1 files changed, 496 insertions, 0 deletions
diff --git a/sql/my_json_writer.cc b/sql/my_json_writer.cc
new file mode 100644
index 00000000..54eb8423
--- /dev/null
+++ b/sql/my_json_writer.cc
@@ -0,0 +1,496 @@
+/* Copyright (C) 2014, 2021, MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+#include "my_global.h"
+#include "my_json_writer.h"
+
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+
+bool Json_writer::named_item_expected() const
+{
+  return named_items_expectation.size()
+      && named_items_expectation.back();
+}
+#endif
+
+void Json_writer::append_indent()
+{
+  if (!document_start)
+    output.append('\n');
+  for (int i=0; i< indent_level; i++)
+    output.append(' ');
+}
+
+inline void Json_writer::on_start_object()
+{
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  if(!fmt_helper.is_making_writer_calls())
+  {
+    if (got_name != named_item_expected())
+    {
+      sql_print_error(got_name
+                      ? "Json_writer got a member name which is not expected.\n"
+                      : "Json_writer: a member name was expected.\n");
+      VALIDITY_ASSERT(got_name == named_item_expected());
+    }
+    named_items_expectation.push_back(true);
+  }
+#endif
+  fmt_helper.on_start_object();
+}
+
+void Json_writer::start_object()
+{
+  on_start_object();
+
+  if (!element_started)
+    start_element();
+
+  output.append('{');
+  indent_level+=INDENT_SIZE;
+  first_child=true;
+  element_started= false;
+  document_start= false;
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  got_name= false;
+  named_items.emplace();
+#endif
+}
+
+void Json_writer::start_array()
+{
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  if(!fmt_helper.is_making_writer_calls())
+  {
+    VALIDITY_ASSERT(got_name == named_item_expected());
+    named_items_expectation.push_back(false);
+    got_name= false;
+    if (document_start)
+      named_items.emplace();
+  }
+#endif
+
+  if (fmt_helper.on_start_array())
+    return;
+
+  if (!element_started)
+    start_element();
+
+  output.append('[');
+  indent_level+=INDENT_SIZE;
+  first_child=true;
+  element_started= false;
+  document_start= false;
+}
+
+
+void Json_writer::end_object()
+{
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  VALIDITY_ASSERT(named_item_expected());
+  named_items_expectation.pop_back();
+  VALIDITY_ASSERT(!got_name);
+  got_name= false;
+  VALIDITY_ASSERT(named_items.size());
+  named_items.pop();
+#endif
+  indent_level-=INDENT_SIZE;
+  if (!first_child)
+    append_indent();
+  first_child= false;
+  output.append('}');
+}
+
+
+void Json_writer::end_array()
+{
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  VALIDITY_ASSERT(!named_item_expected());
+  named_items_expectation.pop_back();
+  got_name= false;
+#endif
+  if (fmt_helper.on_end_array())
+    return;
+  indent_level-=INDENT_SIZE;
+  if (!first_child)
+    append_indent();
+  output.append(']');
+}
+
+
+Json_writer& Json_writer::add_member(const char *name)
+{
+  size_t len= strlen(name);
+  return add_member(name, len);
+}
+
+Json_writer& Json_writer::add_member(const char *name, size_t len)
+{
+  if (!fmt_helper.on_add_member(name, len))
+  {
+    // assert that we are in an object
+    DBUG_ASSERT(!element_started);
+    start_element();
+
+    output.append('"');
+    output.append(name, len);
+    output.append(STRING_WITH_LEN("\": "));
+  }
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  if (!fmt_helper.is_making_writer_calls())
+  {
+    VALIDITY_ASSERT(!got_name);
+    got_name= true;
+    VALIDITY_ASSERT(named_items.size());
+    auto& named_items_keys= named_items.top();
+    auto emplaced= named_items_keys.emplace(name, len);
+    auto is_uniq_key= emplaced.second;
+    if(!is_uniq_key)
+    {
+      sql_print_error("Duplicated key: %s\n", emplaced.first->c_str());
+      VALIDITY_ASSERT(is_uniq_key);
+    }
+  }
+#endif
+  return *this;
+}
+
+
+/* 
+  Used by formatting helper to print something that is formatted by the helper.
+  We should only separate it from the previous element.
+*/
+
+void Json_writer::start_sub_element()
+{
+  //element_started= true;
+  if (first_child)
+    first_child= false;
+  else
+    output.append(',');
+
+  append_indent();
+}
+
+
+void Json_writer::start_element()
+{
+  element_started= true;
+
+  if (first_child)
+    first_child= false;
+  else
+    output.append(',');
+
+  append_indent();
+}
+
+void Json_writer::add_ll(longlong val)
+{
+  char buf[64];
+  my_snprintf(buf, sizeof(buf), "%lld", val);
+  add_unquoted_str(buf);
+}
+
+void Json_writer::add_ull(ulonglong val)
+{
+  char buf[64];
+  my_snprintf(buf, sizeof(buf), "%llu", val);
+  add_unquoted_str(buf);
+}
+
+
+/* Add a memory size, printing in Kb, Kb, Gb if necessary */
+void Json_writer::add_size(longlong val)
+{
+  char buf[64];
+  size_t len;
+  if (val < 1024) 
+    len= my_snprintf(buf, sizeof(buf), "%lld", val);
+  else if (val < 1024*1024*16)
+  {
+    /* Values less than 16MB are specified in KB for precision */
+    len= my_snprintf(buf, sizeof(buf), "%lld", val/1024);
+    strcpy(buf + len, "Kb");
+    len+= 2;
+  }
+  else
+  {
+    len= my_snprintf(buf, sizeof(buf), "%lld", val/(1024*1024));
+    strcpy(buf + len, "Mb");
+    len+= 2;
+  }
+  add_str(buf, len);
+}
+
+
+void Json_writer::add_double(double val)
+{
+  char buf[64];
+  size_t len= my_snprintf(buf, sizeof(buf), "%-.11lg", val);
+  add_unquoted_str(buf, len);
+}
+
+
+void Json_writer::add_bool(bool val)
+{
+  add_unquoted_str(val? "true" : "false");
+}
+
+
+void Json_writer::add_null()
+{
+  add_unquoted_str("null", (size_t) 4);
+}
+
+
+void Json_writer::add_unquoted_str(const char* str)
+{
+  size_t len= strlen(str);
+  add_unquoted_str(str, len);
+}
+
+void Json_writer::add_unquoted_str(const char* str, size_t len)
+{
+  VALIDITY_ASSERT(fmt_helper.is_making_writer_calls() ||
+                  got_name == named_item_expected());
+  if (on_add_str(str, len))
+    return;
+
+  if (!element_started)
+    start_element();
+
+  output.append(str, len);
+  element_started= false;
+}
+
+inline bool Json_writer::on_add_str(const char *str, size_t num_bytes)
+{
+#if !defined(NDEBUG) || defined(JSON_WRITER_UNIT_TEST)
+  got_name= false;
+#endif
+  bool helped= fmt_helper.on_add_str(str, num_bytes);
+  return helped;
+}
+
+void Json_writer::add_str(const char *str)
+{
+  size_t len= strlen(str);
+  add_str(str, len);
+}
+
+/*
+  This function is used to add only num_bytes of str to the output string
+*/
+
+void Json_writer::add_str(const char* str, size_t num_bytes)
+{
+  VALIDITY_ASSERT(fmt_helper.is_making_writer_calls() ||
+                  got_name == named_item_expected());
+  if (on_add_str(str, num_bytes))
+    return;
+
+  if (!element_started)
+    start_element();
+
+  output.append('"');
+  output.append(str, num_bytes);
+  output.append('"');
+  element_started= false;
+}
+
+void Json_writer::add_str(const String &str)
+{
+  add_str(str.ptr(), str.length());
+}
+
+#ifdef ENABLED_JSON_WRITER_CONSISTENCY_CHECKS
+thread_local std::vector<bool> Json_writer_struct::named_items_expectation;
+#endif
+
+Json_writer_temp_disable::Json_writer_temp_disable(THD *thd_arg)
+{
+  thd= thd_arg;
+  thd->opt_trace.disable_tracing_if_required();
+}
+Json_writer_temp_disable::~Json_writer_temp_disable()
+{
+  thd->opt_trace.enable_tracing_if_required();
+}
+
+bool Single_line_formatting_helper::on_add_member(const char *name,
+                                                  size_t len)
+{
+  DBUG_ASSERT(state== INACTIVE || state == DISABLED);
+  if (state != DISABLED)
+  {
+    // remove everything from the array
+    buf_ptr= buffer;
+
+    //append member name to the array
+    if (len < MAX_LINE_LEN)
+    {
+      memcpy(buf_ptr, name, len);
+      buf_ptr+=len;
+      *(buf_ptr++)= 0;
+
+      line_len= owner->indent_level + (uint)len + 1;
+      state= ADD_MEMBER;
+      return true; // handled
+    }
+  }
+  return false; // not handled
+}
+
+
+bool Single_line_formatting_helper::on_start_array()
+{
+  if (state == ADD_MEMBER)
+  {
+    state= IN_ARRAY;
+    return true; // handled
+  }
+  else
+  {
+    if (state != DISABLED)
+      state= INACTIVE;
+    // TODO: what if we have accumulated some stuff already? shouldn't we
+    // flush it?
+    return false; // not handled
+  }
+}
+
+
+bool Single_line_formatting_helper::on_end_array()
+{
+  if (state == IN_ARRAY)
+  {
+    flush_on_one_line();
+    state= INACTIVE;
+    return true; // handled
+  }
+  return false; // not handled
+}
+
+
+void Single_line_formatting_helper::on_start_object()
+{
+  // Nested objects will not be printed on one line
+  disable_and_flush();
+}
+
+
+bool Single_line_formatting_helper::on_add_str(const char *str,
+                                               size_t len)
+{
+  if (state == IN_ARRAY)
+  {
+    // New length will be:
+    //  "$string", 
+    //  quote + quote + comma + space = 4
+    if (line_len + len + 4 > MAX_LINE_LEN)
+    {
+      disable_and_flush();
+      return false; // didn't handle the last element
+    }
+
+    //append string to array
+    memcpy(buf_ptr, str, len);
+    buf_ptr+=len;
+    *(buf_ptr++)= 0;
+    line_len += (uint)len + 4;
+    return true; // handled
+  }
+
+  disable_and_flush();
+  return false; // not handled
+}
+
+
+/*
+  Append everything accumulated to the output on one line
+*/
+
+void Single_line_formatting_helper::flush_on_one_line()
+{
+  owner->start_sub_element();
+  char *ptr= buffer;
+  int nr= 0;
+  while (ptr < buf_ptr)
+  {
+    char *str= ptr;
+
+    if (nr == 0)
+    {
+      owner->output.append('"');
+      owner->output.append(str);
+      owner->output.append(STRING_WITH_LEN("\": "));
+      owner->output.append('[');
+    }
+    else
+    {
+      if (nr != 1)
+        owner->output.append(STRING_WITH_LEN(", "));
+      owner->output.append('"');
+      owner->output.append(str);
+      owner->output.append('"');
+    }
+    nr++;
+
+    while (*ptr!=0)
+      ptr++;
+    ptr++;
+  }
+  owner->output.append(']');
+  /* We've printed out the contents of the buffer, mark it as empty */
+  buf_ptr= buffer;
+}
+
+
+void Single_line_formatting_helper::disable_and_flush()
+{
+  if (state == DISABLED)
+    return;
+
+  bool start_array= (state == IN_ARRAY);
+  state= DISABLED;
+  // deactivate ourselves and flush all accumulated calls.
+  char *ptr= buffer;
+  int nr= 0;
+  while (ptr < buf_ptr)
+  {
+    char *str= ptr;
+    size_t len= strlen(str);
+
+    if (nr == 0)
+    {
+      owner->add_member(str, len);
+      if (start_array)
+        owner->start_array();
+    }
+    else
+    {
+      //if (nr == 1)
+      //  owner->start_array();
+      owner->add_str(str, len);
+    }
+    
+    nr++;
+    ptr+= len+1;
+  }
+  buf_ptr= buffer;
+  state= INACTIVE;
+}
+