Extract import-file remapping logic out of CompilerStack into ImportRemapper.

libsolidity/interface/CompilerStack.cpp

@@ -24,6 +24,7 @@
 
 
 #include <libsolidity/interface/CompilerStack.h>
+#include <libsolidity/interface/ImportRemapper.h>
 
 #include <libsolidity/analysis/ControlFlowAnalyzer.h>
 #include <libsolidity/analysis/ControlFlowGraph.h>
@@ -196,33 +197,13 @@ void CompilerStack::findAndReportCyclicContractDependencies()
 	}
 }
 
-std::optional<CompilerStack::Remapping> CompilerStack::parseRemapping(string const& _remapping)
-{
-	auto eq = find(_remapping.begin(), _remapping.end(), '=');
-	if (eq == _remapping.end())
-		return {};
-
-	auto colon = find(_remapping.begin(), eq, ':');
-
-	Remapping r;
-
-	r.context = colon == eq ? string() : string(_remapping.begin(), colon);
-	r.prefix = colon == eq ? string(_remapping.begin(), eq) : string(colon + 1, eq);
-	r.target = string(eq + 1, _remapping.end());
-
-	if (r.prefix.empty())
-		return {};
-
-	return r;
-}
-
-void CompilerStack::setRemappings(vector<Remapping> const& _remappings)
+void CompilerStack::setRemappings(vector<ImportRemapper::Remapping> _remappings)
 {
 	if (m_stackState >= ParsedAndImported)
 		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_comment("Must set remappings before parsing."));
 	for (auto const& remapping: _remappings)
 		solAssert(!remapping.prefix.empty(), "");
-	m_remappings = _remappings;
+	m_importRemapper.setRemappings(move(_remappings));
 }
 
 void CompilerStack::setViaIR(bool _viaIR)
@@ -312,7 +293,7 @@ void CompilerStack::reset(bool _keepSettings)
 	m_unhandledSMTLib2Queries.clear();
 	if (!_keepSettings)
 	{
-		m_remappings.clear();
+		m_importRemapper.clear();
 		m_libraries.clear();
 		m_viaIR = false;
 		m_evmVersion = langutil::EVMVersion();
@@ -1170,43 +1151,7 @@ StringMap CompilerStack::loadMissingSources(SourceUnit const& _ast, std::string
 string CompilerStack::applyRemapping(string const& _path, string const& _context)
 {
 	solAssert(m_stackState < ParsedAndImported, "");
-	// Try to find the longest prefix match in all remappings that are active in the current context.
-	auto isPrefixOf = [](string const& _a, string const& _b)
-	{
-		if (_a.length() > _b.length())
-			return false;
-		return std::equal(_a.begin(), _a.end(), _b.begin());
-	};
-
-	size_t longestPrefix = 0;
-	size_t longestContext = 0;
-	string bestMatchTarget;
-
-	for (auto const& redir: m_remappings)
-	{
-		string context = util::sanitizePath(redir.context);
-		string prefix = util::sanitizePath(redir.prefix);
-
-		// Skip if current context is closer
-		if (context.length() < longestContext)
-			continue;
-		// Skip if redir.context is not a prefix of _context
-		if (!isPrefixOf(context, _context))
-			continue;
-		// Skip if we already have a closer prefix match.
-		if (prefix.length() < longestPrefix && context.length() == longestContext)
-			continue;
-		// Skip if the prefix does not match.
-		if (!isPrefixOf(prefix, _path))
-			continue;
-
-		longestContext = context.length();
-		longestPrefix = prefix.length();
-		bestMatchTarget = util::sanitizePath(redir.target);
-	}
-	string path = bestMatchTarget;
-	path.append(_path.begin() + static_cast<string::difference_type>(longestPrefix), _path.end());
-	return path;
+	return m_importRemapper.apply(_path, _context);
 }
 
 void CompilerStack::resolveImports()
@@ -1584,7 +1529,7 @@ string CompilerStack::createMetadata(Contract const& _contract) const
 
 	meta["settings"]["remappings"] = Json::arrayValue;
 	set<string> remappings;
-	for (auto const& r: m_remappings)
+	for (auto const& r: m_importRemapper.remappings())
 		remappings.insert(r.context + ":" + r.prefix + "=" + r.target);
 	for (auto const& r: remappings)
 		meta["settings"]["remappings"].append(r);

libsolidity/interface/CompilerStack.h

@@ -26,6 +26,7 @@
 
 #include <libsolidity/analysis/FunctionCallGraph.h>
 #include <libsolidity/interface/ReadFile.h>
+#include <libsolidity/interface/ImportRemapper.h>
 #include <libsolidity/interface/OptimiserSettings.h>
 #include <libsolidity/interface/Version.h>
 #include <libsolidity/interface/DebugSettings.h>
@@ -111,13 +112,6 @@ public:
 		None
 	};
 
-	struct Remapping
-	{
-		std::string context;
-		std::string prefix;
-		std::string target;
-	};
-
 	/// Creates a new compiler stack.
 	/// @param _readFile callback used to read files for import statements. Must return
 	/// and must not emit exceptions.
@@ -139,12 +133,9 @@ public:
 	/// all settings are reset as well.
 	void reset(bool _keepSettings = false);
 
-	// Parses a remapping of the format "context:prefix=target".
-	static std::optional<Remapping> parseRemapping(std::string const& _remapping);
-
 	/// Sets path remappings.
 	/// Must be set before parsing.
-	void setRemappings(std::vector<Remapping> const& _remappings);
+	void setRemappings(std::vector<ImportRemapper::Remapping> _remappings);
 
 	/// Sets library addresses. Addresses are cleared iff @a _libraries is missing.
 	/// Must be set before parsing.
@@ -487,9 +478,7 @@ private:
 	bool m_generateIR = false;
 	bool m_generateEwasm = false;
 	std::map<std::string, util::h160> m_libraries;
-	/// list of path prefix remappings, e.g. mylibrary: github.com/ethereum = /usr/local/ethereum
-	/// "context:prefix=target"
-	std::vector<Remapping> m_remappings;
+	ImportRemapper m_importRemapper;
 	std::map<std::string const, Source> m_sources;
 	// if imported, store AST-JSONS for each filename
 	std::map<std::string, Json::Value> m_sourceJsons;

libsolidity/interface/ImportRemapper.cpp

@@ -0,0 +1,100 @@
+/*
+	This file is part of solidity.
+
+	solidity 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, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+#include <libsolidity/interface/ImportRemapper.h>
+#include <libsolutil/CommonIO.h>
+#include <liblangutil/Exceptions.h>
+
+using std::equal;
+using std::move;
+using std::optional;
+using std::string;
+using std::string;
+using std::vector;
+
+namespace solidity::frontend
+{
+
+void ImportRemapper::setRemappings(vector<Remapping> _remappings)
+{
+	for (auto const& remapping: _remappings)
+		solAssert(!remapping.prefix.empty(), "");
+	m_remappings = move(_remappings);
+}
+
+SourceUnitName ImportRemapper::apply(ImportPath const& _path, string const& _context) const
+{
+	// Try to find the longest prefix match in all remappings that are active in the current context.
+	auto isPrefixOf = [](string const& _a, string const& _b)
+	{
+		if (_a.length() > _b.length())
+			return false;
+		return equal(_a.begin(), _a.end(), _b.begin());
+	};
+
+	size_t longestPrefix = 0;
+	size_t longestContext = 0;
+	string bestMatchTarget;
+
+	for (auto const& redir: m_remappings)
+	{
+		string context = util::sanitizePath(redir.context);
+		string prefix = util::sanitizePath(redir.prefix);
+
+		// Skip if current context is closer
+		if (context.length() < longestContext)
+			continue;
+		// Skip if redir.context is not a prefix of _context
+		if (!isPrefixOf(context, _context))
+			continue;
+		// Skip if we already have a closer prefix match.
+		if (prefix.length() < longestPrefix && context.length() == longestContext)
+			continue;
+		// Skip if the prefix does not match.
+		if (!isPrefixOf(prefix, _path))
+			continue;
+
+		longestContext = context.length();
+		longestPrefix = prefix.length();
+		bestMatchTarget = util::sanitizePath(redir.target);
+	}
+	string path = bestMatchTarget;
+	path.append(_path.begin() + static_cast<string::difference_type>(longestPrefix), _path.end());
+	return path;
+}
+
+optional<ImportRemapper::Remapping> ImportRemapper::parseRemapping(string const& _remapping)
+{
+	auto eq = find(_remapping.begin(), _remapping.end(), '=');
+	if (eq == _remapping.end())
+		return {};
+
+	auto colon = find(_remapping.begin(), eq, ':');
+
+	Remapping r;
+
+	r.context = colon == eq ? string() : string(_remapping.begin(), colon);
+	r.prefix = colon == eq ? string(_remapping.begin(), eq) : string(colon + 1, eq);
+	r.target = string(eq + 1, _remapping.end());
+
+	if (r.prefix.empty())
+		return {};
+
+	return r;
+}
+
+}

libsolidity/interface/ImportRemapper.h

@@ -0,0 +1,59 @@
+/*
+	This file is part of solidity.
+
+	solidity 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, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+namespace solidity::frontend
+{
+
+// Some helper typedefs to make reading the signatures more self explaining.
+using SourceUnitName = std::string;
+using SourceCode = std::string;
+using ImportPath = std::string;
+
+/// The ImportRemapper is being used on imported file paths for being remapped to source unit IDs before being loaded.
+class ImportRemapper
+{
+public:
+	struct Remapping
+	{
+		std::string context;
+		std::string prefix;
+		std::string target;
+	};
+
+	void clear() { m_remappings.clear(); }
+
+	void setRemappings(std::vector<Remapping> _remappings);
+	std::vector<Remapping> const& remappings() const noexcept { return m_remappings; }
+
+	SourceUnitName apply(ImportPath const& _path, std::string const& _context) const;
+
+	// Parses a remapping of the format "context:prefix=target".
+	static std::optional<Remapping> parseRemapping(std::string const& _remapping);
+
+private:
+	/// list of path prefix remappings, e.g. mylibrary: github.com/ethereum = /usr/local/ethereum
+	/// "context:prefix=target"
+	std::vector<Remapping> m_remappings = {};
+};
+
+}

libsolidity/interface/StandardCompiler.cpp

@@ -22,6 +22,7 @@
  */
 
 #include <libsolidity/interface/StandardCompiler.h>
+#include <libsolidity/interface/ImportRemapper.h>
 
 #include <libsolidity/ast/ASTJsonConverter.h>
 #include <libyul/AssemblyStack.h>
@@ -810,7 +811,7 @@ std::variant<StandardCompiler::InputsAndSettings, Json::Value> StandardCompiler:
 	{
 		if (!remapping.isString())
 			return formatFatalError("JSONError", "\"settings.remappings\" must be an array of strings");
-		if (auto r = CompilerStack::parseRemapping(remapping.asString()))
+		if (auto r = ImportRemapper::parseRemapping(remapping.asString()))
 			ret.remappings.emplace_back(std::move(*r));
 		else
 			return formatFatalError("JSONError", "Invalid remapping: \"" + remapping.asString() + "\"");
@@ -941,7 +942,7 @@ Json::Value StandardCompiler::compileSolidity(StandardCompiler::InputsAndSetting
 	compilerStack.setViaIR(_inputsAndSettings.viaIR);
 	compilerStack.setEVMVersion(_inputsAndSettings.evmVersion);
 	compilerStack.setParserErrorRecovery(_inputsAndSettings.parserErrorRecovery);
-	compilerStack.setRemappings(_inputsAndSettings.remappings);
+	compilerStack.setRemappings(move(_inputsAndSettings.remappings));
 	compilerStack.setOptimiserSettings(std::move(_inputsAndSettings.optimiserSettings));
 	compilerStack.setRevertStringBehaviour(_inputsAndSettings.revertStrings);
 	compilerStack.setLibraries(_inputsAndSettings.libraries);

libsolidity/interface/StandardCompiler.h

@@ -64,7 +64,7 @@ private:
 		std::map<std::string, std::string> sources;
 		std::map<util::h256, std::string> smtLib2Responses;
 		langutil::EVMVersion evmVersion;
-		std::vector<CompilerStack::Remapping> remappings;
+		std::vector<ImportRemapper::Remapping> remappings;
 		RevertStrings revertStrings = RevertStrings::Default;
 		OptimiserSettings optimiserSettings = OptimiserSettings::minimal();
 		std::map<std::string, util::h160> libraries;