html/082persist.cc.html


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<span class="Comment">//: Dead simple persistence.</span>
<span class="Comment">//:   'restore' - reads string from a file</span>
<span class="Comment">//:   'save' - writes string to a file</span>

<span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
RESTORE<span class="Delimiter">,</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;restore&quot;</span><span class="Delimiter">,</span> RESTORE<span class="Delimiter">);</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
case RESTORE: <span class="Delimiter">{</span>
  if <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">)</span> != <span class="Constant">1</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    raise_error &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'restore' requires exactly one ingredient, but got &quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>to_string<span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  string filename<span class="Delimiter">;</span>
  if <span class="Delimiter">(</span>is_literal_string<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    <span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else if <span class="Delimiter">(</span>is_mu_string<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    <span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else <span class="Delimiter">{</span>
    raise_error &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;first ingredient of 'restore' should be a string, but got &quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>to_string<span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
case RESTORE: <span class="Delimiter">{</span>
  string filename<span class="Delimiter">;</span>
  if <span class="Delimiter">(</span>is_literal_string<span class="Delimiter">(</span>current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    filename = current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>name<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else if <span class="Delimiter">(</span>is_mu_string<span class="Delimiter">(</span>current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    filename = read_mu_string<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">));</span>
  <span class="Delimiter">}</span>
  if <span class="Delimiter">(</span>Current_scenario<span class="Delimiter">)</span> <span class="Delimiter">{</span>
    <span class="Comment">// do nothing in tests</span>
    products<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
    products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>push_back<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  string contents = slurp<span class="Delimiter">(</span><span class="Constant">&quot;lesson/&quot;</span>+filename<span class="Delimiter">);</span>
  products<span class="Delimiter">.</span>resize<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">);</span>
  if <span class="Delimiter">(</span>contents<span class="Delimiter">.</span>empty<span class="Delimiter">())</span>
    products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>push_back<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">);</span>
  else
    products<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>push_back<span class="Delimiter">(</span>new_mu_string<span class="Delimiter">(</span>contents<span class="Delimiter">));</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(code)</span>
string slurp<span class="Delimiter">(</span>const string&amp; filename<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  ostringstream result<span class="Delimiter">;</span>
  ifstream fin<span class="Delimiter">(</span>filename<span class="Delimiter">.</span>c_str<span class="Delimiter">());</span>
  fin<span class="Delimiter">.</span>peek<span class="Delimiter">();</span>
  if <span class="Delimiter">(</span>!fin<span class="Delimiter">)</span> <span class="Identifier">return</span> result<span class="Delimiter">.</span>str<span class="Delimiter">();</span>  <span class="Comment">// don't bother checking errno</span>
  const int N = <span class="Constant">1024</span><span class="Delimiter">;</span>
  char buf[N]<span class="Delimiter">;</span>
  while <span class="Delimiter">(</span>!fin<span class="Delimiter">.</span>eof<span class="Delimiter">())</span> <span class="Delimiter">{</span>
    bzero<span class="Delimiter">(</span>buf<span class="Delimiter">,</span> N<span class="Delimiter">);</span>
    fin<span class="Delimiter">.</span>read<span class="Delimiter">(</span>buf<span class="Delimiter">,</span> N-<span class="Constant">1</span><span class="Delimiter">);</span>  <span class="Comment">// leave at least one null</span>
    result &lt;&lt; buf<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  fin<span class="Delimiter">.</span>close<span class="Delimiter">();</span>
  <span class="Identifier">return</span> result<span class="Delimiter">.</span>str<span class="Delimiter">();</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(before &quot;End Primitive Recipe Declarations&quot;)</span>
SAVE<span class="Delimiter">,</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Numbers&quot;)</span>
put<span class="Delimiter">(</span>Recipe_ordinal<span class="Delimiter">,</span> <span class="Constant">&quot;save&quot;</span><span class="Delimiter">,</span> SAVE<span class="Delimiter">);</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Checks&quot;)</span>
case SAVE: <span class="Delimiter">{</span>
  if <span class="Delimiter">(</span>SIZE<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">)</span> != <span class="Constant">2</span><span class="Delimiter">)</span> <span class="Delimiter">{</span>
    raise_error &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;'save' requires exactly two ingredients, but got &quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>to_string<span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  if <span class="Delimiter">(</span>is_literal_string<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    <span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else if <span class="Delimiter">(</span>is_mu_string<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    <span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else <span class="Delimiter">{</span>
    raise_error &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;first ingredient of 'save' should be a string, but got &quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>to_string<span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  if <span class="Delimiter">(</span>!is_mu_string<span class="Delimiter">(</span>inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    raise_error &lt;&lt; maybe<span class="Delimiter">(</span>get<span class="Delimiter">(</span>Recipe<span class="Delimiter">,</span> r<span class="Delimiter">).</span>name<span class="Delimiter">)</span> &lt;&lt; <span class="Constant">&quot;second ingredient of 'save' should be an address:array:character, but got &quot;</span> &lt;&lt; inst<span class="Delimiter">.</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">).</span>to_string<span class="Delimiter">()</span> &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
    <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>
<span class="Delimiter">:(before &quot;End Primitive Recipe Implementations&quot;)</span>
case SAVE: <span class="Delimiter">{</span>
  if <span class="Delimiter">(</span>Current_scenario<span class="Delimiter">)</span> <span class="Identifier">break</span><span class="Delimiter">;</span>  <span class="Comment">// do nothing in tests</span>
  string filename<span class="Delimiter">;</span>
  if <span class="Delimiter">(</span>is_literal_string<span class="Delimiter">(</span>current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    filename = current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>name<span class="Delimiter">;</span>
  <span class="Delimiter">}</span>
  else if <span class="Delimiter">(</span>is_mu_string<span class="Delimiter">(</span>current_instruction<span class="Delimiter">().</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">)))</span> <span class="Delimiter">{</span>
    filename = read_mu_string<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">));</span>
  <span class="Delimiter">}</span>
  ofstream fout<span class="Delimiter">((</span><span class="Constant">&quot;lesson/&quot;</span>+filename<span class="Delimiter">).</span>c_str<span class="Delimiter">());</span>
  string contents = read_mu_string<span class="Delimiter">(</span>ingredients<span class="Delimiter">.</span>at<span class="Delimiter">(</span><span class="Constant">1</span><span class="Delimiter">).</span>at<span class="Delimiter">(</span><span class="Constant">0</span><span class="Delimiter">));</span>
  fout &lt;&lt; contents<span class="Delimiter">;</span>
  fout<span class="Delimiter">.</span>close<span class="Delimiter">();</span>
  if <span class="Delimiter">(</span>!exists<span class="Delimiter">(</span><span class="Constant">&quot;lesson/.git&quot;</span><span class="Delimiter">))</span> <span class="Identifier">break</span><span class="Delimiter">;</span>
  <span class="Comment">// bug in git: git diff -q messes up --exit-code</span>
  <span class="Comment">// explicitly say '--all' for git 1.9</span>
  int status = system<span class="Delimiter">(</span><span class="Constant">&quot;cd lesson; git add --all .; git diff HEAD --exit-code &gt;/dev/null || git commit -a -m . &gt;/dev/null&quot;</span><span class="Delimiter">);</span>
  if <span class="Delimiter">(</span>status != <span class="Constant">0</span><span class="Delimiter">)</span>
    raise_error &lt;&lt; <span class="Constant">&quot;error in commit: contents &quot;</span> &lt;&lt; contents &lt;&lt; <span class="cSpecial">'\n'</span> &lt;&lt; end<span class="Delimiter">();</span>
  <span class="Identifier">break</span><span class="Delimiter">;</span>
<span class="Delimiter">}</span>

<span class="Delimiter">:(code)</span>
bool exists<span class="Delimiter">(</span>const string&amp; filename<span class="Delimiter">)</span> <span class="Delimiter">{</span>
  struct stat dummy<span class="Delimiter">;</span>
  <span class="Identifier">return</span> <span class="Constant">0</span> == stat<span class="Delimiter">(</span>filename<span class="Delimiter">.</span>c_str<span class="Delimiter">(),</span> &amp;dummy<span class="Delimiter">);</span>
<span class="Delimiter">}</span>
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