Rewrite default template to handle nested ifs, != and env vars in if

test/test_unit_template_default.py

@@ -1,4 +1,5 @@
 """Unit tests: template_default"""
+
 import os
 
 FILE_MODE = 0o754
@@ -12,6 +13,7 @@
 LOCAL_USER = "default_Test+@-!^User"
 LOCAL_DISTRO = "default_Test+@-!^Distro"
 LOCAL_DISTRO_FAMILY = "default_Test+@-!^Family"
+ENV_VAR = "default_Test+@-!^Env"
 TEMPLATE = f"""
 start of template
 default class         = >{{{{yadm.class}}}}<
@@ -30,6 +32,9 @@
 {{% if yadm.class == "wrongclass1" %}}
 wrong class 1
 {{% endif %}}
+{{% if yadm.class != "wronglcass" %}}
+Included section from !=
+{{%     endif\t\t  %}}
 {{% if yadm.class == "{LOCAL_CLASS}" %}}
 Included section for class = {{{{yadm.class}}}} ({{{{yadm.class}}}} repeated)
 Multiple lines
@@ -97,6 +102,13 @@
 {{% if yadm.distro_family == "wrongfamily2" %}}
 wrong family 2
 {{% endif %}}
+{{% if env.VAR == "{ENV_VAR}" %}}
+Included section for env.VAR = {{{{env.VAR}}}} ({{{{env.VAR}}}} again)
+{{% endif %}}
+{{% if env.VAR == "wrongenvvar" %}}
+wrong env.VAR
+{{% endif %}}
+yadm.no_such_var="{{{{ yadm.no_such_var }}}}" and env.NO_SUCH_VAR="{{{{ env.NO_SUCH_VAR }}}}"
 end of template
 """
 EXPECTED = f"""
@@ -111,6 +123,7 @@
 classes = >{LOCAL_CLASS2}
 {LOCAL_CLASS}<
 Included section from else
+Included section from !=
 Included section for class = {LOCAL_CLASS} ({LOCAL_CLASS} repeated)
 Multiple lines
 Included section for second class
@@ -121,6 +134,8 @@
 Included section for distro = {LOCAL_DISTRO} ({LOCAL_DISTRO} again)
 Included section for distro_family = \
 {LOCAL_DISTRO_FAMILY} ({LOCAL_DISTRO_FAMILY} again)
+Included section for env.VAR = {ENV_VAR} ({ENV_VAR} again)
+yadm.no_such_var="" and env.NO_SUCH_VAR=""
 end of template
 """
 
@@ -138,7 +153,7 @@
 An empty file removes the line above
 {%include basic%}
 {% include "./variables.{{ yadm.os }}"  %}
-{% include dir/nested %}
+  {% include dir/nested %}
 Include basic again:
 {% include basic %}
 """
@@ -154,6 +169,42 @@
 basic
 """
 
+TEMPLATE_NESTED_IFS = """\
+{% if yadm.user == "me" %}
+    print1
+  {% if yadm.user == "me" %}
+    print2
+  {% else %}
+    no print1
+  {% endif %}
+{% else %}
+  {% if yadm.user == "me" %}
+    no print2
+  {% else %}
+    no print3
+  {% endif %}
+{% endif %}
+{% if yadm.user != "me" %}
+    no print4
+  {% if yadm.user == "me" %}
+    no print5
+  {% else %}
+    no print6
+  {% endif %}
+{% else %}
+  {% if yadm.user == "me" %}
+    print3
+  {% else %}
+    no print7
+  {% endif %}
+{% endif %}
+"""
+EXPECTED_NESTED_IFS = """\
+    print1
+    print2
+    print3
+"""
+
 
 def test_template_default(runner, yadm, tmpdir):
     """Test template_default"""
@@ -182,7 +233,7 @@ def test_template_default(runner, yadm, tmpdir):
         local_distro_family="{LOCAL_DISTRO_FAMILY}"
         template_default "{input_file}" "{output_file}"
     """
-    run = runner(command=["bash"], inp=script)
+    run = runner(command=["bash"], inp=script, env={"VAR": ENV_VAR})
     assert run.success
     assert run.err == ""
     assert output_file.read() == EXPECTED
@@ -243,12 +294,30 @@ def test_include(runner, yadm, tmpdir):
     assert os.stat(output_file).st_mode == os.stat(input_file).st_mode
 
 
+def test_nested_ifs(runner, yadm, tmpdir):
+    """Test nested if statements"""
+
+    input_file = tmpdir.join("input")
+    input_file.write(TEMPLATE_NESTED_IFS, ensure=True)
+    output_file = tmpdir.join("output")
+
+    script = f"""
+        YADM_TEST=1 source {yadm}
+        set_awk
+        local_user="me"
+        template_default "{input_file}" "{output_file}"
+    """
+    run = runner(command=["bash"], inp=script)
+    assert run.success
+    assert run.err == ""
+    assert output_file.read() == EXPECTED_NESTED_IFS
+
+
 def test_env(runner, yadm, tmpdir):
     """Test env"""
 
     input_file = tmpdir.join("input")
     input_file.write("{{env.PWD}}", ensure=True)
-    input_file.chmod(FILE_MODE)
     output_file = tmpdir.join("output")
 
     script = f"""

yadm

@@ -368,87 +368,110 @@ function template_default() {
   # the explicit "space + tab" character class used below is used because not
   # all versions of awk seem to support the POSIX character classes [[:blank:]]
   read -r -d '' awk_pgm << "EOF"
-# built-in default template processor
 BEGIN {
-  blank              = "[ 	]"
-  c["class"]         = class
-  c["classes"]       = classes
-  c["arch"]          = arch
-  c["os"]            = os
-  c["hostname"]      = host
-  c["user"]          = user
-  c["distro"]        = distro
-  c["distro_family"] = distro_family
-  c["source"]        = source
-  ifs                = "^{%" blank "*if"
-  els                = "^{%" blank "*else" blank "*%}$"
-  end                = "^{%" blank "*endif" blank "*%}$"
-  skp                = "^{%" blank "*(if|else|endif)"
-  vld                = conditions()
-  inc_start          = "^{%" blank "*include" blank "+\"?"
-  inc_end            = "\"?" blank "*%}$"
-  inc                = inc_start ".+" inc_end
-  prt                = 1
-  err                = 0
-}
-END { exit err }
-{ replace_vars() } # variable replacements
-$0 ~ vld, $0 ~ end {
-  if ($0 ~ vld || $0 ~ end) prt=1;
-  if ($0 ~ els) prt=0;
-  if ($0 ~ skp) next;
-}
-($0 ~ ifs && $0 !~ vld), $0 ~ end {
-  if ($0 ~ ifs && $0 !~ vld) prt=0;
-  if ($0 ~ els || $0 ~ end) prt=1;
-  if ($0 ~ skp) next;
-}
-{ if (!prt) next }
-$0 ~ inc {
-  file = $0
-  sub(inc_start, "", file)
-  sub(inc_end, "", file)
-  sub(/^[^\/].*$/, source_dir "/&", file)
-
-  while ((res = getline <file) > 0) {
-    replace_vars()
-    print
-  }
-  if (res < 0) {
-    printf "%s:%d: error: could not read '%s'\n", FILENAME, NR, file | "cat 1>&2"
-    err = 1
-  }
-  close(file)
-  next
-}
-{ print }
-function replace_vars() {
-  for (label in c) {
-    gsub(("{{" blank "*yadm\\." label blank "*}}"), c[label])
+  yadm["class"] = class
+  yadm["classes"] = classes
+  yadm["arch"] = arch
+  yadm["os"] = os
+  yadm["hostname"] = host
+  yadm["user"] = user
+  yadm["distro"] = distro
+  yadm["distro_family"] = distro_family
+  yadm["source"] = source
+
+  VARIABLE = "(env|yadm)\\.[a-zA-Z0-9_]+"
+
+  current = 0
+  filename[current] = ARGV[1]
+  line[current] = 0
+
+  level = 0
+  skip[level] = 0
+
+  for (; current >= 0; --current) {
+    while ((res = getline <filename[current]) > 0) {
+      ++line[current]
+      if ($0 ~ "^[ \t]*\\{%[ \t]*if[ \t]+" VARIABLE "[ \t]*[!=]=[ \t]*\".*\"[ \t]*%\\}$") {
+        if (skip[level]) { skip[++level] = 1; continue }
+
+        match($0, VARIABLE)
+        lhs = substr($0, RSTART, RLENGTH)
+        match($0, /[!=]=/)
+        op = substr($0, RSTART, RLENGTH)
+        match($0, /".*"/)
+        rhs = replace_vars(substr($0, RSTART + 1, RLENGTH - 2))
+
+        if (lhs == "yadm.class") {
+          lhs = "not" rhs
+          split(classes, cls_array, "\n")
+          for (idx in cls_array) {
+            if (rhs == cls_array[idx]) { lhs = rhs; break }
+          }
+        }
+        else {
+          lhs = replace_vars("{{" lhs "}}")
+        }
+
+        if (op == "==") { skip[++level] = lhs != rhs }
+        else { skip[++level] = lhs == rhs }
+      }
+      else if (/^[ \t]*\{%[ \t]*else[ \t]*%\}$/) {
+        if (level == 0 || skip[level] < 0) { error("else without matching if") }
+        skip[level] = skip[level] ? skip[level - 1] : -1
+      }
+      else if (/^[ \t]*\{%[ \t]*endif[ \t]*%\}$/) {
+        if (--level < 0) { error("endif without matching if") }
+      }
+      else if (!skip[level]) {
+        $0 = replace_vars($0)
+        if (match($0, /^[ \t]*\{%[ \t]*include[ \t]+("[^"]+"|[^"]+)[ \t]*%\}$/)) {
+          include = $0
+          sub(/^[ \t]*\{%[ \t]*include[ \t]+"?/, "", include)
+          sub(/"?[ \t]*%\}$/, "", include)
+          if (index(include, "/") != 1) {
+            include = source_dir "/" include
+          }
+          filename[++current] = include
+          line[current] = 0
+        }
+        else { print }
+      }
+    }
+    if (res >= 0) { close(filename[current]) }
+    else if (current == 0) { error("could not read input file") }
+    else { --current; error("could not read include file '" filename[current + 1] "'") }
   }
-  for (label in ENVIRON) {
-    gsub(("{{" blank "*env\\." label blank "*}}"), ENVIRON[label])
+  if (level > 0) {
+    current = 0
+    error("unterminated if")
   }
+  exit 0
 }
-function condition_helper(label, value) {
-  gsub(/[\\.^$(){}\[\]|*+?]/, "\\\\&", value)
-  return sprintf("yadm\\.%s" blank "*==" blank "*\"%s\"", label, value)
+function error(text) {
+  printf "%s:%d: error: %s\n",
+    filename[current], line[current], text > "/dev/stderr"
+  exit 1
 }
-function conditions() {
-  pattern = ifs blank "+("
-  for (label in c) {
-    if (label != "class") {
-      value = c[label]
-      pattern = sprintf("%s%s|", pattern, condition_helper(label, value));
+function replace_vars(input) {
+  output = ""
+  while (match(input, "\\{\\{[ \t]*" VARIABLE "[ \t]*\\}\\}")) {
+    if (RSTART > 1) {
+      output = output substr(input, 0, RSTART - 1)
+    }
+    data = substr(input, RSTART + 2, RLENGTH - 4)
+    input = substr(input, RSTART + RLENGTH)
+
+    gsub(/[ \t]+/, "", data)
+    split(data, fields, /\./)
+
+    if (fields[1] == "env") {
+      output = output ENVIRON[fields[2]]
+    }
+    else {
+      output = output yadm[fields[2]]
     }
   }
-  split(classes, cls_array, "\n")
-  for (idx in cls_array) {
-    value = cls_array[idx]
-    pattern = sprintf("%s%s|", pattern, condition_helper("class", value));
-  }
-  sub(/\|$/, ")" blank "*%}$", pattern)
-  return pattern
+  return output input
 }
 EOF