Build PDF files using latexmk

docs/guides/feature-flags.rst

@@ -12,6 +12,8 @@ or disable one or more of these featured flags for a particular project.
 Available Flags
 ---------------
 
+``USE_PDF_LATEXMK``: :featureflags:`USE_PDF_LATEXMK`
+
 ``USE_SPHINX_LATEST``: :featureflags:`USE_SPHINX_LATEST`
 
 ``USE_SETUPTOOLS_LATEST``: :featureflags:`USE_SETUPTOOLS_LATEST`

readthedocs/doc_builder/backends/sphinx.py

@@ -6,12 +6,14 @@
 .. _Sphinx: http://www.sphinx-doc.org/
 """
 import codecs
+import itertools
 import logging
 import os
 import shutil
 import sys
 import zipfile
 from glob import glob
+from pathlib import Path
 
 from django.conf import settings
 from django.template import loader as template_loader
@@ -151,6 +153,9 @@ def get_config_params(self):
             'dont_overwrite_sphinx_context': self.project.has_feature(
                 Feature.DONT_OVERWRITE_SPHINX_CONTEXT,
             ),
+            'use_pdf_latexmk': self.project.has_feature(
+                Feature.USE_PDF_LATEXMK,
+            ),
         }
 
         finalize_sphinx_context_data.send(
@@ -395,6 +400,67 @@ def build(self):
             raise BuildEnvironmentError('No TeX files were found')
 
         # Run LaTeX -> PDF conversions
+        if self.project.has_feature(Feature.USE_PDF_LATEXMK):
+            return self._build_latexmk(cwd, latex_cwd)
+
+        return self._build_pdflatex(tex_files, latex_cwd)
+
+    def _build_latexmk(self, cwd, latex_cwd):
+        # These steps are copied from the Makefile generated by Sphinx >= 1.6
+        # https://github.com/sphinx-doc/sphinx/blob/master/sphinx/texinputs/Makefile_t
+        latex_path = Path(latex_cwd)
+        images = []
+        for extension in ('png', 'gif', 'jpg', 'jpeg'):
+            images.extend(latex_path.glob(f'*.{extension}'))
+
+        # FIXME: instead of checking by language here, what we want to check if
+        # ``latex_engine`` is ``platex``
+        pdfs = []
+        if self.project.language == 'ja':
+            # Japanese language is the only one that requires this extra
+            # step. I don't know exactly why but most of the documentation that
+            # I read differentiate this language from the others. I suppose
+            # it's because it mix kanji (Chinese) with its own symbols.
+            pdfs = latex_path.glob('*.pdf')
+
+        for image in itertools.chain(images, pdfs):
+            self.run(
+                'extractbb',
+                image.name,
+                cwd=latex_cwd,
+                record=False,
+            )
+
+        rcfile = 'latexmkrc'
+        if self.project.language == 'ja':
+            rcfile = 'latexmkjarc'
+
+        self.run(
+            'cat',
+            rcfile,
+            cwd=latex_cwd,
+        )
+
+        cmd = self.run(
+            'latexmk',
+            '-r',
+            rcfile,
+
+            # FIXME: check for platex here as well
+            '-pdfdvi' if self.project.language == 'ja' else '-pdf',
+
+            '-dvi-',
+            '-ps-',
+            f'-jobname={self.project.slug}',
+            warn_only=True,
+            cwd=latex_cwd,
+        )
+
+        self.pdf_file_name = f'{self.project.slug}.pdf'
+
+        return cmd.successful
+
+    def _build_pdflatex(self, tex_files, latex_cwd):
         pdflatex_cmds = [
             ['pdflatex', '-interaction=nonstopmode', tex_file]
             for tex_file in tex_files

readthedocs/doc_builder/templates/doc_builder/conf.py.tmpl

@@ -140,3 +140,38 @@ if 'extensions' in globals():
     extensions.insert(0, "readthedocs_ext.readthedocs")
 else:
     extensions = ["readthedocs_ext.readthedocs"]
+
+{% if use_pdf_latexmk %}
+project_language = '{{ project.language }}'
+
+# User's Sphinx configurations
+language_user = globals().get('language', None)
+latex_engine_user = globals().get('latex_engine', None)
+latex_elements_user = globals().get('latex_elements', None)
+
+chinese = any([
+    language_user in ('zh_CN', 'zh_TW'),
+    project_language in ('zh_CN', 'zh_TW'),
+])
+
+japanase = any([
+    language_user == 'ja',
+    project_language == 'ja',
+])
+
+if chinese:
+    latex_engine = latex_engine_user or 'xelatex'
+
+    # Remove this once xindy gets installed in Docker image and XINDYOPS
+    # env variable is supported
+    # https://github.com/rtfd/readthedocs-docker-images/pull/98
+    latex_use_xindy = False
+
+    latex_elements_rtd = {
+        'preamble': '\\usepackage[UTF8]{ctex}\n',
+    }
+    latex_elements = latex_elements_user or latex_elements_rtd
+elif japanase:
+    latex_engine = latex_engine_user or 'platex'
+    latex_use_xindy = False
+{% endif %}

readthedocs/projects/models.py

@@ -1314,10 +1314,12 @@ def add_features(sender, **kwargs):
     DONT_SHALLOW_CLONE = 'dont_shallow_clone'
     USE_TESTING_BUILD_IMAGE = 'use_testing_build_image'
     SHARE_SPHINX_DOCTREE = 'share_sphinx_doctree'
+    USE_PDF_LATEXMK = 'use_pdf_latexmk'
 
     FEATURES = (
         (USE_SPHINX_LATEST, _('Use latest version of Sphinx')),
         (USE_SETUPTOOLS_LATEST, _('Use latest version of setuptools')),
+        (USE_PDF_LATEXMK, _('Use latexmk to build the PDF')),
         (ALLOW_DEPRECATED_WEBHOOKS, _('Allow deprecated webhook views')),
         (PIP_ALWAYS_UPGRADE, _('Always run pip install --upgrade')),
         (SKIP_SUBMODULES, _('Skip git submodule checkout')),