot ();
+
+  if (offset >= osd->buffer.size ())
     {
       /* Done.  Get rid of the buffer.  */
-      buffer_free (&osd->buffer);
-      osd->len_avail = 0;
+      osd->buffer.clear ();
       return 0;
     }
-  if (len > osd->len_avail - offset)
-    len = osd->len_avail - offset;
-  memcpy (readbuf, osd->buffer.buffer + offset, len);
+
+  len = std::min (len, osd->buffer.size () - offset);
+  memcpy (readbuf, &osd->buffer[offset], len);
 
   return len;
 
-- 
2.38.1

Re: [PATCH 0/2] Remove one use of struct buffer

[Pedro Alves]

On 2022-12-16 6:01 a.m., Simon Marchi via Gdb-patches wrote:
> Tom mentioned the goal of getting rid of struct buffer, and that made me
> remember I had these patches laying around.
> 

Yeah, IIRC, struct buffer existed avoid obstack in gdbserver I think because
back then gdbserver didn't link with libiberty.  There used to be a obstack_xml_printf
function too, which was eliminated too since.  Glad to see it all go.

> Simon Marchi (2):
>   gdbsupport: add string_xml_appendf
>   gdb: convert linux-osdata.c from buffer to std::string

LGTM.

("There is not change" -> "There is no change" in patch 2's commit log.)

> 
>  gdb/nat/linux-osdata.c  | 287 +++++++++++++++++++++-------------------
>  gdbsupport/xml-utils.cc | 105 +++++++++++++++
>  gdbsupport/xml-utils.h  |  10 ++
>  3 files changed, 263 insertions(+), 139 deletions(-)
> 
> 
> base-commit: de75275fe54c5536c8238f0f3f88bb7ac2222942
> 

Re: [PATCH 0/2] Remove one use of struct buffer

[Simon Marchi]

On 12/16/22 08:09, Pedro Alves wrote:
> On 2022-12-16 6:01 a.m., Simon Marchi via Gdb-patches wrote:
>> Tom mentioned the goal of getting rid of struct buffer, and that made me
>> remember I had these patches laying around.
>>
> 
> Yeah, IIRC, struct buffer existed avoid obstack in gdbserver I think because
> back then gdbserver didn't link with libiberty.  There used to be a obstack_xml_printf
> function too, which was eliminated too since.  Glad to see it all go.
> 
>> Simon Marchi (2):
>>   gdbsupport: add string_xml_appendf
>>   gdb: convert linux-osdata.c from buffer to std::string
> 
> LGTM.
> 
> ("There is not change" -> "There is no change" in patch 2's commit log.)

Fixed and pushed, thanks.

Simon

Re: [PATCH 0/2] Remove one use of struct buffer

[Tom Tromey]

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> Tom mentioned the goal of getting rid of struct buffer, and that made me
Simon> remember I had these patches laying around.

Thanks for doing this.  I have patches to remove all the uses of struct
buffer except the one in event-top.c.  I plan to write that one a bit
later though.

Tom